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Decentralised Composting for Cities of Low- and Middle- Income Countries -- A Users’ Manual

Authors:
Decentralised Composting for
Cities of Low- and Middle-
Income Countries
A Users’ Manual
Waste Concern
Iftekhar Enayetullah
A. H. Md. Maqsood Sinha
1
Eawag / Sandec
Silke Rothenberger
Christian Zurbrügg
Publisher: Waste Concern, House - 21 (Side B), Road - 7, Block - G,
Banani Model Town, Dhaka-1213, Bangladesh; and
Eawag, P.O. Box 611, 8600 Duebendorf, Switzerland
Copyright: 2006 - Published texts and figures may be reproduced
freely for non-commercial purposes only (except when reproduction
or translation rights are explicitly reserved), provided that mentions
is made of the authors and this publication.
Circulation: 1000 copies (to be ordered from www.sandec.ch or
www.wasteconcern.org)
ISBN 978-3-906484-36-5
2
Foreword
This book is about converting organic waste into resource - a partnership - based and decentralised approach to waste
composting. It is based on actual ground level experience of Waste Concern-our partner organisation in implementing several
decentralised composting projects in Dhaka as well as replication in Bangladesh and other Asian cities.
Solid waste management has become a major environmental problem for the fast growing towns and cities of low and middle-
income countries. Most urban local bodies in the developing countries are cash-strapped and unable to provide satisfactory
waste management services. In most cities not even 50 percent of the generated waste is collected. The present solid waste
management system in developing countries is based on the "end of the pipe" solution, i.e., collection -transportation-crude
dumping of waste with limited recycling of inorganic waste, mainly by the informal sector.
The physical composition of solid waste of the developing countries consists mostly of organic matter, which is biodegradable.
When organic waste remains uncollected in the streets, drains or when disposed in open crude dump sites, it poses three
major environmental problems: firstly, ground and surface water pollution through leachates; secondly, spread of disease
vectors from open and uncovered waste dumped in crude dump sites; and thirdly, emission of methane which is a major green
house gas due to anaerobic condition in the dump sites.
In order to avoid the solid waste - triggered environmental hazards, use of compost needs to be promoted. One of the
sustainable approaches is to look at waste as a resource, not as a problem. This manual demonstrates that it is possible to
turn waste into jobs and opportunity for the poor, and improve food security.
This manual provides step-by-step guidelines on how to initiate a decentralised composting project in a developing country.
It is our hope that this resource book on composting and solid waste management will prove to be indispensable to
communities and practitioners alike, especially for the urban local bodies, private sector and NGOs.
Larry Maramis
Deputy Resident Representative
United Nations Development Programme (UNDP), Bangladesh
3
Foreword
Urban solid waste management is considered to be one of the most immediate and serious environmental problems
confronting urban governments in developing countries. The severity of this challenge will increase in the future given the
trends of rapid urbanisation and growth in urban population.
Inadequate collection and disposal of waste poses a serious health risk to the population and is an obvious cause of
environmental degradation in most cities of the developing world. With growing public pressure and environmental legislation,
the waste experts are being called upon to develop more sustainable methods of dealing with municipal waste. One step in
improving the current solid waste situation is enhancing resource recovering activities. Recycling inorganic materials from
municipal solid waste is often well developed by the activities of the informal sector. Reuse of organic waste material however,
often contributing to more than 50% of the total waste amount, is still fairly limited but has interesting recovery potential.
Coupled with approaches to reduce reliance on landfill as a disposal route, biological treatment is increasingly becoming
adopted as a standard requirement for the vast majority of biodegradable wastes. This book deals with such urban organic
municipal wastes from households, commercial activities, institutions, as well as gardens and parks. It describes approaches
and methods of composting on neighbourhood level in small -and middle- scale plants. It considers issues of primary waste
collection, composting methods, management systems, occupational health, product quality, marketing and end - user
demands.
The existing physical plan and socio -economical situation of many cities in low -and middle -income countries strongly favours
the implementation of decentralised composting systems.
Decentralised composting systems are less technology dependent. Low cost, locally available materials and simple
technology can be used.
In contrast to decentralised composting systems, centralized options require technical machinery of high capital cost as
well as high maintenance costs and a high degree of specialized skills is also required, and so they are prone to a higher
risk of failure.
Decentralised options are labour-intensive, generate employment and- given the low labour costs - are more cost-effective.
Such options enhance income and job opportunity for the poor, socially deprived, informal workers and small entrepreneurs
and provide ideal opportunities for public- private partnerships.
Decentralised options are well suited for the waste stream, climate, and social and economic conditions of low - and
middle-income countries.
Decentralised waste management enhances and improves environmental awareness of the beneficiaries. Source-
segregation by the residents reduces the volume of solid waste earmarked for disposal effectively and increases the value
of recyclables.
Decentralised systems reduce the cost incurred for the collection, transportation and disposal of waste by the municipal
authority.
This manual serves to create and contribute towards an enabling environment in order to promote, replicate and strengthen
decentralised composting worldwide.
François Muenger
Senior Water and Sanitation Advisor
Swiss Agency for Development and Cooperation (SDC)
4
Table of Contents
Introduction 7
Launching a Collection and Composting Scheme 9
Activity 1 Determine the opportunities and threats for your composting project 9
Task 1 Identifying Stakeholder Interests 13
Activity 1 Identify project stakeholders 13
Activity 2 Identify environmental legislation and land use regulations 14
Activity 3 Identify potential marketing options 15
Task 2 Assessing Target Community Interests and Land Availability 19
Activity 1 Organise a community meeting 19
Activity 2 Conduct a structured survey using a questionnaire 20
Activity 3 Assess land availability and visit proposed sites 21
Task 3 Data Collection 25
Activity 1 Determine the solid waste generation 25
Activity 2 Analyse the solid waste composition 26
Activity 3 Assess topography and road conditions 27
Task 4 Preparing a Business Plan and Financial Projections 31
Activity 1 Develop an appropriate management model 31
Activity 2 Determine the viability of the project: Benefit - Cost Analysis 34
Activity 3 Develop the contract for involved partners 38
Task 5 Development and Design of Collection System 41
Activity 1 Select the most appropriate vehicles 41
Activity 2 Select the appropriate waste collection system 43
Activity 3 Calculate the number of vehicles required 44
Activity 4 Community participation and mobilisation for waste collection 44
Activity 5 Organise and introduce fee collection 45
Activity 6 Try to promote source segregation 45
Task 6 Design and Construction of Composting Facility 49
Activity 1 Plan and decide on the composting plant layout 49
Activity 2 Plan the required key features 50
Activity 3 Plan staffing requirements 54
Activity 4 Plan additional equipment and expendables 54
Task 7 Operating and Maintaining a Composting Facility 57
Activity 1 Operation and monitoring 57
Activity 2 Trouble shooting 66
Activity 3 Control the quality of compost 67
Task 8 Marketing of Compost 71
Activity 1 Assess potential customers and competitors 71
Activity 2 Develop a marketing strategy 71
Activity 3 Define your product 73
Activity 4 Create a market map 75
5
Annex
Annex 1 Overview - Timetable for Planning and Implementation 81
Annex 2 Basics of Statistical Analysis for Community Surveys 82
Annex 3 Questionnaire for Community Surveys 83
Annex 4 Layouts of Two Composting Plants 85
4A: Windrow-composting system, layout plan 85
4B: a) Box-composting system, layout plan 86
4B: b) Box-composting system, cross section view 87
4C: Details of box composting system 88
Annex 5 Template for Both a Memorandum of Understanding (MoU) and a Final Contract
Between the Involved Parties 90
Annex 6 Analysis of Waste Generation and Physical Composition as Conducted by
Waste Concern in Bangladesh 93
Annex 7 The Science of Composting 98
Annex 8 Compost Quality Standards 100
Annex 9 Templates for Compost Monitoring 101
Template 1 Monitoring Table for Single Windrow 101
Template 2 Temperature Monitoring Table for Several Windrow (in ºC) 102
Template 3 Temperature Graph for Composting 103
Template 4 Final Quality Control Sheet for Compost 104
Annex 10 Preliminary Compost Application Guide 105
Annex 11 Definitions and Glossary 106
Annex 12 Authors and Reviewers 108
6
Solid waste generation and management is an issue of
increasing concern in many developing countries, as it is
one of the most immediate and serious environmental
problems confronting local governments. Waste, if just
dumped on a landfill site, is a misplaced resource causing
further environmental problems. Integrated waste
management focuses on recycling and reuse of different
waste types: biodegradable waste composting is but one
option. However, experience has shown that many
composing schemes have failed in the past on account of
inappropriate technologies, lack of markets for the product
and weak business models. In Europe legislation has
already proceeded as far as to restrict biodegradable waste
disposal to landfill sites. These landfill directives compel
actions towards an integrated organic waste management,
in which composting and biogas production from organic
waste play an important role. Upcoming environmental
legislation in developing countries also allow the
development of clear organisational structures, formation of
verified partnerships and application of business models
which are favourable to composting schemes.
This handbook
provides assistance in setting up decentralised
composting schemes to mitigate the problem of
municipal organic solid waste management in cities of
developing countries,
is mainly concerned with systems suited to
neighbourhoods - primary waste collection systems
and composting plants with capacities up to five tons
per day,
provides insights into the prevailing challenges of
decentralised composting schemes, and recommends
measures to avoid such problems through improved
strategic planning, organisational, institutional, and
operational procedures.
This document benefits largely from the experience of Waste
Concern, a research-based NGO in Dhaka, Bangladesh.
Experience, which is derived from nine years of operation of
a community-based pilot composting plant in Dhaka, as well
as the initiation and support of 38 replications in 18 towns in
Bangladesh by February 2005. Waste Concern’s experience
reveals that community-based composting plants can be
financially viable and sustainable provided that:
a) legal and institutional conditions for establishing such
schemes are considered,
b) suitable financial and management models are taken
into account, and
c) appropriate technologies are applied and a sound
operation ensured.
Sandec (Water and Sanitation in Developing Countries), a
department of the Swiss Federal Institute of Aquatic
Science and Technology (Eawag), complemented the
experience of Waste Concern with more general research
findings and specific data from other composting schemes
of similar scale and nature in India, Indonesia, Sri Lanka,
Vietnam, Burkina Faso, and Chile. Detailed information
regarding specific cases is given in text boxes, and
reference is made to further case study documents for each
chapter.
This document attempts to synthesise the experience
worldwide, and to provide guidance on key aspects the
authors consider to be “generally valid”. Mention should be
made that this handbook is not a recipe to be followed
blindly. Case-specific, local aspects, such as political and
social systems, geography and climate, etc., should always
be integrated in project planning. For a specific local city or
country context, certain aspects and issues may obviously
be more or less relevant, however, the needs have to be
systematically analysed for each individual project – a fact
that this handbook cannot take into account.
Expected users of this handbook
This manual has been prepared for use by local non-
governmental and community-based organisations (e.g.
resident initiatives) and relevant persons in urban local
governments. Private organisations or entrepreneurs
interested in organic waste recycling may also benefit from
this book. It may also help development agencies and other
government sectors in planning waste management and
composting programmes. It can be used as a basic source
of information when negotiating with municipal authorities or
advocating improved organic waste management strategies
or policies.
7
Introduction
All human actions have one or more of these seven causes: chance, nature, compulsion, habit, reason, passion, and
desire. (Aristotle)
Structure of this handbook
This manual can either be read from beginning to end or
used as guidance on specific topics. The reader is led step
by step though the planning, implementing and operational
stages of a decentralised composting scheme. The authors
have tried to generalise to a certain extent the experience
acquired. Special emphasis is placed on the following
“Tasks”
:
Task 1: Identifying Stakeholder Interest
Task 2: Assessing Target Community Interests and Land
Availability
Task 3: Data Collection
Task 4: Preparing a Business Model Plan and Financial
Projections
Task 5: Development and Design of Collection System
Task 6: Design and Construction of Composting Facility
Task 7: Operating and Maintaining a Composting Facility
Task 8: Marketing of Compost
Each “Task” is divided into a comprehensive section and
activities to allow frequent success rating and progress
assessment.
The Annexes contain further information on special issues,
such as scientific aspects of composting, blueprints of
facilities, contract templates, monitoring tables and
guidelines.
The authors invite the readers to contact them for further
information and clarification or to share their experiences on
composting with them.
8
Before starting a composting initiative, you must have a
clear vision of your objectives. If you have clear answers to
the questions below, it will be easier to convince others to
support your initiative. These questions may be asked by
decision-makers or other stakeholders concerned with the
project. Having clear answers available can help formulate
a common vision with important stakeholders, thereby
giving additional momentum to the start-up phase of a
composting scheme.
What are the driving forces behind a new collection and
composting scheme?
What do you strive to attain with the initiative? What is
your vision?
a clean neighbourhood?
poverty alleviation?
business opportunity and income generation?
reduced environmental pollution and increased
resource protection?
improved soil and nutrient management?
Since the visions of initiators may vary, general project
design considerations are necessary. Seeking clear
answers to the aforementioned questions is the first and
foremost step to successful implementation of a composting
project. A vision can be formulated on the basis of available
information of the current solid waste and prevailing
environmental situation.
Should the project comprise solid waste collection and
composting, or should it concentrate on composting
alone?
From which partners and types of partnerships could the
project benefit?
Knowing your environment
The composting scheme will always be embedded in a
complex and rapidly changing environment impossible to
control and difficult to predict. However, the better your
understanding of the external factors influencing your
initiative, the better you can adapt and react to changes.
Figure 1.1 lists some of the external factors influencing a
business or project environment. These can easily be
adapted to a composting initiative.
Activity 1: Determine the opportunities and threats
for your composting project
The “windows of opportunities” method allows collection
and analysis of the external and internal factors influencing
your initiative. Recollect the past in relation with the factors
listed in Figure 1.1 and determine their influence on your
decisions or initiative. Which external factors have led to
your success, and which have caused failures?
Such a past-oriented analysis allows predicting possible
future forces and their effects on composting and compost
sales. Which forces are opportunities and which threaten
your initiative? Bearing all these forces in mind, find ways to
influence them to your advantage. Determine their influence
on your business and develop scenarios on how to adapt
and react if they come into play.
Copy the matrix of figure 1.2 on a big sheet of paper and
enter the factors that have influenced your business/ project
in the past (left side). Which factors contributed to a success
or a failure?
Then, fill in factors that may influence your business in the
future (right side). Which of them are opportunities to the
project, which ones threaten your project?
9
Launching a Collection and Composting Scheme
Strong reasons make strong actions. (William Shakespeare)
Photograph 1.1: Common street scene in developing countries: micro
dumps
Photograph 1.2: A vision becomes reality. Former micro dump has been
converted into a small composting site
Examples:
Technological innovations: They strongly influence your project. Technical development can open up opportunities.
Sound and appropriate technology ensures high quality of your product and long-term success of your project.
Changes in farming practices: In the past most farmers adapted their practices after introduction and promotion of
chemical fertilisers. Now, the application of compost requires a change of these practices, which implies a certain effort.
This fact can be considered a threat, but it is a threat that can be reduced by certain activities. (e.g. through training
courses)
Climate is a natural force which may already have caused a failure of a composting project. (e.g. by heavy rainfall
saturating the composting windrows). Such climatic condition may pose a threat. Although, you cannot change the
prevailing climatic condition, you can adjust your technology (e.g. by roofing your composting site or providing a
drainage system).
Competing products: Cow dung or poultry manure may be competing products to compost, especially if they are
abundantly available at a low price. Such competing products pose a considerable threat. Given such a situation it may
be tough to influence the market unless you are able to provide compost at lower prices or with a better quality.
10
Figure 1.1: Factors influencing a business environment. These factors are hardly ever static but constantly changing. They may affect
your business directly or indirectly
Figure 1.2: Matrix to evaluate factors which determine success,
opportunities, failures or threats of a business or project. List any factor
having an influence on your project today and order them according to
the matrix
The following chapters provide guidance for project
implementation with clearly structured tasks, explanations
and activities. However, this handbook alone is not enough
to convey the necessary skills needed. Communication
skills, structured thinking as well as clearly defined
objectives and a flexible strategy will certainly help to gain
the support of other stakeholders.
Task 1
Identifying Stakeholder Interests
Identifying Stakeholder Interests : Task 1
Assessing Target Community Interests and Land Availability : Task 2
Data Collection : Task 3
Preparing a Business Plan and Financial Projections : Task 4
Development and Design of Collection System : Task 5
Design and Construction of Composting Facility : Task 6
Operating and Maintaining a Composting Facility : Task 7
Marketing of Compost : Task 8
13
For project implementation, it is essential for you to be
informed about the stakeholders and their interests. The
needs and aspirations of various stakeholders have to be
identified. Their willingness to accept and participate in an
improvement programme, involving waste collection and
composting, will depend on the priority given to solid waste,
awareness, and social cohesion of the community as well
as on affordability and willingness to pay for the waste
services rendered. All parties can benefit from a stakeholder
analysis. Sound data from the beginning contributes to
developing appropriate partnerships at a very early stage.
Partnership also means the sharing of benefits and risks of
a project, since awareness of the concerns and ideas of
others may prevent many pitfalls on the way to a successful
composting project.
Furthermore, to attain a long-term success and avoid legal
proceedings from opponents and pressure groups, it is
important to also consider the legislative framework (e.g.
environmental laws and land use regulations).
After undertaking the three subsequent activities, you will
be informed about:
relevant stakeholders involved in your project
potential project partners
potential communities for project implementation
potential composting sites in these communities
potential risks for your project and possible mitigation
strategies
Activity 1: Identify project stakeholders
Municipal stakeholders will first have to be identified to
assess their interests. A first overview of municipal solid
waste management and responsible stakeholders may be
obtained from secondary data such as newspapers and
reports. A stakeholder analysis helps to assess the key
stakeholders for project success, their roles and level of
participation during project implementation and operation. It
assists in understanding the different and conflicting
interests, as well as the potential for cooperation and
coalition with other stakeholders. A first overview can be
obtained with an analysis like shown in figure 1.3.
Stakeholders are identified and arranged in a triangular
matrix showing the three important organisational sectors
(private, public and non-governmental).
Table 1.1 contains a list of typical stakeholders, and the way
to assess and compare them. This list does not claim to be
exhaustive, as other stakeholders may be relevant in your
specific situation. The potential impacts describe the
positive (+) or negative (-) influence of a stakeholder on the
project. By formulating these positive and negative
influences in the column Remarks this table will already
allow a first risk assessment.
Two strategies for collection of relevant information from
stakeholders are briefly described as follows:
Firstly, the parties are invited to a meeting where the project
is presented and upcoming questions are discussed and
answered. Such an open discussion already reveals the
interests and concerns of the different stakeholders. It is
essential that all this information is treated with the same
importance, and that all stakeholders are allowed to express
their opinion. These statements should not be commented on
by the initiator, as the objective of this meeting is to collect
information and not to defend the idea behind the project.
Secondly, if not all stakeholders can be convened, consider
individual meetings with selected stakeholders. Give a short
presentation of your project and allow time for questions
and answers. This is more time-consuming but contributes
to a more effective information exchange. Stakeholders may
give important hints regarding project development or name
other helpful organisations and potential partners.
Task 1: Identifying Stakeholder Interests
Partnership means sharing risks and benefits. (Anonymous)
Figure 1.3: Triangular matrix for a first determination of potential
stakeholders
14
Waste Concern has developed a list of ten main questions
relevant to launching a composting scheme. These
questions need to be answered by all stakeholders. The list
of questions below can also provide guidance to both the
mixed stakeholder meeting and the individual meetings.
1. Collection: Does a primary house-to-house collection
exist in the municipality?
2. Source Segregation: Are the stakeholders familiar
with any waste segregation initiatives?
3. Support: Does the municipality show commitment to
waste management projects?
4. Land Availability: Is land for a composting site
available in the urban areas?
5. Road Conditions: How are the road conditions in the
proposed areas?
6. Community Awareness: Is the community aware of
waste management problems?
7. Knowledge: Do the stakeholders know of any
composting activities or technologies?
8. Composting Experience: Are persons or institutions
already familiar with composting?
9. Compost Demand: Is there a potential demand for
compost and by whom? What fertilisers are used? Is
compost already sold? Are marketing activities
available?
10. Data Availability: Do stakeholders have reliable data
on the amount of waste generated and its composition?
Activity 2: Identify environmental legislation and
land use regulations
Since national regulations vary significantly, they need to be
examined on a case-by-case basis. Prior to starting a
composting project, the laws and regulations that might
influence the project, need to be examined thoroughly to
avoid delays or even cancellation of the project. If
necessary, seek advice from a lawyer, an NGO or the
municipal authorities.
Environmental laws Determine the existence of a general
legislation supporting or prohibiting waste recycling and
reuse.
Solid waste management rules and regulations
Determine the existence of a general guidance
supporting or prohibiting waste recycling and reuse.
Land use regulations and urban planning strategies –
Determine the existence of regulations regarding the
construction and operation of waste treatment plants.
In some cases, the setting up of such plants in residential
areas is prohibited.
Agricultural laws – Determine whether agricultural waste
reuse is regulated in any way (e.g. quality certificates,
reuse limitations, pollution control).
Trade laws and regulations – you may have to register
the product if you want to market compost.
Stakeholders What are their interests?
What are their concerns?
Assess the potentially
positive (+) or
negative (-) impacts
Remarks
Ministry of the Environment Reaching targets
Elected local representatives Timely delivery of visible services
Municipal authority (waste department) Reaching targets
Operational control
Municipal department responsible for parks
and green areas
Treating the park trimmings
Using the compost
Fertiliser associations Promoting fertiliser
Developing new products
Community organisations Improved access to SWM services
Improved health and opportunities
Financial burden
Women and children in the communities
concerned
More time for other activities
Job opportunities
Men in the communities concerned Improved health
Job opportunities
Waste pickers and sweepers of the
informal sector
Decreased access to recyclables
Job opportunities
NGOs / CBOs Improved hygiene situation
Job opportunities for the poor
Improved well being in the neighbourhood
Donor agencies Short-term disbursement of funds
Visible poverty alleviation
Table 1.1: Matrix for a stakeholder analysis
Activity 3: Identify potential marketing options
This activity is only the first step of the development of a
marketing strategy for compost. Though Task 8 (Marketing
of Compost) is at the end of this book, we recommend
reading it after finalising this Task. Task 8 introduces the 4
Ps of marketing (Product, Price, Place, and Promotion) and
provides additional structured information how to analyse
markets and elaborate a strong marketing strategy. This
knowledge should be kept in mind when reading the
following chapters of this handbook.
The main objective of a waste collection and composting
project is an environmentally friendly and socially
acceptable removal of waste. Composting is one treatment
option among many, and only viable if a sound financing
system is guaranteed. Such financing systems may consist
of subsidies, user fees, and income from the sale of
compost or a combination of all the options mentioned.
However, the demand for compost is of key importance.
There are many markets for compost beyond its typical use
as soil amendment or fertiliser. However, identification of
these markets and how they should be approached have to
be thoroughly clarified. At this stage of the project, only
general questions on the potential marketing options need
to be answered to determine whether composting can be a
financially viable project.
Different customers and marketing options for the final
products of the composting scheme should be identified
during stakeholder analysis. A composting scheme can
have revenues from the sale of compost and recyclables,
and potential incomes from both sources need to be
assessed. A market study is not difficult to conduct but
requires some planning and time. You need to collect
information on:
A. Your existing customers and potential customer
groups
to maintain and improve your product and service, to
guide your promotional efforts and develop new
compost products or new services (e.g. delivery,
advice on use).
B. The competition and competing products
to help you assess the probabilities of success and
failure, give you ideas to improve your products and/or
services, and find a way to increase your share of the
market or to reach other customer groups.
C. The environment
comprising economic, social, political, and natural
forces influencing the composting business. Collecting
information on the environment allows you to stay
abreast of and respond to particular trends or events
affecting your business. Awareness of a drop in
interest rates or new waste management policies is
important to assess their positive or negative effects
on your business.
The information necessary for your analysis can be
collected from two main types of data sources:
Primary sources, providing firsthand information,
originate from key informants such as existing and
potential customers, competitors, decision-makers or
experts. Although collection of this kind of data can be
costly and time-consuming, it can also be the most
valuable, as it is the most up-to-date and specific
information you can obtain.
Data from secondary data sources has already been
collected by others. It originates from trade journals,
government publications, statistics, reports from local and
external development agencies or NGOs or even surveys
conducted by other companies. This data can provide
valuable information on your customers’ needs and
business environment.
Potential customers must either need or want (or both)
compost, and be capable and willing to pay for it. Mention
should be made that not all these components are
necessary to qualify for a potential customer, however, the
ability to pay for compost is essential.
Where could compost potentially be used and for what?
Who are your potential customer groups and what are
their compost needs?
What assumed potential quantities might each customer
group need (potential market demand)?
How much are they able and willing to pay?
What are the existing alternatives to compost and how
much do they cost (e.g. manure, soil, sludge)?
Prepare a list of potential customers and visit them.
Investigate their needs regarding compost quality and
quantity required, as well as their willingness to pay. The
following box contains an overview of potential customer
groups known to require compost. The customer groups can
be divided into bulk markets which demand high amounts
and are not willing to pay high prices and cash markets
which pay higher prices but require less amounts of
compost. However, the list is not complete, since the local
context may reveal several additional niche markets.
Typical compost customer groups
Bulk market
urban and peri-urban agriculture (farmers)
rural agriculture
viticulture (wine)
green space management (parks, zoos, sport arenas)
forestry
landfill rehabilitation, mining rehabilitation
Cash market
horticulture (flowers and trees)
home gardening
vegetable gardening
hotels and company premises
landscaping, land development
fertiliser companies (retailers)
industrial use (biofilters)
15
Figure 1.4 shows average compost market figures from
Switzerland. In this case, agriculture demands 67% of
produced compost and is the main market for compost.
However, compost has a low value in the agricultural sector
and only little profit can be gained.
Figure 1.4: Average distribution of compost to different customer
groups. Assessment of 13 Swiss compost producers (from Schleiss
(2002): Compost Marketing in Switzerland)
An example of how to characterise a potential compost
customer group is given in table 1.2, with focus on the
horticulture market segment in an urban setting. It describes
its compost use and most typical requirements regarding
compost quality and quantity. Such fact sheets for each
customer group can be established from your stakeholder
analysis. They constitute the basis for assessing the overall
potential market demand.
Consider your own situation and think whether compost
could either be sold by your own distribution network or
through retailers, which take over distribution of the product
(e.g. a fertiliser company). In the latter case, the partner
would be the bulk customer of the composting scheme. In
some cases, the end user could also be a bulk customer,
e.g. if the municipality is interested in the product and willing
to pay for it. Both strategies have inherent advantages and
disadvantages. The decision is strongly dependent on
compost demand and location of the different potential
customer groups.
With this information, it is possible to judge if a composting
scheme is feasible in your local context. All potentials and
risks influencing the project should be known to allow
development of mitigation strategies to tackle potential
risks. Be aware that markets are very dynamic. It is crucial
for a business to keep track of market developments in
order to remain competitive.
The current conditions may sometimes be unfavourable for
setting up a composting scheme, such as the lack of
demand for compost due to the availability of other cheaper
fertilisers, constant water shortages or lack of land. In such
cases, other waste management options must be
developed.
Now, you are invited to have a closer look at Task 8 of this
handbook.
16
Customer Group: Horticulture/Nurseries
Geographic location Urban and peri-urban area, frequently along roadsides and on vacant plots.
Uses Compost is used as soil substrate and potting mixture for container plants such as trees, flowers, ornamental
plants, and seedlings.
Quantity As aforementioned, compost alone is not recommended for use as soil substrate, however, mixed with sand
and/or soil it gives an excellent potting mix. Potting soil typically is amended with 5- 40% of compost (by
volume).
Quality Seedlings require well-matured and finely sieved compost. Less mature compost can be used as mulch for
adult plants.
Ability to pay This customer segment usually draws a regular but not necessarily high income from a continuous and
reliable market. Thus, the ability to pay is assumed to be average.
Willingness to pay Willingness to pay is dependent on the level of awareness and knowledge on how to use compost. Self-made
compost by the nurseries or animal manure may compete with your product and reduce willingness to pay.
Purchasing behaviour Seasonal fluctuations in purchase are generally expected.
Competing products used
Self-made compost, animal manure, peat, subsoil.
Estimated potential X number of nurseries have been identified in the city. The annual demand of a nursery is estimated at Y tons
of raw compost. Data is based on local business statistics and own observations. (multiply the X value with
the average of all Y values.
Table 1.2: Example of a compost customer fact sheet
Task 2
Assessing Target Community Interests and Land Availability
Identifying Stakeholder Interests : Task 1
Assessing Target Community Interests and Land Availability : Task 2
Data Collection : Task 3
Preparing a Business Plan and Financial Projections : Task 4
Development and Design of Collection System : Task 5
Design and Construction of Composting Facility : Task 6
Operating and Maintaining a Composting Facility : Task 7
Marketing of Compost : Task 8
After identifying the potentials, risks and relevant
stakeholders and deciding to go ahead with the
implementation of the composting activities, focus is placed
on selecting the target community for the composting
scheme. If the decision-makers propose several locations
for the composting site, these should be visited and the
project presented to the community and beneficiaries. The
most appropriate way is to hold a question and answer
meeting to allow all participants to state their opinions and
concerns about the project (Task 1).
After finalising the subsequent activities you will be aware
of:
how to approach and inform the community
how to evaluate the willingness of the community to
participate in the project
ideas and concerns of the beneficiaries
local conditions in the target area
community willingness to cooperate and to what extent
important criteria required to identify potential
composting sites in these communities.
To conclude, you know whether this community offers a
suitable location for your composting scheme.
Participatory approaches have been widely applied in the
fields of water, environmental sanitation, hygiene, and
waste management. Experience has shown that community
involvement can lead to wide-ranging benefits:
If people understand a problem, they are more willing to
solve it.
Communities can and should determine their own
priorities in dealing with the problems they face.
People solve their own problems best in a participatory
group process.
The enormous depth and scope of acquired community
experience and knowledge can be used to bring about
changes and improvements.
Programmes with community involvement therefore aim at
involving all members of a society in a participatory process
of assessing their own knowledge, investigating their own
environmental situation, visualising a different future,
analysing constraints to change, planning for change, and
implementing change. Their interest and motivation to
participate and contribute influence the organisational setup
of the project (see Task 4).
Activity 1: Organise a community meeting
To establish a composting unit with community support,
organise meetings in the community with the largest
possible number of different stakeholders such as:
Members of the community, male and female, as well as
youth and children
NGO representatives, active in this community
Political and administrative representatives of the
community
Existing waste workers (collectors and recyclers)
servicing the area
Municipal waste management staff.
Announce a community meeting and invite all interested
parties. Make sure that all the interested stakeholders are
able to attend the meeting (see Table 1.2 (Matrix for
stakeholder analysis) in Task 1). Openly discuss the
advantages and disadvantages of the existing waste
management system at the meeting.
What problems have been identified in relation to waste
management? What causes the problems? Who sees
them as important?
Do stakeholders see any opportunities and potentials for
improvement of the waste management system?
Is there a tradition of community-based action, and what
are the opinions on this approach?
Are primary stakeholders aware of the need to change
the common practices with the new approach and
technology?
Which problems are seen as high priority? Do the
priorities of stakeholders differ?
Is composting a known practice? What information is
necessary?
Is land available within the community for the composting
site in the community?
The next step is to present the scope and idea behind the
project. Share the vision with the community but also inform
them on how waste management and composting can be
managed in practice. Describe the tasks and duties awaiting
the community if a composting plant is set up. Allow
questions and provide open answers and clear
explanations. Do not defend the project, as it may show
signs of weakness.
19
Task 2: Assessing Target Community Interests and Land Availability
Structures influence processes, processes change structures (Anonymous)
Important Questions
Make sure the following issues have been raised during
the meeting. Reflect on the answers voiced by the
different stakeholders:
Do community members have the required confidence
and skills to engage effectively in participatory
processes and partnerships?
Are traditional institutional structures available, have
they been used in the past and could they be used
again? Will women be represented?
Who makes decisions in the community, and how will
local power structures be affected by the project?
To what extent is the community interested in
contributing labour and engaging in operation and
maintenance? Will this affect its status? Will it
contribute to its income?
How will the project increase the responsibilities and
workload of certain groups? Which groups need
support and what kind?
Will some groups be excluded from or negatively
affected by the project (e.g. waste pickers?). How can
this effect be overcome?
Have all the target community members, particularly
those affected by poverty or disadvantaged by their
status in society, been able to voice their opinions?
Have the different needs of women, men, older and
younger people, and those with different abilities been
taken into account?
Have women and men expressed their views on the
siting of the plant and possible institutional
arrangements for operation and maintenance?
Has the issue of financial costs for the households
been raised?
If user charges pose a problem for poorer households,
what arrangements have been suggested to overcome
this problem?
Have women and men different responsibilities
regarding household budgeting? Have they been
taken into account when assessing willingness and
ability to pay?
Independent from the organisational set up, the
responsibilities and roles of the local community should be
clarified. Experience reveals that a committee selected by
the attending community members helps to establish
ownership and responsibilities in the community.
The committee
will be the authority through which the community can
present its ideas and objections during project
implementation and operation.
will subsequently discuss all issues with the project
coordinator and/or service provider and with the
responsible municipal person to find a feasible solution.
will determine whether the residents regularly pay their
contributions for door-to-door waste collection.
will determine whether the waste collectors perform their
assigned jobs regularly and adequately.
will also raise the environmental awareness of other
community members.
If the community agrees to share the aforementioned
responsibilities, go on to the next assessment step.
Activity 2: Conduct a structured survey using a
questionnaire
A community meeting, like the one previously described, is
the first step to acquiring knowledge of the needs and
priorities of the beneficiaries. This rather qualitative
information has to be further quantified. This additional
information (e.g. satisfaction with the current collection
system or willingness to pay for an improved system) allows
you to design your collection service and composting
system. Remember that the first priority of the community is
most probably a reliable waste collection service. If the
community is satisfied with the service, it is far more likely
to support additional measures like composting.
To obtain conclusive results regarding future system design
and to avoid biased answers, the survey should cover a
certain number of households randomly selected from
among all income groups of the community. Furthermore, it
is important to consider the gender issue. Make sure that
you obtain a balance of women and men who are
interviewed.
The calculation of the adequate number of households for
a survey is quite complex and time consuming. Table 2.1
provides already calculated sample sizes under pre-
defined sampling errors for household surveys. This table
can give guidance on the number of households to be
assessed to obtain reliable results. However, selection of
sample size and acceptable sampling errors depend on the
time and manpower available for such a study. For more
background information about statistical analysis have a
look at Annex 2.
20
Table 2.1: Calculation of adequate sample sizes for household
surveys
If the total number of household lies between two given values,
choose a sample size between the corresponding sample size
values (interpolation).
The relevant questions for a household survey may differ
from one case to another. Yet, the following nine questions
provide guidance through this task. They can be revised
and detailed allowing a categorisation of answers. Annex 3
shows a questionnaire for a community survey related to
solid waste management.
1. Are you satisfied with your current solid waste
management system (temporary storage and collection)
in your community?
2. Does the municipal administration provide a solid waste
management service in your area?
3. Do you think the current waste management system in
the area pollutes the local environment?
4. Which factors (caused by inappropriate waste disposal)
are responsible for local environmental pollution?
5. Who collects and disposes of your household waste?
6. What improvements of waste collection system would
you like to see applied?
7. If your waste is collected directly from your house, how
should it be collected?
8. How often and at what time do you want your waste to
be collected?
9. You may have to pay a fee if your waste is collected
directly from your house. How much are you willing to
pay monthly for the system?
Analyse the completed questionnaire by counting the
answers given and express them as a percentage of the
total number of answers. If you did not have the means to
do a comprehensive survey with the number of households
suggested in Table 2.1 randomly divide the questionnaire in
two groups and analyse them separately. If the results diver
from each other significantly, additional interviews are
required. The box contains possible results of such a
survey.
Example:
The results obtained indicate that 80% of the interviewed
households feel that local pollution is caused by
overflowing public bins as a result of the public emptying
services not being frequent enough and a lot of waste is
being left behind. The questionnaires also reveal that
about 60% of the households interviewed favour a house-
to-house collection, while 40% would prefer to place their
bins in front of the house at a certain time. 90% of the
households are willing to pay an additional fee for that
service.
This information will allow you to adapt your project to
community needs. Firstly, the collection must be improved.
Secondly, composting will be justified, as it will clearly
reduce the amount of waste in the temporary public
storage and prevent them from overflowing. Thirdly, the
results also clearly reveal that cooperation with the
municipal workers is essential, as they are responsible for
emptying the public storage bins and waste transportation.
The households in the community will also judge your
performance by the cleanliness of the area!
In some cases, the household-favoured system may not be
clearly defined. Consult the “Committee” or invite the
community to another meeting to discuss the results and
jointly decide on a system. A consensus at this stage of the
project avoids problems during implementation.
Activity 3: Assess land availability and visit
proposed sites
During the first community meeting, the important aspect of
land availability has to be discussed with the attending
stakeholders. Either the municipal decision-makers have
already proposed plots or the community itself proposes
land for the composting site. However, since land use,
especially for waste treatment purposes in residential areas,
is always a very sensitive issue, give special attention to
that issue.
Given the often prohibitive prices of land in urban areas, it
is essential to conclude special agreements to obtain this
land at low rents or even free of charge. Ideally, the
municipal authority should make land available as the future
waste collection and composting services will contribute to
21
Required sample size allowing a 95%
confidence level
Total number of
households in the
community
Low Medium Still
acceptable
sampling
error
sampling
error
sampling
error
100
250
500
750
1,000
2,500
5,000
10,000
25,000
50,000
100,000
1,000,000
100,000,000
50
152
217
254
278
333
357
370
378
381
383
384
384
50
110
141
156
164
182
189
192
194
195
196
196
196
49
70
81
85
88
93
94
95
96
96
96
96
96
municipal service delivery. Experience shows that suitable
plots of land can be found in almost all communities.
Listen to the proposals of the stakeholders, as they are
familiar with the local conditions. However, the following
areas are also worth a closer look if they have not been
discussed already:
privately owned land belonging to organisations
unauthorised micro dump sites (which have to be
cleared, but residents will appreciate a change)
corners in a green area (park or strip along a road)
unused public spaces.
Organise a visit to these sites with the stakeholders
(municipal officers and/or Community Action Committee).
During the visit, focus on the following important selection
criteria and discuss them with the stakeholders.
Proximity to the waste generation source to ensure
frequent delivery of sufficient fresh waste at low cost. This
is especially relevant when determining the number of
staff and vehicles required for the waste collection
service.
Water supply is a prerequisite for a composting site. The
water should meet the chemical quality standards (low in
toxic compounds, heavy metals and salinity).
An electricity supply is desirable as it facilitates some
composting steps, however it is not essential.
Sites should not be located at the edge of wetlands or
flood plains.
Roads for waste delivery and pickup of residues should
be well maintained and easily accessible throughout the
year.
Densely populated neighbourhoods and areas where
adjacent land users may object to a composting plant
should be avoided.
Adequate green buffer zones (for building a fence or
planting trees), separating the composting plant from the
neighbourhood should be available.
Composting plants should be located downwind
(considering the prevailing wind direction) from
residential areas.
The land of the composting site should be located on a
slight slope and the soil shold be appropriately grades to
avoid water logging and facilitate proper drainage.
A composting plant with a daily capacity of three tons using
a windrow composting system requires a site with an area
of about 1000m
2
. A composting site using the box technique
requires about 800m
2
of land. Task 6 (Design and
Construction) will give detailed information on the most
efficient way to set up the composting plant. However, it is
important to consider the individual local conditions.
After finding an appropriate plot for the composting site, a
written and signed agreement with the responsible persons
should be established. Experience with existing decentra-
lised composting plants has revealed that there will always
be people who do not agree with the composting activities.
The various reasons range from fear that nearby land will
drop in value, fear of odour and vermin or other financial
and political interests. Hence, a written agreement such as
a Memorandum of Understanding (MoU) is important to
ensure the continuity of the project. Formulation of the MoU
strongly depends on local conditions and on the decision-
makers. A generalised template for a MoU is shown in
Annex 5. The template provides guidance on aspects to be
mentioned and discussed. But it needs to be adapted to the
particular local conditions.
Further reading
GTZ (2005): Improvement of Sanitation and Solid Waste
Management in Urban Poor Settelments, GTZ, Eschborn,
Germany (order or download from www.gtz.de/solid-waste-
management)
22
Task 3
Data Collection
Identifying Stakeholder Interests : Task 1
Assessing Target Community Interests and Land Availability : Task 2
Data Collection : Task 3
Preparing a Business Plan and Financial Projections : Task 4
Development and Design of Collection System : Task 5
Design and Construction of Composting Facility : Task 6
Operating and Maintaining a Composting Facility : Task 7
Marketing of Compost : Task 8
The activities of Task 2 have provided information on
perceptions and needs of the community concerned, while
Task 3 mainly concentrates on technical information
necessary for the composting project. The data collection
concentrates mainly on technical aspects of solid waste
generation and management. One could argue that this
technical information is also relevant from the start, but it is
easier to obtain technical information if the local social
relationships are well understood and first contacts
established.
After finalising the activities of Task 3 you will be familiar
with:
the amount of waste generated in the selected
community
the waste components and other important waste
characteristics
the natural environment of your community
Knowledge of all these aspects is important when
selecting the right waste collection vehicles and planning
the design of the composting scheme.
Activity 1: Determine the solid waste generation
If you are lucky, you will find reliable data on community
waste generation in evaluation reports of NGOs,
consultants or municipalities. In some cases, the
information from neighbouring communities may also be
relevant if the standard of living does not significantly differ
from the one in the selected community. However, using
“per capita” waste generation figures from secondary data
along with average household size will be less reliable than
information from first hand waste analyses. Secondary data
is often of a more aggregate nature and does not include
the local determining factors. Hence, it is advisable to
conduct a own study for the target community.
The main questions to be answered are:
How many households does the community comprise?
How much waste is generated totally?
What is the average daily waste generation rate of a
household in the project area?
How much organic biodegradable material is contained in
this waste?
How much recyclable material is contained in the waste?
What types of recyclable material are present?
A direct measurement of the average household waste
generation is necessary if such data is not available. A first
rough estimate can be done by assessing the existing
collection service, if already available. To obtain more
reliable information, the number of households (sample
size) surveyed is equal to the sample size identified in
Activity 2 of Task 2 (community survey). This activity
requires additional time and staff and has to be planned
thoroughly.
Organise a one-week survey of a sufficient number of
households randomly selected in the community. Inform the
households about the purpose of the survey and ask them
to collect their waste in the bags or bins provided and
collected by the survey staff. If possible, ask for municipal
support and involve public workers in the study.
Prepare a short form, defining each surveyed household
with an identification number, address and the number of
household members. Ensure that each collected bag is
labelled with the identification number.
Discard the waste on the first day without weighing it
because you do not know how many days the waste has
been waiting to be collected. If there is not a regular
collection service is a good idea to discard the waste of the
second day also because residents may be taking
advantage of the collection service to clean out their yards.
Include the weekend and at least one day before and after
the weekend in case there is a significant difference in
generation rate at the weekends.
Collect the waste bags from the households on a daily basis
and take them to a central point where they are weighed
separately. (Since the waste analysis continues with Activity
2, do not dispose of the waste!). Calculation of the average
waste generation per household can be simplified by adding
all the measured weights and dividing the result by the
number of households (sample size). By dividing the result
with the average number of household members you will
obtain the per capita waste generation.
capwaste: per capita waste generation (kg/ day)
hhwaste: average waste generation of one household
(kg/day)
hh: number of households surveyed
hm: average number of household members
25
Task 3: Data Collection
We can have facts without thinking but we cannot have thinking without facts (John Dewey)
Caution: The survey merely reflects the waste generated
by the community over one week only. Waste generation
and composition may vary considerably depending on
holidays or seasons. Though you can use the gathered
information to go ahead with the project, it is advisable to
conduct an additional survey during a different season.
Future projections
The procedure for data collection and calculation focuses
on the current situation. It is likely that the quantities of
waste will increase in the coming years as the population
rises and habits change. However, this change should not
be of concern unless large numbers of people are moving
into the neighbourhood. Annex 6 provides a brief
introduction on how to calculate future projections.
After collecting all this information, you will certainly want to
know how many households can be covered by the project.
Given your planned composting plant size (e.g. three tons
per day) and the aforementioned information, you can
easily calculate the number of households covered by the
plant.
hhs: number of households serviced
capacity: intended plant capacity (kg/day)
hhwaste: average waste generation of one household
(kg/day)
bio: biodegradable fraction (% of household waste
generation, wet weight)
Example: Your aim is to set up a plant of three-ton organic
waste processing capacity per day. Based on your survey,
the average household waste generation rate is three kg
per day with a biodegradable fraction of 75 %. Based on
the following calculations, the number of households you
will service is approx. 1330:
Collection of additional organic waste from special waste
producers (e.g. markets) will reduce the amount of
households serviced by the given plant capacity.
Activity 2: Analyse the solid waste composition
Waste characteristics can be generally divided into two
groups:
The physical waste composition provides information
on waste contents such as organic and inorganic waste
or recyclables. Furthermore, it includes moisture content
and density. This information facilitates the decision on
vehicle design or sorting efficiency.
The chemical waste composition covers information on
carbon and nitrogen content.
1. Analysing the physical waste composition
Determination of waste composition is conducted with the
same waste like collected under Activity 1. However, it is not
necessary to analyse the total amount of collected waste.
Only 100 kg of waste is analysed. This amount is obtained
through the so called quartering technique:
Pile the waste of all bags into a large heap and mix it
thoroughly. Divide it into four quarters and keep just one
quarter. If this amount is still too large, repeat the mixing and
divide it again until only 100 kg of mixed waste are left. This
representative sample is then sorted into three fractions,
namely:
a. organic waste (biodegradable waste)
b. recyclables with market value (e.g. glass, plastic,
metal)
c. inorganic waste and residuals
Weigh the different fractions and calculate the relative
municipal waste composition. Annex 6 provides examples
of all these calculations. The examples base on an existing
case in Bangladesh. Furthermore, it describes an
alternative technique for reducing the waste to be
assessed.
Density and moisture are two important waste parameters
and need to be assessed. They are relevant for designing
the collection containers and vehicles.
Density
Loosely fill the collected waste into a container of known
volume (10–50 litre) and weight. Weigh the container and
register the result. The density can be calculated using the
following equation:
Waste density in developing countries usually varies
between 0.4 and 0.6 kg/l and is strongly dependent on the
organic waste fraction and moisture. The higher the
moisture or organic waste fraction, the higher is the waste
density.
Moisture
Moisture can be measured rather easily: take a
representative sample of the mixed waste collected (e.g. 10
kg) and register the weight (m
start
). Spread the waste on a
plastic sheet in the sun and let it dry for 24 hours. Make sure
that neither animals nor rain disturb the drying process.
Reweigh the dried waste, register the result and let it dry for
another 24 hours. Repeat the procedure until the weight is
almost constant (m
end
). The loss in weight is equal to the
26
moisture content and can be calculated as follows:
Significance of the moisture content for composting is
explained in Task 7.
2. Analysing the chemical waste composition
Now focus is entirely placed on the organic fraction of the
sorted waste. In an efficient composting process, the
carbon/nitrogen ratio of the waste should range between
25:1 and 40:1. This variation indicates a possible variation
in waste compositions. Carbon (C) and nitrogen (N)
measurement of the organic waste fraction is expensive
and requires professional equipment and knowledge.
Initiators are often unable to finance such expensive
preliminary analysis. This handbook will thus provide
guidance on how to assess the C and N content through
visual examination. The table below contains examples of
organic waste and their typical range of C/N ratio.
Table 3.1: Waste types and their C/N ratios
* read: C/N ratio ranges from 2:1 to 4:1
On the basis of this table, characterise type and amount of
waste surveyed in the target community. Household waste
mainly contains kitchen and garden waste. As shown in the
table, the C/N ratio of this waste is often already ideal for
composting. However, in some cases or during certain
seasons, the incoming organic waste either needs a carbon
or a nitrogen supplement prior to composting. Task 7
(Operation and Maintenance) and Annex 7 (Science of
Composting) provide additional information on waste mixing
ratios.
Activity 3: Assess topography and road conditions
The choice of waste collection vehicle is also dependent on
local topography and road conditions. No general
recommendations are possible as the choice mainly
depends on the local conditions and cultural backgrounds.
However, the following three examples illustrate the
importance of that issue:
If the community is located in a hilly area, handcarts and
rickshaws are unsuitable as the loaded vehicles become
too heavy for the collectors. This is especially relevant if
the composting site is uphill from your community.
If the settlement structure is very scattered, a motorised
rickshaw bridges the collection distances much faster
than a handcart.
If the roads are not paved but merely covered with sand,
the wheels have to be stronger and wider. This simple
measure avoids time losses due to stuck vehicles.
The types of vehicles used for transporting goods and waste
already indicate the types of locally available vehicles.
Further information on advantages and disadvantages of the
different vehicles is provided in Task 5.
Further reading
Agency for Environment and Energy Management (ADEME)
(1998): MODECOM
TM
- A method for characterization of
domestic waste. ISBN 2-86817-355-1
Agency for Environment and Energy Management (ADEME)
(1998): MODECOM
TM
- A method for characterization of
domestic waste. Addenda to the MODECOM
TM
methodological guide. ISBN 2-86817-355-X
27
Waste Type C/N
Ratio*
“Green”
High in
Nitrogen
“Brown”
High in
Carbon
Cow/chicken manure 2-4 X
Vegetable waste 11-13 X
Grass cutting 15 X
Fruit waste 20-49 X
Household waste 34-80 X X
Leaves 40-80 X
Park waste: twigs/ branches,
wood chips, saw dust
200-800 X
28
Task 4
Preparing a Business Plan and Financial Projections
Identifying Stakeholder Interests : Task 1
Assessing Target Community Interests and Land Availability : Task 2
Data Collection : Task 3
Preparing a Business Plan and Financial Projections : Task 4
Development and Design of a primary Collection System : Task 5
Design and Construction of Composting Facility : Task 6
Operating and Maintaining a Composting Facility : Task 7
Marketing of Compost : Task 8
The data collected in Task 3 contributes to the development
of an appropriate management model in Task 4.
Furthermore, it also provides guidance on determining
financial viability of the business or project and the setting
up of a contract with potential project partners.
After finalising the activities under Task 4 you will have
learned to:
develop an appropriate management model to
implement the composting project
assess the financial viability of your project by
calculating the benefit-cost ratio
set up a contract or agreement with your project
partners
Activity 1: Develop an appropriate management
model
There is a wide range of different solid waste management
models and business partnerships. The four management
models for decentralised composting schemes described in
this book proved to be applicable in various countries. Their
usefulness is, however, strongly dependent on local
conditions and cultural backgrounds. All the models
described are based on some degree of partnership
between the municipality, the community and/or private
entrepreneurs. Any partnership model applied should,
however, be based on common objectives, balanced power,
clear agreements, mutual trust and understanding.
Therefore, make sure to crosscheck the models described
before developing the most appropriate for your needs.
All models described below have in common the
municipality’s benefits from an overall cost reduction of their
waste management activities (mainly transportation and
disposal) through a more decentralised reduction and
treatment of waste.
1. Municipally owned – municipally operated
Decentralised composting schemes of this kind are
planned, implemented and operated by a municipal division.
The schemes form an integral part of the existing municipal
solid waste management system. The thrust for its
implementation comes from an integrated municipal policy
for improved urban solid waste management. Such a policy
foresees a clean and hygienic urban environment as a
result of the reduction or recycling of waste as close to its
source of generation as possible. Cost recovery for the
composting schemes is not a prerequisite, but desirable.
The major aim is to achieve benefits for the entire solid
waste management system by lower transport costs,
improved landfill management and reduced quantities of
waste to be handled. Furthermore, organic waste
transformed into compost can contribute to generating a
certain income for the city. Although this model assumes
that decentralised composting is managed entirely by a
dedicated municipal team, cooperation with residents is
indispensable.
2. Municipally owned – community operated
In this model, the decentralised composting schemes are
planned and implemented by the municipality, however,
their operation and maintenance is handed over to the
benefiting community. Ideally, the community is invited to
come forward with own proposals and to participate in the
planning and implementing processes. Apart from
composting, this model often comprises primary waste
collection and is frequently applied in low-income urban
areas. In many instances, an intermediary, such as an NGO
or a composting advisor, is required to provide or develop
the technical composting and management skills within the
community. The main incentive behind this model is to
reduce secondary collection or transport costs by reducing
and treating waste as close to its source as possible.
Furthermore, it improves primary waste collection without
significantly increasing municipal operation efforts and
creates local employment opportunities. The operation and
maintenance costs are covered by additional service
charges paid by households and by the profits from the sale
of compost. This model requires a written contract between
municipality and community or, alternatively, with an NGO
as intermediary.
3. Municipally owned – privately operated
As in the previous models the municipality plans and
implements decentralised composting programmes.
Composting plants are constructed on municipal land and
the system is owned by the municipality. Operation and
maintenance of these schemes is, however, contracted out
to the private sector or NGOs by open bidding. The call for
tenders already stipulates the rights and responsibilities of
the future operator and forms the basis for a later contract
between the partners. The contract regulates the duration of
the arrangement, required maintenance, rents, sharing of
profits, and waste collection fees. Operation and
management costs have to be covered by the private
contractor through the revenues of the project. The aim of
such a project is to raise additional capacity in solid waste
management (SWM) by involving third parties like the
private sector, thereby contributing to additional know-how
and finances to improve the entire solid waste management
system. Depending on contract design and the local
compost market conditions, this model has the potential to
foster profit-seeking projects in SWM. Waste Concern
promoted this model during a UNICEF-supported
programme in 14 towns of Bangladesh. The municipality
tendered primary waste collection and composting schemes
in defined communities. The private operators received
permission to use existing composting plants for five years
31
Task 4: Preparing a Business Plan and Financial Projections
Taking calculated risks is quite different from being rash (George S. Patton)
without paying rent or sharing the revenues from waste
collection and composting. However, without the
involvement of funding agencies, rental rules and
regulations have to be included in the contract.
4. Privately owned – Privately operated
This decentralised composting model is based on a profit-
seeking approach, which presupposes that the income from
waste collection fees and compost sale is sufficient to cover
all the costs of a decentralised composting plant. Land and
infrastructure are financed and managed by the private
sector. However, if the private company still requires a
permit to collect waste from defined municipal areas, it
cannot act independently but has to conclude an agreement
with the municipality. In Khulna, Bangladesh for instance,
the private organisation RUSTIC constructed a composting
plant on private land to process 20 tons of waste per day.
The Municipality of Khulna granted a permit to collect waste
from households and markets. Prior to the construction of
the plant, RUSTIC had to apply for an environmental
clearance certificate from the Department of Environment. A
possible variation of this model allows a private
entrepreneur to set up a composting plant on public land.
Though the municipality provides the land, the full financial
and operational responsibility remains with the private
entrepreneur. The municipality grants a long-term lease for
that land (e.g. ten years) to ensure a long-term operation
and, thus, appropriate returns on investments.
Table 4.1 lists these models and briefly describes their
advantages and disadvantages.
ALM – A municipal-community partnership in
Mumbai, India
A slightly different example for a municipal-community
partnership is found in Mumbai where the municipality
has been successfully assisting neighbourhood schemes
known as Advanced Locality Management (ALM). The
municipality of Mumbai supports community initiatives
(involving groups of approximately 250 households each)
to improve the living conditions in their own
neighbourhoods. For many of them, waste management
is a central aspect. The programme provides non
monetary services to the active neighbourhoods. For
example, the community advisor discusses community
plans with the neighbourhoods and organises temporary
cleaning equipment or designates abandoned open
spaces as waste collection or composting sites. Of the
670 registered ALMs, roughly 280 collect and compost
their organic waste. An additional fee paid by participating
households finances waste collection, and the compost
is, in turn, sold directly to the neighbourhood at a low
price.
32
33
Options Characteristics Main Actor(s) Role of City Government or
Municipality
Advantages Constraints
Model 1
Municipally owned -
Municipally operated
Integrated into the existing
municipal SWM system and
focused on reducing waste
which otherwise has to be
transported and disposed of in
landfills.
Cost reduction through lower
transport and disposal costs.
Municipality
Introduces recycling and
composting into the SWM policy.
Implementing agency.
Composting is an alternative treatment
system, which can be integrated into the
existing system (waste collection,
transport, disposal).
All composting sites can be centrally
controlled.
City gains valuable soil conditioner to
maintain parks and green areas.
Financial constraints due
to the low priority given
to SWM projects.
Operating efficiency and
marketing potential may
not be fully exploited.
Lack of coordination
between departments
regarding the use of the
compost product.
Model 2
Municipally owned -
Community operated
Benefiting community is
involved in the management of
primary waste collection and
composting.
Non-profit seeking model.
Cost reduction through lower
transport and disposal costs.
Municipality
Local community
NGOs
Introduces recycling and
composting into the SWM policy.
Implementing agency.
Supports communities in finding
composting sites and develops a
proper system for waste collection
and disposal of residues.
Provides support funds for
construction of composting plants
and the setting up of a primary
waste collection.
Alleviates the municipal burden of SWM
through community inputs.
Improvement of solid waste
management scope through voluntary
participation.
Clear contracts ensure reliable
partnerships with community groups.
Creates new jobs in the
neighbourhoods.
Lack of community
awareness and interest.
Need for a reliable
informal leader among
the community.
Highly complex
management.
Model 3
Municipally owned -
Privately operated
Benefiting community is partly
involved.
Profit seeking model is possible.
Requires at least full cost
recovery (from fees and
compost sales).
Cost reduction through lower
transport and disposal costs.
Municipality
Private sector or
NGO
Introduces recycling and
composting into the SWM policy.
Implementing agency.
Selects composting sites,
constructs plants (investments);
develops a proper system for
waste collection and disposal of
residues.
Contracts out the operation and
maintenance. Monitors
performance of contractors.
Alleviates the municipal burden of SWM
through private sector participation.
Provision of additional funds and know-
how through private investors.
Clear contracts ensure reliable
partnerships with private entrepreneurs.
Creates new jobs in the
neighbourhoods.
Lack of community
awareness and interest.
Need for a reliable and
skilled partner with sense
of entrepreneurship.
Complex management.
Model 4
Privately owned -
Privately operated
Profit-seeking enterprise based
on ideal compost market
conditions. Income is
generated through compost
sale and collection fees.
Private sector Introduces recycling and
composting into the SWM policy.
Transparent regulations for public -
private partnerships.
Cooperates in supplying raw
waste and disposal of residues.
Alleviates the municipal burden of SWM
through private sector participation.
Provision of additional funds and know-
how through private investors.
Clear contracts ensure reliable
partnerships with private entrepreneurs.
Can create employment and business
Lack of private land for
composting activities.
Lack of vital compost
markets if compost is not
a well-known product.
Table 4.1: Management models for decentralised composting
Activity 2: Determine the viability of the project:
Benefit-Cost Analysis
The purpose of a benefit-cost analysis is to assess the
financial viability of the composting scheme. This activity is
very important for project planning. If a detailed benefit-cost
analysis is done thoroughly as part of the feasibility study,
appraisal is facilitated and potential financial risks can be
determined. You should be conservative. All projects have
certain risks and using too favourable assumptions can lead
to a failure. If you have no experience with financial issues,
ask for help to facilitate that activity.
The benefit-cost analysis should be undertaken only after a
project is found to be feasible on technical, environmental
and social considerations. The investments made on
projects do not usually yield immediate return, as the return
is generated over a number of years. Similarly, the costs
incurred on the project may be spread over a number of
years. Simply subtracting the costs from the revenues of
each year does not allow a reliable judgement of the
financial viability of the project over several years. There is
the need for converting future costs incurred and revenues
to be received to a common base called “present value”.
The net present value calculation (NPV) and the benefit-
cost ratio (BCR) have proven to be suitable methodologies
for determining the viability of composting schemes. The
calculation of the BCR provides additional quantitative
information on the viability of a project. The following
methodology for NPV is derived and adjusted from Jewell
(An Integrated Approach to Business Studies) and the ADB
Handbook for the Economic Analysis of Water Supply
Projects.
The financial benefit-cost analysis includes the following
steps:
(a) Set a time frame for your project (e.g. 5 -10 years)
(b) Determine annual project revenues
(c) Determine project costs
(d) Calculate annual project net benefits
(e) Determine the appropriate discount rate
(f) Calculate the financial net present value (NPV)
(g) Calculate the benefit-cost ratio (BCR)
To be able to calculate NPV and BCR, consult the results of
the previous tasks and activities and link this information
with actual or assumed costs and revenues. (For instance:
the waste collection fees that residents are willing to pay,
market prices for compost, costs of purchasing technical
equipment, salaries, etc.)
The calculation steps are illustrated by a simplified
example of the benefit-cost analysis for a decentralised
composting plant similar to those established in
Bangladesh. It is assumed that the plant is managed by
a private entrepreneur who uses his privately owned
land and his own financial resources. The plant has the
capacity to process three tons of biodegradable waste
per day collected from 3400 households (approx. 3.5
tons incoming waste). Households pay a monthly
collection fee to the entrepreneur. Additional revenues
are generated through the sale of compost. All
investments are made in the first year before operation
starts. The income and operation cost from year one
are constant over the total project period of 5 years.
(a) Determine a time frame for your project (e.g. 5 -10
years)
In this example the project period is five years, which is
determined by the contract between the municipality and
the private entrepreneur. In other instances the project
period can also be set according to the expected lifetime of
the equipment.
(b) Determine annual project revenues
The revenues are usually determined for each year of
operation and for different revenue types. They are based
on your market analysis and your marketing strategy (Task
1, Activity 3). The forecast of sales revenues is a critical
factor in the calculation because it strongly influences the
final result. Again, you should be conservative when
estimating the sales revenues.
In the case of decentralised composting, usually, there are
two typical revenue types: revenues from the sale of
compost and revenues from waste collection fees. But there
might be other income types such as income from the sale
of recyclables or potted plants or income from carbon
credits in the framework of the Clean Development
Mechanism (CDM).
In this simplified case is assumed that the revenues are
constant over the calculated period. (see Table 4.2) In a
different case, the collection fees might increase over years
or the number of households served might vary. In reality,
the compost prices might also need to be adjusted to
accommodate the market behaviour.
Table 4.2: Annual revenues of a decentralised composting plant
processing 3 tons biodegradable waste per day
Note: 1 US $ = Tk. 50
(c) Determine project costs
It is necessary to differentiate between cost types to
calculate the Net Present Value (NPV) or Benefit-Cost Ratio
(BCR) for a new project. Investment costs usually occur at
the beginning of a project, while annual operation costs go
along with the daily activities. Financial sources for initial
investments can be manifold, e.g. the municipal budget,
development agencies or commercial loans. Depending on
34
Item Tk US $
Sale of compost 750 kg/day @
Tk. 2.5/kg (320 days/year)
600000 12000
Monthly fee for house-to-house
waste collection service from
3400 households @ Tk. 10/
household
408000 8160
Total Revenues/ year 1008000 20160
the financing mechanism additional annual costs for
repayment of loans and interest (capital costs) need to be
considered in the calculation.
Operation costs are often divided into fixed costs (e.g. fixed
monthly rents or repayments of loans) and variable costs
(e.g. irregular maintenance costs, fuel, additives or
electricity) but a detailed explanation of these aspects
cannot be covered by this handbook. Further helpful
literature is listed at the end of this chapter.
In this example the operating cost comprises all costs
including salaries of waste collectors and workers,
electricity and water, costs of additives and technical
maintenance. Table 4.3 (investment costs) and 4.4
(operational costs) show how costs can be determined and
summarised. Capital costs are not considered in this
example.
Note that this calculation does not consider costs for
promotion and marketing of compost. Your might need to
consider additional cost for promotion campaigns, depending
on the marketing strategy you follow. At the start of the project
costs are higher than once a market is established. In any
case, the costs for promotion should not be underestimated
and need to be included in the budget of the annual
operational cost of a composting plant (Table 4.4).
35
Table 4.3: Investment costs of a decentralised composting plant processing 3 tons biodegradable waste per day
Note: US$1 = Tk. 50; 1 katha = 720 sq.ft.
Table 4.4: Annual operational cost of a composting plant processing 3 tons biodegradable waste per day
Note: US$ 1 = Tk. 50
Item Tk US $
Salary of 6 workers @ Tk. 2000/month x 12 months 144000 2880
Salary of 3 van drivers @ Tk. 1500/month x 12 months 54000 1080
Salary of 6 waste collectors @ Tk. 800/month x 12 months 57600 1152
Salary of plant manager @ Tk. 5000/month x 12 months 60000 1200
Maintenance costs for equipment (annual) 10000 200
Electricity and water consumption (annual) 5000 100
Additives for composting process (annual) 12000 240
Total Operational Cost 342600 6852
Item Tk US $
Purchase of land: 5 katha @ Tk. 150000/katha 750000 15000
Construction of roofed sorting platform: 360 sq.ft @ Tk. 120/sq.ft 43200 864
Construction of roofed composting shed with drainage facility: 2142 sq.ft @ Tk. 120/sq.ft 257040 5140
Construction of office, bathroom, toilet and storage for recovered recyclables 120 sq.ft @ Tk.
500/sq.ft
60000 1200
Construction of roofed screening area and packaging area: 95 sq.ft @ Tk. 120/sq.ft (additonal 445
sq.ft are not roofed – no additional costs)
11400 228
Purchase of 3 rickshaw vans @ Tk. 15000/rickshaw van 45000 900
Water & electricity connection 50000 1000
Shovels, buckets, balance, protection gear, overalls for workers etc. 50000 1000
Total Investment Cost 1266640 25332
(d) Calculate annual project net benefits
The annual project net benefit is the difference between
revenues and costs for each year. They are calculated for
each year of the operation period. Table 4.5 shows the
annual net benefits for the decentralised composting plant
in US$. The high costs at year 0 are the total investment
costs of the project. As there are no revenues in that year,
the annual net benefit is negative.
Table 4.5: Calculation of annual net benefits of a decentralised
composting plant (calculation in US$)
(e) Determine the appropriate discount rate
The annual net benefits shown in (d) do not present the real
benefit of the project, as time is not considered. It is
necessary to adjust the revenues and costs, which occur in
the future. The method used for converting future cash flows
(costs and revenues) to present value is known as
discounting. Discounting future costs and revenues
enables us to give them an appropriate weight in our
present decision (see Box). Usually, the discount rate is
determined according to the local interest rates for loans.
The discount rate chosen should be close to the rate
prevailing in the market to reflect the scarcity of resources.
Why discounting?
Suppose your friend offers you a US$ 100 gift today or
after one year. You certainly would choose to get the gift
right away. There are different reasons for that: You may
feel the risk that your friend may change his mind over the
year, or you want to use the money now for buying some
books or CDs you recently saw in a shop. You may even
want to put the money to a bank account to gain interest
for a later purchase. In all cases you have more benefits
from the gift if you get it today rather than after one year.
These examples show us that the value of money
decreases with time. The longer you have to wait the
lower is the present value for you.
The calculation of the present value (PV) is given by the
formula:
where
A is the annual revenue/cost
r is the discount rate (local interest rate)
n the year when the revenue/ cost occurs
The calculation of present values for a whole project is quite
daunting. Therefore, practitioners developed discount factor
tables, which can easily be used in the day-to-day work. The
factor is calculated by setting A = 1 currency unit, thus, the
discount factors are applicable for all values of all
currencies. Table 4.6 shows a selection of discount factors
of different discount rates for periods up to seven years. As
described above, the selection of the discount rate depends
on the interest rates of the local market.
36
Year Annual
revenues
Annual cost Annual net
benefit
0 0 25332 - 25332
1 20160 6852 13308
2 20160 6852 13308
3 20160 6852 13308
4 20160 6852 13308
5 20160 6852 13308
(f) Calculate the financial net present value (NPV)
Based on this information it is possible to calculate the net
present value (NPV). The NPV is the sum of the
discounted revenues minus the discounted costs. If the
sum of discounted revenues exceeds the investments, than,
the NPV is positive and the project is viable. Table 4.7
shows the calculation for the described example that we
have been considering.
Table 4.7: Net present value calculation for a decentralised
composting plant (calculation in US$)
A positive NPV indicates a profitable project, meaning that
the project generates sufficient funds to cover all costs and
expected repayments under the assumed conditions. It can
run independently and is expected to generate profits. The
higher the NPV the more the profit that can be generated. A
negative NPV indicates that a project is not financially viable
under the assumed conditions. Such projects must seek for
additional income (e.g. subsidies) or for cost reductions to
become financially viable. Of course, the outcome of the
NPV calculation strongly depends on the chosen discount
rate. If the discount rate is high, the revenues must be
higher to achieve a positive NPV.
(g) Calculate the benefit-cost ratio (BCR)
Finally, calculate the benefit-cost ratio. Similarly to the NPV,
determine the discounted revenues and costs for each year
and add them up. Divide the sum of discounted revenues
(a) by the sum of discounted cost (b) to determine the BCR.
If the BCR is greater than one, the project is viable. The
BCR partly quantifies the viability of the project. In the
example shown in Table 4.8 the BCR is 1.38. That means
investing 1 US$ today, you will get 1.38 US$ in return after
five years.
Table 4.8: Benefit-cost ratio calculation for a decentralised
composting plant (calculation in US$)
In any case it is advisable to repeat the calculation with
changing variables in order to assess possible sensitivities
of your calculation. For instance:
vary the number of households who pay for the service or
assume increasing salary costs over time or
assume you have to take a loan and need to pay interest.
37
Table 4.6: Discount factors for selected discount rates
Year 6% 8% 10% 12% 14% 16% 18% 20%
1 0.9434 0.9259 0.9091 0.8929 0.8722 0.8621 0.8475 0.8333
2 0.89 0.8573 0.8264 0.7972 0.7695 0.7432 0.7182 0.6944
3 0.8396 0.7938 0.7513 0.7118 0.6750 0.6407 0.6086 0.5787
4 0.7921 0.7350 0.6830 0.6355 0.5921 0.5523 0.5158 0.4823
5 0.7473 0.6806 0.6209 0.5674 0.5194 0.4761 0.4371 0.4019
6 0.7050 0.6302 0.5645 0.5066 0.4556 0.4104 0.3704 0.3349
7 0.6651 0.5835 0.5132 0.4523 0.3996 0.3558 0.3139 0.2791
Year Annual
revenues
Annual
cost
Annual
net
benefit
Discount
factor
(discount
rate 16%)
NPV
0 0 25332 - 25332 1 - 25332
1 20160 6852 13308 0.8621 11473
2 20160 6852 13308 0.7432 9890
3 20160 6852 13308 0.6407 8526
4 20160 6852 13308 0.5523 7350
5 20160 6852 13308 0.4761 6336
Sum of NPV 18243
Year Annual
revenues
Annual
cost
Discount
factor
(discount
rate 16%)
Annual
discounted
revenues
Annual
discounted
costs
BCR
= (a/b)
0 0 25 332 1 0 25332
1 20160 6852 0.8621 17380 5907
2 20160 6852 0.7432 14983 5092
3 20160 6852 0.6407 12917 4390
4 20160 6852 0.5523 11134 3784
5 20160 6852 0.4761 9598 3262
(a) 66012 (b) 47767 1.38
Activity 3: Develop the contract for involved
partners
Once you have selected the appropriate business model
and have completed the benefit-cost analysis, you may get
the approval to set up the decentralised composting
scheme. It is crucial that the partnership is defined in the
form of a memorandum of understanding or contract. In
some countries, it is not common to sign contracts.
Nevertheless, as long as private investments are involved,
a contract provides a certain level of security. Furthermore,
a contract clarifies the rights and duties of the relevant
partners and helps to avoid future quarrels. The set up of
contracts needs know-how and extensive negotiations
among stakeholders. The sample contract shown in Annex
5 is derived from a case in Bangladesh and further
generalised. It can act as guidance but does not claim
completeness or applicability in all cases.
Further reading
Coad, Adrian (2005): Private Sector Involvement in Solid
Waste Management – Avoiding Problems and Building
Successes. Published by CWG – Collaborative Working
Group on Solid Waste Management in Low- and Middle-
income Countries (order: booklet with CD: www.skat.ch or
full version: www.gtz.de)
Asian Development Bank (1999): Handbook for the
Economic Analysis of Water Supply Projects, Economics
and Development Resource Centre. Though the focus is on
water supply, many aspects are also relevant for SWM.
(download from: http://www.adb.org/publications/year.asp -
ADB Publications Catalogue)
Jewell, Bruce, R. (2004): An Integrated Approach to
Business Studies. 4th Edition. Pearson Education Limited,
Harlow, UK.
GTZ (2005): Improvement of Sanitation and Solid Waste
Management in Urban Poor Settlements, GTZ, Eschborn,
Germany (order or download from http://www.gtz.de/en
themen/umwelt-infrastruktur/abfall/2841.htm
38
Task 5
Development and Design of Collection System
Identifying Stakeholder Interests : Task 1
Assessing Target Community Interests and Land Availability : Task 2
Data Collection : Task 3
Preparing a Business Plan and Financial Projections : Task 4
Development and Design of Collection System : Task 5
Design and Construction of Composting Facility : Task 6
Operating and Maintaining a Composting Facility : Task 7
Marketing of Compost : Task 8
After choosing the organisational setup of the composting
scheme and partners, you can focus on technical aspects of
the scheme. Guidance of this handbook now shifts from
planning to implementation.
As mentioned several times in previous chapters, the
success of a composting scheme is closely linked to
successful waste collection. Customers (households) must
be satisfied with the service provided. Waste should be
collected daily or at least every alternate day to prevent
odour emissions and facilitate waste separation.
Task 5 focuses on the waste collection system and then
Task 6 reviews the composting system. You can skip Task 5
if you are in the comfortable position of already running a
well-organised waste collection service or receiving the
waste from a primary collection service for which you are
not responsible.
After finalising the activities of Task 5, you will be informed
about:
the most appropriate vehicles and the number required
how to ensure the participation and support of the
community served
how to promote waste segregation at source (in the
household)
Activity 1: Select the most appropriate vehicles
Selection of the most appropriate waste collection vehicles for
a specific collection area is an important task. Well-designed
waste collection vehicles contribute to increasing waste
collection efficiency and collectors’ safety. As mentioned in
Task 2, several factors, such as topography, settlement
structure or road conditions, have to be considered. Vehicles
already used for transport of goods on the local market offer
an indication of the types of vehicles which could be used for
your collection scheme. Remember that your scheme will be
responsible for primary waste collection. Activity 1 assumes
that the composting plant will be located in or close to the
area where the waste collection will take place. Thus the
collection vehicles will generally be small and suited to the
transport of waste for shorter distances.
During selection, the following aspects should be taken into
consideration:
Road conditions and settlement structure: The vehicles
may have to travel through narrow lanes.
Type of household waste collected: If the sand content is
high, the container should be constructed with a strong
grid instead of a closed metal sheet to allow the sand to
fall out.
Since waste can be corrosive and abrasive, ensure
protective measures for metal surfaces (e.g. paint)
particularly for containers.
The volume of the vehicle is limited by waste density and
travel distance. The denser the waste, the heavier it
becomes! A person cannot push or pull the same load as
a motorised vehicle, e.g. 2 m
3
waste of 0.5 t/m
3
density
weigh 1 ton! This is already above the limit that a person
can push or pull on most surfaces.
The service area determines the volume and number of
trips the vehicle has to cover.
Select good quality vehicles even though they are more
expensive. You will save money in the long run, as these
vehicles need fewer repairs.
Check the availability of spare vehicle parts on the local
market. Place special attention to the wheels and
bearings, as they are the most important part of the
vehicle.
Determine whether women or men are responsible for
waste collection. Some vehicles may be unsuitable for
women others for men.
The storage containers of the vehicles should be covered
to avoid the waste from falling out and protect it from
excessive rainfall.
If you promote source segregation, plan different
compartments on your collection vehicle.
Photograph 5.1: The manual handcart with a grid container and broad
wheels was adapted to the local sandy road conditions and high sand
fraction. The sand falls through the grid, thus reducing the weight of
waste (AGRESU – GTZ GmbH, Maputo, Mozambique)
41
Task 5: Development and Design of Collection System
Technology is dominated by two types of people: those who understand what they do not manage, and those who
manage what they do not understand. (Putt’s Law)
42
Table 5.1 is compiled from various sources. It summarises different vehicle types and their characteristics.
Table 5.1: Comparative characteristics of waste collection vehicles
Source : Ogwa,1988
Parameter Manual
Handcart
Animal Cart Rickshaw
Van
Tractor
Trailer
Fixed Bed
Truck
Tipper Truck Compactor
Truck
Container
Truck
Range < 2 km < 5 km < 10 km < 15 km Unlimited Unlimited Unlimited Unlimited
Speed Very slow Relatively slow Slow Moderate Fast Fast Fast Fast
Road size
suitability
Narrow Moderate Narrow Moderate Wide Wide Wide Wide
Volume per
vehicle
0.5 m
3
2 m
3
2-3 m
3
4 m
3
8 m
3
10 m
3
12 m
3
20 m
3
Labour
requirements
1 Collector 1 Driver
2 Labourers
1 Driver
1 Labourer
1 Driver
2 Labourers
1 Driver
3 Labourers
1 Driver
2 Labourers
1 Driver
2 Labourers
1 Driver
Investment
costs
Very low Low Low Relatively low Moderately
high
High Very high Very high
Maintenance
costs
Very low Low Low Relatively low Moderately
high
High Very high Very high
Service life 5 years 5 years 10 years 10 years 5 years 5 years 5 years 5 years
Trips/day 2 2 3 2 2 4 3 3
Photograph 5.2: Rickshaw with front loader and containers in which
waste is separated into three fractions (CEE Kalyan Nagar Residence
Association, Bangalore, India)
Photograph 5.3: Rickshaw with a covered collection container and back
doors (Waste Concern, Waste Collection and Composting Scheme,
Mirpur, Dhaka, Bangladesh)
Photograph 5.4: Horse cart capable of pulling up to eight rectangular
containers (container exchange system) (Community Organisation,
Agaki, Ethiopia)
Photograph 5.5: Moto-rickshaw for long-distance waste collection. The
tailboard is often higher to prevent the waste from falling out (CEE
Kalyan Nagar Residence Association, Bangalore, India)
43
Activity 2: Select the appropriate waste collection
system
The outcome of the community survey should already
reveal the collection system favoured and affordable by the
community. Different collection models are possible:
House-to-house collection
There are two basic types. In back-door or yard collection
the waste collector enters the garden or courtyard and
carries the waste bin to the collection vehicle. After
emptying, the collectors return the bin to its original
location. This method is not culturally acceptable in many
places. In front door collection the collector rings the bell
or sounds a signal outside and waste is brought out to
him by a member of the household. This collection model
is very effective and suitable for source segregation, but
is also most labour-intensive and time-consuming.
Furthermore, it requires at least one household member
to be present during collection.
Block collection/Bell collection
A vehicle follows a predetermined route at fixed intervals;
it stops at selected locations where a bell is rung.
Households bring out and hand over their waste
containers to the collection crew.
Kerbside collection
This type of collection system requires regular service
and a fairly exact collection schedule. The households
have to be instructed to put their (ideally closed) waste
bin in front of their house just before the regular collection
schedule. This will prevent rummaging by waste pickers
or animals.
Communal collection bins
This widely used system requires the households to bring
their waste to a communal bin, which is emptied into
large trucks. This system is inappropriate for composting
as waste may be stored for over several days in the
households before being brought to the container and so
the waste becomes partly decomposed and compressed.
Table 5.2 is drawn from a UNCHS publication. It summarises
and compares the different waste collection models.
No matter which collection system you choose, inform the
households about its organisation and how they can
contribute to its smooth and efficient operation. A regular and
reliable waste collection service motivates many households
to cooperate. Here the Community Committee (see Task 2)
is an important communication partner. Motivation will
generally lead to greater improvements than strict
regulations or even threats of punishment, whose
enforcement is beyond your competence. Hence, you rely
on voluntary cooperation
.
Photograph 5.6: House-to-house collection requires the presence of a
household member (Waste Concern, Dhaka, Bangladesh)
Description House-to-
House
Collection
Kerbside
Collection
Block
Collection
Communal
Collection
Householder
cooperation in
carrying refuse
bins
No Yes Yes Yes
Householder
cooperation in
emptying refuse
bins
No No Optional Yes
Need for
scheduled
service
Optional Yes Optional No
Susceptibility to
scavenging
None High None Very high
Average crew
size
3-5 1-3 1-3 1-2
(portable)
2-4
(stationary)
Trespassing
complaints
Yes No No No
Level of service Good Good Fair Poor
Collection costs Very high High Medium Low
Table 5.2: Comparison of various solid waste collection models
Source: UNCHS (Habitat), Refuse collection vehicles for developing
countries, p. 10, 1988
Activity 3: Calculate the number of vehicles
required
How many vehicles are required to collect the waste in your
service area? To be able to answer this question, some
assumptions and calculations are necessary:
Firstly, determine the volume your vehicle can carry. The
aforementioned table provides guidance on this subject.
Secondly, decide on collection frequency and model
(daily, every alternate day, house-to-house, kerbside,
block collection, street bin collection) as they influence
the time required.
Thirdly, assess time required for one collection team to fill
the selected vehicle given a certain household density.
This indicates the number of trips of one team per day.
Add time required to travel from the composting plant to
the collection area and back. A map of the community
could be very useful here. Photograph 5.7 illustrates how
a community organisation in Bangalore has structured
the service area.
Finally, calculate the number of collection teams
necessary to cover the entire area. The calculation is
based on the time required for each collection trip and the
daily working hours of each collection team.
Table 5.3 will help to structure and calculate your data. It
exemplifies the planning of a house-to-house waste
collection system in a rather flat area. The following
assumptions are the bases for the calculation:
Table 5.3: Example of the calculation of the vehicle demand
Experience also reveals that such a calculation provides
only preliminary indication of the number of collection
vehicles required. This calculation will certainly have to be
adapted after the first operational experience. Be prepared
to reorganise collection or to add an additional collection
crew to the team.
Investment in an additional reserve vehicle in the event of a
breakdown is highly recommended. Such breakdowns are
very likely, especially if maintenance of the collection
vehicles is neglected. Ensure frequent checks and
maintenance of all moving parts. Check the condition of:
bearings (greasing necessary?)
wheels and handles (air pressure, fixed?)
brakes (functional?)
container (cleaning new point, necessary?)
engine (if any)
Photograph 5.7: Solid waste collection zones and routes in a municipal
district of Bangalore (CEE, Bangalore, India)
Activity 4: Community participation and mobilisation
for waste collection
Since details on community participation and mobilisation
could fill yet another book, this handbook provides merely
some suggestions on how to mobilise the community.
Further reading on community mobilisation is listed at the
end of this section.
Community mobilisation for a waste collection and
composting scheme generally aims at:
raising the awareness of people regarding the benefits of
a cleaner neighbourhood and compost production
explaining how waste can be turned into a resource
explaining how the scheme is organised and what each
individual is expected to do
encouraging people to come forward with ideas and
initiatives, and to make complaints
enhancing willingness of the households to pay for the
new service
44
Parameters
Collection frequency & model daily, house-to-house
Average waste generation 0.6 kg/cap = 3 kg/household
Waste density 350 kg/m
3
Volume of vehicle 1 m
3
Collection time per vehicle 3 hours
Time to and from composting area
15 + 15 minutes
Coverage 100 households
Labour requirement (1 team) 2 persons
Result:
One team can cover two trips per day (8 hours).
This is equal to a total of 200 households per day.
Total number of households
in the project area
700
Result:
Three teams can cover
600 households
too little
Four teams can cover
800 households
too much
Final decision:
Start with four teams to allow a reserve capacity and a
certain operational flexibility.
The results of the community survey in Task 2 provide an
important basis for community mobilisation.
Contact the community leaders and the Community
Committee and inform them about the latest decisions
and future objectives. Present the results of your survey
and explain why a specific collection system will be
applied.
Contact households directly or during a community
meeting using short and simple information leaflets.
Inform them about the launching of the collection system,
i.e., days and times they should expect the waste
collectors. Distribute practical collection schedules for the
households to display close to their waste bins.
If the scheme creates new jobs, try to recruit the staff
from among the community members, even if you have to
provide additional on-the-job training. The more local
people are involved, the more the new service will be
accepted.
Community mobilisation is a never-ending job, as interest
and participation have to be maintained through regular
information. Beneficiaries tend to take the service for
granted once it is established and smoothly running.
Remind them of the efforts and work required to keep up the
service and operation (e.g. inform the community at least
once a year of the latest developments of the collection and
composting scheme). School visits and open days may help
to raise the local profile of the scheme.
Activity 5: Organise and introduce fee collection
Studies have revealed that fee collection can be a tedious
and time-consuming task. Inefficient fee collection, which
can harm the viability of the collection and composting
scheme, is mainly caused by the low level of acceptance of
the scheme by the households. This clearly indicates the
importance of a preliminary study and involvement of the
community in the planning process. If the majority of the
households are willing to pay, other households will follow.
There will always be households stating that they are
already charged for such a service and, therefore, refuse to
pay additional fees. Others claim that they do not trust the
fee collectors or do not have the amount ready. However, the
collection rate can be increased by three simple measures:
1. Introduce periodic fee collection (e.g. monthly).
Although it is more expensive to collect each month,
the regularity of the collection and the smaller amount
to be paid (compared to a bi-annual collection) should
produce a better response.
2. Officially appoint fee collectors.
Inform households about the responsible fee collector,
who could be the waste collectors, an employee of the
scheme or a voluntary community member, depending
on the social network. However, according to
experience, waste collectors are quite capable of
collecting the fees efficiently, as they visit the
households regularly and are known to the inhabitants.
3. Ensure accountability and transparency.
People want to know what happens with their money.
Provide annual information on use of the money
through information campaigns. As accountability is so
important, introduce a receipt system. When receiving
the monthly waste fee, collectors hand out numbered
receipts, thereby providing residents with proof of their
contribution. The fee collector has to report to the plant
manager or to the accountant by handing over the fees
and duplicates of the receipts.
Activity 6: Try to promote source segregation
The most labour-intensive and tedious task of the
composting process is waste separation. It can be facilitated
if households of the community agree to segregate the
waste, putting biodegradable (or “wet”) waste into a different
container from the one used for other wastes (see Task 7).
Recyclables are more easily sorted and of higher quality
since they are less polluted. However, implementation of
source segregation requires long-term preparation and
vehicle modification (two compartments in the container).
If at-source segregation is being considered, this will require
an intensive and long-lasting publicity and follow-up
campaign in order to achieve a satisfactory degree of
segregation, unless there are significant financial
incentives. The European experience shows that in many
cities source segregation could only be implemented by
accompanying measures such as an incentive tax
according to the “polluter-pays-principle”. That means that
households pay fees only for residual waste collection;
organic waste and recyclables are collected at no cost to
the domestic generator. In this way more effective
segregation results in lower fees. Such accompanying
measures require an overall enforcement of existing solid
waste management laws and regulations, and greatly
depend on the political environment and the level of
environmental awareness among the general public.
Hence, do not expect too much success at the beginning,
as the scheme is dependent on the awareness of the
households and their voluntary participation. The following
three activities will raise the awareness of the community:
Prepare and distribute leaflets among the households
describing the benefits of source segregation and
guidelines helping residents to differentiate between
inorganic and organic waste.
Affix posters with basic information to your collection
trucks.
Organise an open-house event, inviting the community to
the composting plant. Explain on site why source
segregation greatly contributes to enhancing the
operation of the composting plant. However, make sure
that your composting plant is in excellent condition when
you invite the community!
45
Further reading
UNCHS (Habitat) (1988): Refuse Collection Vehicles for
Developing Countries, Nairobi (out of print but available on
request from www.sandec.ch)
Rouse, J.R. & Ali, S.M. (2002): Vehicles for People or
People for Vehicles, Loughborough University, ISBN: 1
84380 012 8, Loughborough (download from:
http://wedc.lboro.ac.uk/publications/catalogue.htm)
UNDP & Ministry of Urban Development, Government of
India (1993): Community based solid waste management –
Project Preparation
Pfammatter & Schertenleib (1996): Non-Governmental
Refuse Collection in Low-Income Urban Areas, EAWAG/
SANDEC, Duebendorf, Switzerland (download from:
www. sandec.ch)
GTZ (2005): Improvement of Sanitation and Solid Waste
Management in Urban Poor Settlements, GTZ, Eschborn,
Germany
Ogawa. H. (1988): “Selection of Appropriate Technologies
for SWM in Asian Metropolises’ a paper published in
Regional Development Dialogue, Volume 10, No. 3,
UNCRD, Nagoya, Japan.
46
Task 6
Design and Construction of Composting Facility
Identifying Stakeholder Interests : Task 1
Assessing Target Community Interests and Land Availability : Task 2
Data Collection : Task 3
Preparing a Business Plan and Financial Projections : Task 4
Development and Design of Collection System : Task 5
Design and Construction of Composting Facility : Task 6
Operating and Maintaining a Composting Facility : Task 7
Marketing of Compost : Task 8
This section describes a composting plant and its various
components. Since local conditions strongly influence final
composting plant design, the descriptions and illustrations
provided should be used merely as guidelines and
recommendations. Local construction experts should be
consulted and the usage of materials adapted to the local
context, but always related to the key functions of each
component.
Task 6 gives guidance on design and construction of a
composting facility processing three to five tons of (mixed)
household waste per day. You will learn:
how much space is required by a composting facility
treating three tons of waste per day
fundamental construction rules for the two composting
processes presented
useful construction material and equipment
how to divide the available space into functional
compartments to enhance the workflow.
Task 6 describes the design of composting plants applying
the following two techniques:
Windrow Composting
Box Composting
The choice of a composting technology is dependent on
several criteria, such as space availability near the housing
area served. Box composting units require limited space
and can be placed even along roadsides (see Photograph
1.2), whereas windrow composting schemes need sufficient
area for a proper setup. In any case they should be
protected from unauthorised access and public view. Table
6.1 provides an overview of possible criteria to facilitate
selection of the most appropriate technology.
Activity 1: Plan and decide on the composting
plant layout
A composting plant comprises an operation area and a
“green” buffer zone. The buffer zone, formed by a belt of
bushes and trees surrounding the operation area, improves
the visual appearance of the composting plant (see
photograph 6.6). The operation area is divided into different
zones. It contains space for waste unloading and sorting,
composting, maturing, sieving and bagging of the compost,
including storage space for compost and recyclables. These
zones must be arranged so as to ensure efficient workflow
of the composting process.
Annex 4 contains two layouts of typical composting plants
similar to the ones operated in Bangladesh. Annex 4A
provides an example of a windrow composting plant, and
Annex 4B a composting plant applying the box technique.
Table 6.2 indicates the minimum space requirements for the
different workflow units within the premises of a composting
plant. Additional space should be allocated for a caretaker’s
office and sanitary facilities for the workers. Take into
account that the final setup of the site is strongly dependent
on the local conditions.
49
Task 6: Design and Construction of Composting Facility
For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.
(Richard Feynman)
Table 6.1: Matrix for selection of the most appropriate technology
Constraining Criteria Windrow
Composting
Box
Composting
Explanation
Space is limited X
Box composting requires less space than
windrows.
Long-term availability of land is not ensured X
Windrow composting requires less investment in
stationary infrastructure.
Financial constraints for initial investments X
Windrow composting is less expensive due to
lower infrastructural requirements.
Labour is hard to find X
Box composting requires less manpower than
windrow composting.
Working with waste is perceived as “dirty work” X
Box composting is less labour-intensive than
windrow composting.
Table 6.2: Required space for a composting plant processing three
tons of waste per day
These composting schemes can be scaled up or down
depending on the local conditions. Since both composting
systems are modular, the composting area can be extended
to five tons of waste per day. To protect the workers from
difficult and unhygienic working conditions, this capacity
should not be increased beyond that amount as the system
is still based on manual work. If more waste has to be
treated, a higher degree of mechanisation (causing higher
investment and operational costs) will have to be
considered. However, higher capacities are unnecessary,
as the decentralised composting sites seldom cover more
than 3000 households.
Activity 2: Plan the required key features
The following key features have to be considered during
planning and construction regardless of the type of
composting scheme chosen:
On-site water supply is a basic infrastructural requirement
on a composting site. Since it is used for hygienic purposes
and for watering the compost heaps, a reliable water supply
should be ensured, such as a standpipe on the site. An
additional water storage tank is, however, advisable if the
water supply is not continuous. A further useful feature is a
rainwater harvesting system. The roof of the composting
shed and other facilities can be specially designed to collect
rainwater from the rooftops. During the rainy season, water
can be collected in a tank to bridge water shortages during
the dry season. The storage volume is dependent on the
length of the dry season and on the daily water demand.
Rainwater can be used for the composting process, for
cleaning and washing of the composting plant and for
watering of the green belt. Figure 6.1 shows a rainwater
collection and storage system at a composting site. A guide
for capacity calculation and design is available on Sandec’s
webpage: Rainwater Harvesting at the Co-Composting Site
in Kumasi, Ghana.
http://www.sandec.ch/Publications/PublicationsHome.htm#SWM
Figure 6.1: Diagram of a water storage system combining water storage
and rainwater harvesting
Photograph 6.1: Rainwater harvesting system at the co-composting
pilot plant in Kumasi, Ghana. The small “first flush tank”, behind the
main tank, collects the first incoming rainwater, diverting dust and dirt
from the roof. (Sandec)
Both windrow and box composting operations should
be conducted under a roof to protect the compost piles
from excessive rain and sun. Simple light structures with
vertical steel angles, mild steel pipes or wood or bamboo
poles can be used to support the roof. Photograph 6.1 and
Figure 6.5 illustrate two types of roof constructions. To allow
easier workflow during composting, the minimum distance
between the pillars should be three meters. Corrugated iron
sheets, bamboo thatch or any other locally available roofing
50
Type Required Area
Windrow
Composting
Required Area
Box
Composting
Roof
Composting area
Sorting area 40 m
2
40 m
2
yes
Storage of rejects 30 m
2
30 m
2
yes
Storage of
recyclables
10 m
2
10 m
2
yes
Composting pad 400 m
2
360 m
2
yes
Maturation area 150 m
2
150 m
2
yes
Screening and
bagging area
35 m
2
35 m
2
yes
Compost storage
area
25 m
2
25 m
2
yes
Sub-total
composting area
690 m
2
650 m
2
Facilities
Office 16 m
2
16 m
2
yes
Sanitary facilities 10 m
2
10 m
2
yes
Tool shed 10 m
2
10 m
2
yes
Water supply point 4 m
2
4 m
2
no
Additional space
requirements
Vehicles parking area 30 m
2
30 m
2
no
Green buffer zone
(trees/bushes)
50 m
2
50 m
2
no
Total area 810 m
2
770 m
2
material can be used. Depending on the soil bearing
capacity, special attention should be given to construction of
the foundation to avoid settlement and cracks in the
structures. Jute or specially designed compost fleece is
suitable in semi-arid and arid regions to protect the compost
from excessive evaporation. Since compost requires
oxygen for decomposition, the cover must be permeable to
air. Photograph 6.2 illustrates the use of a compost fleece
on small windrows.
Photograph 6.2: A composting fleece protects compost piles from
excessive sun and rain if no roof is available. The fleece also prevents
the compost from being rummaged by animals. (Sandec, Community
Composting, Switzerland)
The sorting area consists of a sealed concrete surface
where waste is sorted into organics, inorganic recyclables
and rejects. The sealed surface facilitates cleaning after
sorting is completed. Since the waste delivered may be high
in moisture, the area should be slightly sloped (1%) to avoid
leachate ponding. A drainage system collects leachate and
cleaning water to be reused for watering composting
windrows (see Annex 4C).
In Bangladesh, sorting is conducted on the floor with rakes
and shovels (see Photograph 7.1 in Task 7). In other
contexts, construction of a sorting table or platform allowing
people to stand upright could be appropriate. Three sorting
options are illustrated in Figures 6.2 to 6.4. More
sophisticated sorting systems with conveyor belts are not
recommended for such small-scale composting facilities, as
they require significantly higher investment and operational
costs.
Figure 6.2: Sorting on the ground. Organic waste is filled into buckets
and carried to the windrow or box
Figure 6.3: Sorting on a platform. Waste is delivered onto the platform.
Workers stand upright and sort out organic waste and fill it into
wheelbarrows below. Advantage: no further need for shoveling and no
direct contact with the waste
Figure 6.4: Sorting on a sorting table with hinged table top. Waste is
shoveled onto a table and rejects are sorted out. Remaining organic
waste is filled into a wheelbarrow by lifting the table top. This system is
suitable for waste with a very high biodegradable fraction such as waste
from fruit and vegetable markets
The storage areas for rejects and recyclables should be
roofed and possibly enclosed to prevent roaming animals
from entering the site. The area has to be accessible to
trucks, as the rejects have to be collected frequently. A
covered container for rejects, easily picked up and replaced
by a truck, is a good alternative to a storage room. The
necessary storage volume is determined by the collection
frequency. The required amount of storage space can be
calculated by the following equation:
waste
tot
total waste amount (kg)
waste
recyclable
recyclables (kg)
waste
organic
organic waste (kg)
density
rejects
density of rejects (kg/m
3
) varies between
300 and 600 kg/m
3
The area required for the storage zone for recyclables is
dependent on the inherent properties of the materials.
Paper and cardboard for instance only have to be bundled
and piled, while plastic and glass are collected in old bags.
Each plant should have a lockable office equipped with
basic furniture to allow the supervisor to keep the
monitoring and accounting records. It also provides a
sheltered area for breaks and for storing personal
belongings. Sanitary installations, such as toilets and
washing facilities, are essential. After handling waste and
compost, the workers should wash and change their clothes
before leaving the workplace. Small equipment, such as
sieves, shovels and rakes, should be stored in the tool
shed. Such facilities require approximately 40 m
2
, and all
should be roofed and fitted with lockable doors for security
reasons.
51
Specific features of the windrow composting area
The composting area is preferably a concrete slab slightly
sloped (1%) towards one side to allow excessive water from
the compost heaps to flow into a drain. Along the lower end
of the slab, a drainage channel for leachate collection leads
to a collection point. An area of 360m
2
is sufficient to hold
seven parallel windrows (see Annex 4A and 4B).
Triangular aerators significantly enhance windrow
composting. If possible they should be constructed of a
material that is resistant to natural degradation. Aerators
made of bamboo and plastic are described here. The
advantage of the bamboo aerator is its low price and
availability. However, bamboo is not entirely resistant to
degradation and has to be replaced frequently. To construct
bamboo aerators like shown in photograph 6.3, bamboo
strips are nailed lengthwise onto triangular wooden frames
(maintaining equal gaps). The plastic model is made of
perforated plastic panels. This model is more expensive but
also more resistant to natural degradation and has a longer
service life. The sides of a triangular aerator measure 0.6 m
and the entire length of an aerator is 2.7 m. As can be seen
in the schematic layout of Annex 4A about 36 aerators are
necessary for a windrow composting plant that processes
about three tons of sorted organic waste waste.
Photograph 6.4: Piled waste around short plastic aerators (Waste
Concern, Bangladesh)
Specific features of the box composting area
The layout of a box composting system is illustrated in
photograph 6.5, Figure 6.6 and Annex 4B. Box composting
requires less space but more construction efforts and higher
investments than windrow composting. A plant processing
three tons of organic waste requires about 24 boxes (1.45 m
wide, 6 m long and 1.2 m high). The front side of the box is
closed by means of removable wood panels, which can be
removed for emptying the box (see Figure 6.6). Since the
distance between the boxes is 0.75 m, the total space
requirements are lower than for the windrow technology. The
slab on which the boxes are built should be sealed and slope
towards one side. Leachate collection channels leading to
the edge of the composting floor are located between the
boxes and discharge into a central collection point. To
improve the oxygen supply to the pile, the box wall contains
gaps between the bricks. The perforated base of the box
should be resistant to corrosion and thus is equipped with
small PVC pipes or a coated metal grid. This base ensures
better aeration and drainage of excessive water from the pile
(see details in Annex 4C). Finally, perforated PVC pipes (see
details in Annex 4C) are placed vertically inside the box to
provide additional oxygen exchange within the compost
material.
52
Figure 6.5: Cross section of a typical three-ton composting plant (box composting) with details of roof, floor, compost box, and drainage system (Waste
Concern, Bangladesh)
Photograph 6.3: Bamboo aerator; side length of triangular frame 0.6 m,
length 2.7 m (Waste Concern, Bangladesh)
Useful additional composting plant features
Apart from compost production, the composting plant can
promote among the citizens the idea of resource
conservation and recycling. A series of additional
composting plant features are presented here to illustrate
how a composting plant can raise environmental
awareness:
Kiosk: A small, square-shaped structure with a light roof
can be set up within the premises of a composting plant.
The kiosk can be used as a sales and display point for
compost products or potted plants raised on compost. A
kiosk like that shown in Figure 6.7 can help promoting
organic farming and agricultural use of compost to visitors
of the site.
Organic farming demonstration site: If sufficient land and
staff are available, a small plot inside the composting plant
can be used as demonstration unit for organic farming or as
a nursery for pot plants. The core idea is to encourage the
owner of the composting plant to maintain, as far as
possible, the facility clean and green. A clean and pleasant
environment near a composting plant can change negative
perceptions of waste treatment and the use of compost can
be directly demonstrated to visitors. Furthermore, a nursery
creates an additional source of income (Figure 6.8).
Wastewater reuse system: A significant amount of
wastewater is generated during composting and the
cleaning of the facility. Instead of discharging the
wastewater into drains, it can be reused for new compost
piles to maintain the moisture balance and enhance the
decomposition process. Wastewater from the drainage
system can be collected in a small covered storage tank
below ground level. By mixing this wastewater with fresh
53
Photograph 6.5 and Figure 6.6: Box composting plant and close-up model of a compost box with plastic door at the front end facilitating emptying
(Waste Concern, Bangladesh)
Figure 6.8: Composting plant with an integrated plot for organic farming
for promotion. (Waste Concern, Bangladesh)
Photograph 6.6: Nursery and organic farming unit in a composting plant
in Dhaka, Bangladesh (Waste Concern, Bangladesh)
Figure 6.7: Example of a kiosk replicated in 14 towns in Bangladesh
(Waste Concern, Bangladesh)
water from the pipes or rainwater tank, scarce water
resources can be extended and conservation promoted.
Energy efficient lighting system: If the compost plant is
connected to the electricity grid, an energy-efficient lighting
system should be fitted to set a good example of energy
conservation and to reduce operational costs in the long
run.
Activity 3: Plan staffing requirements
Generally, the staff of the composting plant needs to be
willing to work with waste. Such a commitment ensures long-
term capacity building and increases know-how within the
plant. Selection of staff strongly depends on local habits and
values (culture, religion, gender, perceptions) and has to be
discussed in detail (e.g. if women can be involved in waste
handling). Experience reveals that composting plants often
provide interesting job opportunities for underprivileged and
poor people. Formalised waste collection, sorting and
composting ensures long-term employment and the
opportunity to get trained on the job and specialised in
composting. However, some of the workers should be
literate, as the composting process requires reliable
monitoring and recording activities (e.g. temperature, weight
and moisture measurements). Furthermore, the composting
business also offers jobs for dedicated engineers, which
have the overall responsibility of management and
operation. Table 6.3 describes jobs, necessary skills and the
average number of required staff for a composting plant
processing three tons of waste per day.
Activity 4: Plan additional equipment and
expendables
Additional equipment and expendables, as shown in Table
6.4 guarantee workers’ safety and promote efficient process
performance. Most of the equipment is also illustrated in the
photographs in Task 7 (Operation and Maintenance). Apart
from the sieving equipment, most of the expendables must
be replaced frequently (e.g. monthly or annually) and
considered in project budgeting. The waste collection
equipment is not considered here.
Table 6.4: Additional equipment and expendables
Further Reading
Diaz, L. et al. (1993): Composting and recycling municipal
solid waste, ISBN 0-87371-563-2. This comprehensive
book covers all aspects of solid waste collection,
characterisation and recycling. Chapters 6, 7 and 8 focus on
composting and markets for compost.
Haug, R.T. (1980): Compost Engineering, Principles and
Practices, ISBN 0-250-40347-1. This book is more suitable
for technicians and engineers which seek more information
about the process engineering of composting.
Chiumetti A., Chiumetti R, Diaz L., Savage G., Eggerth L.
(2005): Modern Composting Technologies, BioCycle,
Emmaus, USA, (ISBN 0-932424-29-5).
54
Table 6.3: Staff required for a three tons/day composting plant
Items Windrow and Box
Technique
Sorting
Sorting table (if favoured) 2
Buckets 6
Shovels 6
Rakes (long or short handle) 6
Composting
Watering pots 2
Thermometer 2
Sieving (two alternatives)
Flat frame sieve (Photograph
7.14, mesh size 8 and 16 mm)
2
Sieving drum (Photograph 7.15,
mesh size 8 and 16 mm)
1
Bagging
Bags (woven plastic bags, their
size is dependent on market
availability)
Depending on
requirements
Equipment for sealing bags Depending on
requirements
Miscellaneous
Brooms 6
Baskets 6
Uniforms, gloves, boots and
face masks
Two sets for each worker
Windrow
Technique
Box
Technique
Requirements
Manager/ Engineer 1 1 Graduate with management skills and willing to work with waste.
Responsible for monitoring mass flows, keeping records on plant
performance and accounting. Strategic planning and marketing if not
conducted by an external agent (e.g. NGO or company).
Collection workers (part-time) 4 4 Basic mechanical skills, responsible for maintenance and minor repairs.
Composting workers (full-time) 6 4 At least one worker should be literate, responsible for temperature monitoring
and recording.
Lab staff (optional) 1 1 Graduate with chemical background.
Marketing staff (optional) 1 1 Graduate in marketing and/or agricultural economics.
Task 7
Operating and Maintaining a Compostion Facility
Identifying Stakeholder Interests : Task 1
Assessing Target Community Interests and Land Availability : Task 2
Data Collection : Task 3
Preparing a Business Plan and Financial Projections : Task 4
Development and Design of Collection System : Task 5
Design and Construction of Composting Facility : Task 6
Operating and Maintaining a Composting Facility : Task 7
Marketing of Compost : Task 8
Composting comprises various steps starting from waste
sorting until the final bagging of the compost product. Task
7 gives guidance for the operation and maintenance of a
composting plant including aspects of quality control and
trouble shooting. The composting process can be divided
into nine steps which are shown in Figure 7.1 below. Waste
from households arriving at the composting plant is sorted
into several fractions. The organic fraction enters the
composting process. It is mixed with additives if necessary
and piled into the composting system. The composting
process has to be monitored by different parameters
(temperature, moisture). Finally, the mature compost is
screened and prepared for selling. Residues from sorting
and screening are recycled or disposed of.
Figure 7.1: Flow chart showing composting process steps and material
flows
After finalising the activities of Task 7 you will have been
informed about:
the different steps of a composting process
the required quality criteria for input material and
additives
how to measure important process parameters such
as temperature and moisture
how to maintain the compost plant
which are the typical problems of the composting
process and how to solve them
the most important quality criteria and how to control
them.
Activity 1: Operation and monitoring
Operational safety and health protection for workers should
be the priority concern. Workers should be obliged to wear
protective gear like uniforms, gloves and boots at any stage
when they are handling waste and compost.
Step 1: Sorting
Compost quality is mainly determined by the quality of the
input material. Hence, the sorting of the waste plays a vital
role. Substances which are not biodegradable need to be
separated from the biodegradable fraction. Sorting is
especially crucial with regard to hazardous materials. They
must be removed before the composting piles are formed.
Otherwise they will contaminate the entire pile and severely
compromise the final compost quality. Figure 7.2 shows the
classification of typical domestic waste and gives guidance
regarding which materials are suitable for composting.
If households are willing to segregate their waste at source
it saves a tremendous amount of time and costs for the
composting scheme. Moreover, it increases the quality of
both biodegradable waste and recyclables. Hence, the long
term goal should be the introduction of source segregation
of waste in households.
57
Task 7: Operating and Maintaining a Composting Facility
By the work one knows the workmen. (Jean de la Fontaine, 1621 - 1695)
Sorting of incoming waste
As soon as the mixed household waste arrives at the
composting site, it is separated manually into
biodegradable material, recyclables, and rejects.
Manual sorting can be done in different ways: on the
ground with a small rake (as practised in Dhaka,
Photograph 7.1) or on a sorting platform or table (see
Figures 6.2, 6.3 and 6.4). Workers must wear protective
gloves, boots and masks as they are in close contact with
the waste.
Rejects and recyclables are sorted into different buckets
and/or baskets. Recyclables are stored for sale in a shed.
Rejects are either disposed of in nearby municipal waste
bins or temporarily stored on-site before being
transported to the landfill.
The biodegradable waste fraction is further processed
inside the plant.
After having finished the sorting process, the sorting
platform is cleaned. No waste should remain overnight on
the sorting platform as it can attract vermin and cause
smell.
It depends on your local market which materials can be sold
as recyclables. In most cases at least a market for paper
and cardboard already exists. In other cities industries
processing glass, plastic or aluminium can be found. Check
the local market for prices and retailer networks. Generally,
industries only accept bulk delivery. If space is limited, it
might be more suitable to find a reliable middleman instead
of storing big amounts of recyclables on the composting
site.
Photograph 7.1: Sorting of incoming mixed household waste. Consider
the local habits: some prefer sorting on the ground, other prefer a table
or platform. (Waste Concern, Bangladesh)
Step 2: Mixing
The ratio of carbon (C) to nitrogen (N) - also called C/N ratio
- is very important for the biological degradation of organic
waste. Both C and N are feedstock for micro-organisms
responsible for the degradation of the organic matter. While
carbon is important for the cell proliferation, nitrogen is the
nutrient source. Annex 7 provides additional information
about the biological processes during composting. The text
explains the effects of a too high or a too low C/N ratio in the
composting process and how problems can be avoided.
The first assessment of the waste composition described in
Task 3 (Data Collection) already revealed the general
characteristics of the local solid waste. Generally one can
classify “green” materials as being high in nitrogen and
58
Figure 7.2: The quality of compost strongly depends on the input material. If source segregation cannot be implemented waste separation prior to
composting is necessary
“brown” materials as high in carbon. The input material
should have a carbon/ nitrogen ratio of 25:1 to 40:1 to allow
most rapid and efficient degradation of the organic material.
The wide range of the C/N ratio already indicates that a
certain variation of waste components is possible. It is
recommended to keep incoming “brown” waste (i.e. from
parks) separate from “green” household waste and to add it
later depending on the composition of the household waste.
For a start, these “green” materials and “brown” materials
are mixed in equal volumes. This ratio may need to be
adjusted if the composting process is not satisfying. For
instance, if the waste is very wet with little structure (e.g.
kitchen or restaurant waste) the fraction of “brown”
materials has to be increased (not only to correct the C:N
ratio, but also to reduce the moisture content and to
encourage the movement of air) Table 3.1 (in Task 3)
indicates that household waste is already close to the ideal
C:N ratio and normally needs just little additional “brown”
material high in carbon.
In practice, the ideal combination of wastes for composting
must be determined by trials. It takes some time to learn the
specifics of your local waste. Over time, the plant manager
will get a keen sense of how to mix the different incoming
waste types and when to add wood chips or animal manure.
Laboratory tests of your waste can assist in finding the ideal
ratio but are not crucial.
Photograph 7.2: Wood chips or saw dust is an ideal carbon source if the
waste is too wet and too high in nitrogen (Waste Concern, Bangladesh)
The right waste mixture in a nutshell:
An efficient composting process needs a C:N-ratio
within the range of 25:1 to 40:1.
Wood chips or sawdust (high C) or manure (high N)
may be mixed with the organic waste to optimize the
C:N ratio. Wood chips can also increase the pile
porosity, thereby improving aeration.
Organic screening residues from previous piles can be
added to fresh piles as a carbon source. As the
screening residues already contain micro-organisms,
they also accelerate the start-up of the composting
process.
Photograph 7.3: Thoroughly mix the waste before piling it onto the
aerator (Waste Concern, Bangladesh)
Step 3: Piling the Waste or Filling the Box
In Task 6 you already decided which composting system is
most appropriate for your requirements:
The Windrow Composting Method or
The Box Composting Method.
This previous decision determines the further handling of
the waste. Steps 1 and 2 described above are the same for
both systems, but the further handling of waste varies for
each system. Thus step 3 describes separately the
operation of the two systems.
Alternative 1: Preparing the windrows on aerators
The sorted organic waste is loosely heaped onto the
bamboo or plastic aerators (see Photographs 7.4 and 7.5)
and formed into long piles (windrows) as shown in
Photograph 7.6. The composting piles have a width of 1.6 m
and a maximum height of 1.6 m. The length depends on the
space available and the amount of incoming waste, but 2 to
3 m is generally recommended. The waste of 2 to 3 days
can thus be accumulated on one aerator. It is not
recommended to take more than three days to build a
windrow because this would lead to inhomogeneous
decomposition. The windrow shown in Photograph 7.6 has
a volume of approximately 5 m
3
and holds about 4 tons of
organic waste from two days of collection. This windrow
design allows sufficient oxygen supply and optimal heat
generation, maximising the decomposition rate of the
waste. The aerators and the restricted height and width
ensure sufficient oxygen supply and prevent the pile from
overheating. (Heat is developed in a compost pile that has
the right conditions of C:N ratio, moisture content and air
supply because huge numbers of bacteria are actively
feeding on the waste. More information about the
composting process can be found in Annex 8.)
59
Windrow Composting Method
In contrast to the typical windrow method the waste is
piled onto a triangular wooden or plastic rack allowing a
passive aeration of the compost pile. The additional
aeration from the bottom of the pile allows micro-
organisms to decompose the organic waste efficiently
through a better oxygen supply and improved temperature
control. Within 24 hours the micro-organisms within the
waste start to multiply and generate heat. Pile
temperature increases to 55- 65°C which is optimum for
aerobic composting. To enable the micro-organisms to
obtain sufficient oxygen, the pile is additionally aerated by
turning the waste from time to time (approximately once a
week). High temperature leads to water losses through
evaporation, so additional water must usually be added
with each turning. After 40 days of composting the
temperature has decreased, indicating a slowing down of
the process. As less oxygen is demanded, the raw
compost can be removed from the aerator and piled again
for the maturation phase without a central aerator. For
another 15 days mesophilic micro-organisms further
stabilise the compost leading to the final mature compost
product.
Box Composting Method
The box is constructed with perforated walls, a perforated
bottom grid and vent-pipes allowing air circulation through
the waste. (see Photograph 6.5 and Annex 4B) In contrast
to the aerator method, the sorted organic waste is daily
spread into the boxes in layers of 20 cm. The construction
of the box in combination with the layer technique ensures
sufficient aeration and additional turning is not necessary.
Air is supplied to the organic material through holes in the
walls and through the perforated vertical pipes embedded
in the pile. The perforated bottom of the box additionally
acts as drainage for excessive water. As in the windrow
system, the temperature within the mass increases within
a few days up to 60°C, ensuring that the final compost
product is free of viable pathogens or weed seeds.
Typically, a box is filled within 5-7 days and the waste in
the box decomposes aerobically for 40 days before it is
removed from the box. As with the windrow technique, the
compost needs another 15 days of maturing.
60
Photograph 7.8: A windrow after 40 days of composting and being
turned several times. The volume reduction is obvious (Waste Concern,
Bangladesh)
Photograph 7.4 and 7.5: The waste is piled around and onto the aerator
(height 1.5 m) (Waste Concern, Bangladesh)
Photograph 7.6: Fresh organic waste on the aerator with the bamboo
rack at the base (Waste Concern, Bangladesh)
Photograph 7.7: The windrow is turned weekly to improve the aeration
of the pile. The steam indicates the high temperature and water loss
during the composting process (Waste Concern, Bangladesh)
Alternative 2: Filling the composting boxes
The sorted organic waste is loosely spread in layers of 20
cm into the box, around the vertical aeration pipes. If one
box is not sufficient, the remaining waste has to be spread in
a second box. Assuming an input load of 3 tons or 5 m
3
of
organic waste per day and a box system as described in
Task 6, two boxes are filled within 5 to 6 days. The boxes
receive one layer of waste per day. Every time a layer is
added it is loosely mixed with the previous layer using a fork
or shovel. When the box is full the waste is left for 40 days
to go through a thermophilic composting process similar to
the windrow system. Frequently measure the temperature
inside the box following the procedure described below in
Step 5 (Temperature control). For measuring the moisture
weekly dig several holes into the compost and check the
moisture content according to the description of Step 6
(Moisture control) later in this chapter. If the material is too
dry spray water over the compost and level the material
again. After 40 days one side of the box is opened and the
fresh compost is removed from the box and stored as a pile
for further maturation. Apart from Step 4 (Turning of
Windrows) all steps below are the same for both aerator
composting method and box composting method.
Step 4: Turning of Windrows
One of the important factors during the composting process
is to ensure sufficient supply of air. Within a few days,
aerobic micro-organisms exponentially proliferate,
consuming an enormous amount of oxygen. A lack of
oxygen likely favours the growth of anaerobic organisms
which cause unpleasant odours. Furthermore, anaerobic
conditions slow down the degradation process resulting in a
longer composting period. Thus, attention must be given to
ensuring an adequate air supply.
The bamboo or plastic aerators already increase the
oxygen supply by passive aeration through the bottom.
Turning the material frequently as shown in Photograph 7.7
provides additional oxygen to the system as the waste
comes into contact with fresh air. The system described
here is based on manual turning like shown in Photograph
7.7. The composted material is removed from the aerators
with rakes, taking care not to damage the aerators. The
presence of steam is a good indicator of the effectiveness of
the composting process. Initially the material should be
turned 2 to 3 times per week as the composting process is
very active with a high oxygen demand and reaching
temperatures up to 70°C. When the temperature starts to
drop, the pile still needs to be turned every 10 days. In total
5 to 8 turnings within 40 days are necessary.
Turning has several advantages over a system that blows
air into a static pile of biodegradable material (Static forced
ventilation system):
It helps to keep the pile temperature within the optimum
range of 60 65°C: If the temperature becomes too high
the material remains spread out on the floor for about
fifteen minutes during the turning process before it is re-
piled (see Step 5 below, temperature control).
Turning ensures that all biodegradable material gets in
contact with air, thus avoiding “anaerobic zones” causing
unpleasant odour.
Water losses can better compensated for during turning,
ensuring a more even distribution of the added water.
Turning allows the less composted outer layer of the
windrow more chance of getting inside the pile, ensuring
a better hygienisation (killing of fly eggs and pathogenic
microorganisms) of the final compost. The waste should
be thoroughly mixed before it is re-piled.
The mechanical stress on the material favours a high
degree homogenisation of the entire waste material
leading to an accelerated process and an end product
with a finer structure.
Step 5: Temperature Control
Provided that the C:N ratio, the aeration and the moisture
content are all within the optimal range, the micro-
organisms multiply exponentially. This microbiological
activity results in a temperature increase to 6570°C within
1 to 2 days. (see Annex 7) Temperatures above 70°C need
to be avoided as they are too high for even thermophilic
bacteria and so inhibit the microbiological activity.
Temperatures above 80°C are lethal to most soil micro-
organisms and the process comes to a halt. Although
composting will occur at temperatures below 65°C, a
temperature of around 65°C favours rapid composting and
ensures the destruction of weed seeds, insect larvae, and
potential plant or human pathogens. Therefore, it is
preferable for the temperature of the composting pile to stay
at around 65°C for at least three days. After the first week,
the temperature gradually decreases and the
decomposition process slows down. The process moves
into the mesophilic phase (45 - 50°C) and other micro-
organisms take over the transformation until the waste
material is transformed into fresh compost.
61
Figure 7.3: Temperature curve showing the two composting phases:
thermophilic phase with frequent turning, maturation (mesophilic) phase
with occasional turning
62
Photograph 7.10 - 7.11: Two types of thermometers: Alcohol thermometer and electronic thermometer with stick probe (Sandec, Switzerland)
How to measure the temperature:
Use an alcohol thermometer and attach a string to the top
of the thermometer. (Do not use mercury thermometers
as the mercury can pollute the entire compost pile if they
break during measurement. Mercury belongs to the
group of heavy metals and is classified as a hazardous
substance.) If available, a digital thermometer with a stick
probe is preferable. (see Photographs 7.9 - 7.11)
If you use an alcohol thermometer for measurement,
firstly push a hole into the compost down to the required
depth within the pile using a broom handle or an
appropriate stick.
Then carefully lower the thermometer into the hole with
the string
Leave the thermometer in the compost for about 1 minute
then pull the thermometer out by the string and
immediately record the temperature.
Record the temperature trends twice a day at three points
within the pile – the top, middle and bottom of the pile or
the box. A template for recording temperature is given in
Annex 9.
Record the ambient air temperature as well.
Photograph 7.9: Temperature measurement with an alcohol thermometer
(Waste Concern, Bangladesh)
Step 6: Moisture Control
Microbes take up nutrients only as dissolved ions in a film of
water. Thus, the moisture content of the waste plays an
important role. To ensure rapid decomposition, maintain the
moisture content in the composting piles at a level of 40 to
60%. Ideally, water is only added during turning as the
material is spread out on the floor. Photograph 7.12 shows
the watering of a freshly made windrow in which the water
content in the outer layer was too low.
Photograph 7.12: Watering of a completed compost windrow (Waste
Concern, Bangladesh)
Figure 7.4 describes a quick test for moisture measurement.
Take a handful of compost and squeeze it hard. If only a few
drops of water appear the moisture content is in the optimal
range. If no drops emerge the moisture content is below
40%, indicating that the nutrient provision is hampered.
Consequently, the composting process slows down. Often,
the temperature of the waste pile decreases though the
process is not finished, because the water content is too low.
Adding water raises the temperature of the composting pile
and the decomposition process continues. (see also Step 7
below: maturity test) If the moisture content is too high, the
pile tends to become anaerobic and produces unpleasant
odors.
Figure 7.4: Testing of Moisture Content: Protect your hand with a glove.
Take a handful of compost and squeeze it in your fist.
A
: If no water is
squeezed out, the compost is too dry;
B
: If many drops can be squeezed
out, the compost is too wet;
C
: If few drops can be squeezed out, the
moisture content is ideal (CPIS,1993)
Wear protective gloves when testing the moisture
(squeeze test) for hygienic reasons and in case there
are sharp materials in the compost.
Add water during turning with a sprinkler until optimal
moisture content is reached.
The box system needs less water as the material is not
turned.
In some cases compost produce excessive water
(leachate) in the beginning of the process. This
leachate can be collected and reused for watering the
next pile.
Step 7: Maturing / Curing
After about 40 days, the material in the piles has a colour
like soil and the pile temperature has fallen below 50°C.
This indicates that the process has entered the curing or
maturing phase. Other micro-organisms and small insects
like caterpillars and bugs re-colonise the still immature
compost. Slowly, they further break down the more complex
organic materials like cellulose while producing substances
somewhat like topsoil. Additional three weeks are
necessary to ensure that the compost is mature and
suitable for direct application to plants (photograph 7.13).
During this phase the compost needs less oxygen and less
water. The temperature constantly goes down to the
ambient temperature.
Remove the fresh compost from the aerator or empty the
box.
Pile the fresh compost in the maturing area. The piles can
be moved closer together and piled higher (to a
maximum height of 1.5 m) to save space.
Turning is no longer necessary.
Only little watering is necessary, if the piles are very dry.
During the rainy season, keep the compost under a roof
to prevent it from getting soaked. Rain might leach
valuable nutrients from the compost.
Continue daily temperature monitoring until the compost
is at the ambient temperature. If the temperature of the
compost rises when water is added to it, the compost is
not mature and needs additional days for final curing.
The presence of white or grey colour indicates the
presence of fungi, which are important micro-organisms
for the composting process. Their appearance also
indicates that the pile is still in the mesophilic phase.
Mature compost appears dark brown, has an earthy smell
and a crumbly texture.
63