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Environmental Contamination from by-Products of Wet Coffee Processing

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Coffee diversity and knowledge
335
Environmental Contamination from by-Products
of Wet Coffee Processing
Solomon Endris1, Tesfu Kebede1, Behailu W/Senbet1, Worku Legesse2, Yared Kassahun1
Tesfaye Yakob1 and Abrar Sualeh1
1Jimma Research Center, P. O. Box 192, Jimma, Ethiopia
2Jimma University, School of Environmental Health, PO Box,307, Jimma, Ethiopia
Summary
Coffee effluents are the main source of organic pollution in environments where intensive coffee
processing is practiced without appropriate by-product management systems. The rise in the quantity
of wet processed coffee in southwestern Ethiopia has concurrently caused generation of huge amounts
of coffee effluents and other byproducts that directly pollute rivers and the surrounding environment.
Hence, the level of pollution in various rivers of Jimma zone because of coffee processing wastewater
was monitored from 2003 to 2005. In the study: physical, chemical, and biological indices of water
quality were employed. Physico-chemical parameters were recorded both in-situ and ex-situ. Trace
amount of NO3-was found at upper course of most rivers, while as high as 17.2 mg/l and 17.8mg/l were
recorded at downstream locations of Temsa and Bore Rivers. In addition, the average dissolved
oxygen, at the different sampling sites of the rivers varied between 7.97 (at upper course of Bore) and
0 (at lower course of Temsa) which shows the deterioration of water quality in locations below effluent
discharge points. Reduced pH values (as low as 2.1) were also recorded at downstream locations of
most rivers. In general, results of the analysis on pH, EC, DO, BOD, NH3, NO3 and other parameters
indicated a high level of pollution in almost all locations of the rivers below effluent discharge points.
Analysis of overall stream quality was also accomplished based on benthic-macro invertebrate
sampling. EPT richness, a commonly used bio-monitoring index, was used to assess the level of water
quality degradation in all rivers, which confirmed existence of a similar pattern of pollution in most of
the downstream locations. Substantial change in macro invertebrate community structure was noticed
which includes loss of pollution intolerant species in some downstream locations. Based on the data
obtained in this study, during the main processing season, downstream locations of these rivers cannot
be used safely for household purposes. Therefore, immediate intervention in the area of water
recirculation from coffee factories and other effluent management options should be dealt with top
priority to avoid further contamination of water resources and irreversible damage to the environment.
In addition, a favorable environment policy should be created to control and enforce the use of
available technologies that could reduce environmental contamination by coffee processing industries
in the region. Finally, this paper also includes various management options for coffee wastewater
compiled from international sources, which are deemed relevant to the prevailing environmental and
economic conditions of the region. Therefore, evaluating these management options for coffee waste
and selecting the most feasible ones requires strong attention and action from all concerned bodies in
the region.
Introduction
Coffee is produced in more than 50 countries providing income for approximately 25 million
smallholder producers (DFID, 2004; Oxfam, 2002), and employing an estimated 100 million people
(NRI, 2006). It is an important commodity, which is traded globally and at times, has ranked second
only to oil among traded commodities (Chanakya and Alwis, 2004). For Ethiopia, the birthplace of
coffee, it is both a defining feature of the national culture and identity, with 44% of all production
consumed domestically, and a cornerstone in the export economy and 50% - 60% of the country’s
foreign exchange is derived from the export of green beans (Mayne et al., 2002; World Bank, 2004).
Coffee is produced in many parts of the country under diverse agro-ecologies and production systems.
In the year 2001/02, an estimated 32145 tons of coffee has been produced in Jimma zone alone (CSA,
2002). Environmental issues have become serious issues both locally and internationally. Such issues
are also becoming more and more relevant to the coffee industry in Ethiopia since the current wet
coffee processing system is clearly associated with inefficient and poor waste management practices.
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It is known that there might be potentially detrimental environmental effects caused by the liquid and
solid by-products of wet coffee processing; hence, finding simple, economical, and sustainable ways
to overcome these problems has no alternative.
In Ethiopia, coffee is processed using either the wet or the dry method of processing. When properly
done, wet processing of coffee ensures that, the intrinsic qualities of the coffee beans are better
preserved, producing a green coffee, which is homogeneous and has few defective beans. Hence, the
coffee produced by this method is usually regarded as being of better quality and commands a higher
price. Therefore, production of wet processed Arabica coffee has sharply increased following the
establishment of numerous coffee washing stations in the south and southwestern parts of the country.
The rise in the number of wet processing plants has therefore resulted in the generation of huge
amounts of processing by-products, which have high potential of polluting the environment as long as
safe and efficient waste management practices are not followed. Coffee processing byproducts
generated from these wet coffee processing stations are usually damped either into nearby river or to
places where subsequent seepage of the effluent in to the rivers is highly likely. A considerable
amount of water is required during the wet method of coffee processing. An estimated 40 m3 of water
per tone of clean coffee is the required amount for receiving the cherries, transporting them
hydraulically in the pulping machine via the water current, removing the pulp, and sorting and re-
passing any cherries with residual pulp adhering them (Coste, 1992). Due to the high demand for
water during wet processing, processing stations are often constructed near permanent water sources
mainly rivers and streams, which makes the rivers more liable for contamination from the processing
wastewater.
Coffee effluent is acidic and has a high content of suspended and dissolved organic matter. Pulping
water with a high content of fermenting sugars using enzymes from the bacteria on the coffee cherry
and the water from fermentation or washing are the two types of wastewaters from wet coffee
processing. Coffee wastewater is rich in sugars and pectins and hence it is amenable to rapid
biodegradation (Chanakya and Alwis, 2004). However, other toxic substances (chemicals) found in
coffee wastewater like tannins, alkaloids (caffeine) and polyphenolics make the environment for
biological degradation of organic material in the wastewater more difficult.
The main pollution in coffee wastewater stems from the organic matter set free during pulping,
particularly the difficult to degrade mucilage layer surrounding the beans (Von Enden and Calvert,
2002). The composition of coffee pulp and mucilage is given below. The sugars contained in this
mucilage ferment and the organic and acetic acids from the fermentation of the sugars make the
wastewater very acidic, a condition in which higher plants and animals can hardly survive (Von Enden
and Calvert, 2002).
Research Findings
Pollution status of major rivers in Jimma zone
Physico-chemical indices
In-situ and ex-situ measurements of physicochemical parameters have been done on water samples at
different locations of rivers in Jimma zone (Figure 1). The result of physicochemical analysis
indicated degradation of water quality because of coffee processing effluent discharge in most of the
sampled streams (Tables 1). Most of the rivers were affected by coffee wastewater, but Temsa River
was the most polluted based on the physico-chemical parameters (Figure 2).
Conductivity
The minimum value of conductivity was found at Dembi River (60µS/m), while the highest was
recorded at Temsa (800µS/m) (Table 1). The average conductivity at sites above effluent discharge
points was 77µS/m, and the average conductivity of rivers below effluent discharge was 258µS/m. In
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337
general, there was a sharp increase in the conductivity of water samples at down stream locations
compared with samples from upper locations (Figure 3).
Figure 1. Location of sampling sites at rivers in Jimma zone, southwestern Ethiopia
Ammonia, Nitrate, and Phosphate
During the study period, the NH3, NO3, and PO43 concentration displayed large variation at locations
above and below effluent discharge points. The lowest ammonia concentration was zero at upper
locations and the highest was at the lower course of Temsa River with a concentration of 19.8 mg/l.
The mean NH3 concentration was 1.35 mg/l and 8.02 mg/l at the upstream and downstream locations
respectively. Similarly, nitrate concentration increased following effluent discharge (Table 1). Trace
amounts of NO3 were found at upper course of most rivers, while as high as 17.2 mg/l and 17.8 mg/l
were recorded at downstream locations of Temsa and Bore Rivers. The average NO3 concentration in
water samples from above discharge points for coffee effluent was 0.41 mg/l while in locations below
effluent discharge points it averaged 8.04 mg/l. Phosphate concentration also increased with the
discharge of coffee effluent in all rivers. In general, the average concentration of NH3, NO3, and PO43
increased at the lower course compared with the upper course of all rivers (Figure 4).
Oxygen, pH and temperature
The average dissolved oxygen, at the different sampling sites of rivers in Jimma zone, varied between
7.97 (at upper course of Bore) and 0 (at lower course of Temsa) (Table 1). The average dissolved
oxygen content was 6.98 mg/l and 4.69 mg/l for upstream and downstream locations, respectively. The
decrease in oxygen content is the main ecological effect of organic pollution in a watercourse into
which effluents have been discharged (Narasimha et al., 2005). The organic substances diluted in the
wastewater break down very slowly by microbiological process, using up oxygen from the water. Due
to the decrease in oxygen content, the demand for oxygen to break down organic material in the
wastewater exceeds the supply, dissolved in the water, thus creating anaerobic conditions (Von Enden
and Calvert, 2002). The temperature in the lower locations of most of the rivers was found to be higher
than the upper locations, with the average being 19.57OC for the downstream and 18.8OC for upstream
locations.
The lower course of rivers like Bore, Temsa, and Urgessa was very acidic (low pH). The lowest level
recorded (2.1) was at the lower course of Urgessa River while the upper course of most of the rivers
was above 7.0 (Table 1). The acidification of water in rivers below effluent discharge points indicates
that the active decomposition of organic matter in each of the downstream locations where the coffee
wastewater has been discharged or seeped. It is known that as the organic wastes oxidize, CO2 is
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338
released and increased acidic characteristics of the water by decreasing the pH value below the range
of 6.5 - 8.5, which is WHO standard for any source of water for human use (WHO, 2004). It is
important to note that the figures presented here describe the situation in the region during the main
coffee processing season that runs for about half of the year.
Table 3. Physico-chemical characteristics of water samples from rivers of Jimma zone at locations above and below coffee effluent discharge points
Sampling sites
DO
pH
To
NH3
NO3-
PO43-
BOD
U
L
U
L
U
L
U
L
U
L
U
L
U
L
U
L
Dembi
7.42
6.78
7.41
5.56
19.9
21
60
90
0.122
0.54
0.23
0.14
0.28
0.12
2.1
42
Wurssa
5.74
1.88
7
5.56
18.4
17.3
110
240
0.7
17.4
0.48
N.A
0.16
0.24
4.1
366
Dengaja
6.6
7.68
6.92
7.34
17.8
18.5
70
80
0
1.45
0.28
N.A.
0.19
0.18
2
13.3
Sunde
6.85
4.89
7.38
7
21.5
19.5
70
80
0
1.8
0.2
N.A.
0.54
0.1
2
16
Kolombo
7.02
6.24
7.35
7.18
15.3
19
70
90
0.34
1.2
0.4
0.28
0.19
0.38
5.2
5
Torbaho
7.13
5.11
7.61
7.14
19.2
N.A.
70
160
1.24
0.099
0.24
0.83
0.42
0.098
1.2
68
Bore
7.97
2.85
7.25
4.88
16.7
18.4
70
630
10.73
21.36
0.32
17.8
0.18
7.04
2.6
1200
Wanja
6.19
5.67
7.44
7.57
N.A.
18.8
80
90
0.342
0.25
1.2
N.A.
0.342
0.08
1
20
Temssa
7.41
0
5.95
4.3
18.8
23.8
100
800
0
19.8
0.32
17.2
0.29
9.9
3.1
1600
Urgessa
7.45
5.79
6.27
2.1
22.2
19.8
70
320
0
16.3
Trace
12
0.23
2.2
3.2
480
Average
6.98
4.69
7.06
5.86
18.87
19.57
77
258
1.35
8.02
0.41
8.04
0.28
2.03
2.6
381.0
Note: U = sampling points above effluent discharge; L = sampling points below effluent discharge. All units except temperature,
pH and EC are in mg/l.
Biological oxygen demand (BOD)
Biological oxygen demand (BOD) indicates the amount of oxygen needed to breakdown organic
matter in wastewater. BOD values obtained at locations below and above effluent discharge points of
the different rivers ranged from 1.0 mg/l (upstream of Bore River) to 1600mg/l (downstream of Temsa
River) (Figure 3). On average, BOD at locations above effluent discharge points was 2.66mg/l, while
at downstream locations it was 381mg/l (Figure 4), indicating deterioration of water quality in
downstream locations where coffee effluent is seeped in to the water course.
Figure 3. water quality of Temsa river above and below effluent disposal points
0
200
400
600
800
1000
1200
1400
1600
1800
Upper cours e Lower course
Sampling points
BOD and Conductivity
0
5
10
15
20
25
DO,pH,NH3,NO3,PO4,T
BOD (mg/L) EC (mS/m) DO (mg/L) pH
NH3 (mg/L) NO3- (mg/L) PO43- (mg/L) T (Oc)
2
3
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339
Figure 4. Average values of water quality parameters for all rivers above and below
coffee effluent discharge points
0.00
5.00
10.00
15.00
20.00
25.00
Upper cours e Lower course
Sampling points
DO,pH,T
0.00
50.00
100.00
150.00
200.00
250.00
300.00
350.00
400.00
450.00
EC,BOD
DO (mg/L) pH TO (OC) EC (mS/m) BOD (mg/L)
Figure 5. Average concentration of NH3, NO3, and PO4 in all rivers above and
below coffee effluent discharge points
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
Upp er course Lower course
Sampling points
mg/L
NH3 NO3 PO43-
Biological monitoring
Benthic macro invertebrates are aquatic insects, such as mayflies, caddisflies, riffle beetles, and
midges, and other invertebrates that live on the stream bottom. Benthic macro invertebrates are useful
in evaluating water quality of streams because their habitat preferences and low motility cause them to
be affected directly by substances that enter the aquatic system (Reif, 2002). Macro-invertebrates are
sensitive to different chemical and physical conditions. If there is a change in the water quality,
perhaps because of a pollutant entering the water, or a change in the flow downstream of a river, then
the macro-invertebrate community may also change (Water facts, 2001). Various bio-monitoring
indices have been developed and employed to monitor water quality of rivers and streams. Taxa
richness is a measure of the number of different kinds of organisms in a collection. It measures the
overall diversity of the biological community sampled. EPT taxa richness is the total number of taxa
within the “pollution sensitive” orders Ephemeroptera (mayflies), Plecoptera (stoneflies), and
Trichoptera (caddisflies). Taxa richness and EPT taxa richness will decrease with decreasing water
quality (Reif, 2002).
The richness of macro-invertebrate community composition in a water body can therefore be used to
estimate the level of pollution or contamination of rivers and streams in a region. Hence, during the
study (2003 2005) identification of all macro invertebrates in each specimen has been carried out to
the family level. However, only three orders namely Ephemeroptera, Plecoptera, and Tricoptera,
which are known to be highly sensitive to pollution, are reported in this paper (Table 2).
3
4
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The present study analyzed the community changes along a pollution gradient (upper and lower course
of the rivers), and showed that changes were significant and comprehensive in terms of the parameters
used. Orders of Ephemeroptera, Plecoptera and Tricoptera are known to be good indicators of organic
pollution for they are sensitive to the oxygen budget of a given water body. From the upstream and
downstream distribution of macro-invertebrates, it is evident that generally these three orders decline
in abundance and diversity downstream relative to upstream sites (Table 2). This supports the accepted
view that sensitive species are reduced when water quality deteriorates (Reif, 2002).
Table 2. EPT Taxa richness (number) at locations above and below coffee effluent discharge points in different rivers of Jimma Zone.
Sampling sites
(Rivers)
Ephemeroptera
Plecoptera
Trichoptera
Upper course
Lower course
Upper course
Lower course
Upper course
Lower course
Gindo
4
1
-
-
-
-
Dembi
79
-
15
-
1
-
Wurssa
2
2
-
-
-
-
Sunde
81
3
28
-
-
-
Dogaja
61
14
-
6
-
-
Kolombo
35
31
18
-
1
-
Torbaho
74
-
4
-
-
-
Bore
-
-
-
-
-
-
Wanja
29
44
14
-
1
-
Temssa
-
-
-
-
-
-
Urgessa
125
-
2
-
-
Suggested Effluent Management Options
Various techniques that could either solve the pollution problems associated with coffee wastes or
significantly reduce the risks of pollution have been developed, tested, and used in different coffee
producing countries. The different coffee waste management techniques and practices discussed in this
paper are compiled from the experience of coffee producing countries such as India, Vietnam,
Nicaragua, Costa Rica, and Kenya. As outlined by researchers working on the issue of coffee
wastewater management, the development of solutions for pollution reduction is best effected by the
concept of waste minimization followed by treatment, rather than the alleviation of the present
problems by treatment alone (Mburu, 2001, 2004; Chanakya and De Alwis, 2004). The utilization of
the processing wastes is another potential option for pollution control.
Many approaches have been tried in different coffee producing countries to get the pollution load
under control. Anaerobic settling ponds, artificial aeration, biogas reactors, land application by
irrigation or wetlands are used.
Reducing water use and wastewater generation
It is known that factories, which try to practice some form of water conservation, can usually get their
water usage down to around 6 cubic meters per ton of cherry or less. The fully washed method with no
recirculation of water and an included fermentation step requires more water than the process of
mechanical mucilage removal producing semi-washed coffee. In practice, 1 to 15 m3 of fresh water per
ton cherry have been reported from international sources. Von Enden and Calvert (2002) indicated that
most of the Arabica coffee in Vietnam is processed in a centralized way by mechanical mucilage
removal. Such a centralized setup of processing lines produces medium quantities of highly polluted
wastewaters for around 4 months in the year; where wastewaters are normally discharged untreated
into small waterways causing serious environmental problems. To control effectively the problem of
wastewater, it is usually advised to keep the amount of effluents as small as possible so that it will be
easy to treat the water in an appropriate way without requiring too much space for ponds. Therefore,
the recycling of used water is strongly advised for both fully washed and semi-washed coffee.
Coffee diversity and knowledge
341
Reduction of coffee wastewater generation by reducing water use can be achieved by full recirculation
of the processing water. Recirculation of pulping water conveys wastes further away from the surface
water and to easy points of utilization. Besides effluent reduction, recirculation of pulping water
speeds up fermentation and makes the process effectively completed such that there is usage of less
water for intermediate and final washing (Mburu, 2004). As a measure leading to reduced water use,
reuse of pulp water for a few cycles prior to discharge, deployment of new machinery that use less
water, and eliminating a few fermentation steps have been adopted voluntarily by coffee processing
units in India (Chanakya and De Alwis, 2004). Similarly, a large reduction in wash water has been
achieved with an overall reduction in water use.
Using water efficient machinery
The development of new pulpery devices with reduced water usage has marked a significant
contribution in the ongoing effort to alleviate coffee wastewater problems. A new water efficient
pulper device developed by Cenicafe (www.cenicafe.org) reduced water usage in on-farm processing
from 8 to < 1 l/kg of fruit processed (Chanakya and De Alwis, 2004). Such water efficient machines
have not yet penetrated in to the Ethiopian market, neither did they in markets of other major coffee
producing countries. However, this is a solution helps to reduce coffee waste generation and
subsequent pollution.
Alternative uses
In coffee producing countries, coffee wastes and by-products constitute a source of severe
contamination and a serious environmental problem. For this reason, since the middle of the last
century, efforts have been made to develop methods for its utilization as a raw material for the
production of feeds, beverages, vinegar, biogas, caffeine, pectin, pectic enzymes, protein, and compost
(Rathinavelu and Graziosi, 2005). The use of fresh or processed coffee pulp has been the subject of
numerous studies, which, in general, lead to the conclusion that coffee by-products and wastes can be
used in a variety of ways. The various utilization options of coffee processing wastes would have
significant contributions to the overall effort of reducing or avoiding environmental contamination
from wet coffee processing plants. Recycling the coffee pulp mulch or more importantly as organic
fertilizer improves the soils fertility and contributes to minimize the risk of environmental
contamination.
In Kenya, effluent can be used legally for irrigation by passing it through methane gas producing
chambers first to render it less ‘raw’ and to produce gas (Mburu, 2001). In a study that examined the
current coffee production and processing systems in Costa Rica, Adams and Ghaly (2006) indicated
that coffee wastewater could be used for the production of biogas, fish, and animal feed. In addition,
the cultivation of mushroom on pulp and wastewater has been tried in El Salvador. Coffee wastewater
treatment technologies Chanakya and De Alwis (2004) described two strategies in wastewater
management: pond/ lagoon-based treatment of wastewater and discharge into water bodies; and
treatment of wastewater and re-use on coffee and other crops. The use of stabilization ponds has
emerged as the most preferred option in India where direct discharge to water bodies is not practiced
(Chanakya and De Alwis, 2004). However, various reports indicated that the use of these ponds and
lagoons is still not being followed in an acceptable ‘scientific/ best practices’ manner. In Kenya,
stabilization ponds operated improperly have become breeding sites for disease-spreading mosquitoes,
emit unpleasant odors, and cause other nuisances (Gathuo et al., 1991). Wastewater management
techniques used by coffee pulping stations in many countries are based on the use of lagoons.
Chanakya and De Alwis (2004) indicated that the practice is also popular in India, a treatment process
based on the use of anaerobic (21 days) and aerobic (7 days) lagoons after an initial chemical
pretreatment (neutralization).
Various wastewater treatment technologies have been developed and tested in different coffee
producing countries with the view to reduce or alleviate coffee wastewater related pollution problems.
Evaluation result of four technologies considered appropriate within the context of Kenyan and other
Processing and quality
342
similar countries have been reported by Mburu (2004). These are existing Kenyan Seepage Pit
Technology, the “leeds” seepage trench, anaerobic stabilization ponds, and upward flow anaerobic
sludge blanket (UASB) reactors. Of the approaches tested, anaerobic ponds were least suitable due to
difficulties in managing the pH level, despite high COD and SS removal rate.
Seepage pits
Much of the treatment capacity of a pit is by seepage of effluent through the soil before it reaches the
river (Mburu, 2004). Maximizing the distance between the pit and the river is therefore important in
achieving the intended goal. It is also advised that containing walls be planted with appropriate
vegetation which can strengthen the soil through an extensive root system. To operate well the
sidewall of a pit should not be compacted soil as compaction reduces the ability of the effluent to
percolate through the wall into the surrounding soil. In deciding on the size and number of pits, the
quantity of effluents generated in the area should be considered carefully. The correct operation and
maintenance of a pit will greatly improve its performance.
Seepage trench
From a study conducted in Kenya, the seepage trench was found to be the most appropriate technology
to deal with coffee effluents. The treatment capacity of a trench is higher than that of a pit because of
the larger infiltration area to volume ratio. The trench should be as deep and as narrow as possible to
maximize the infiltration area whilst minimizing the land use. Trenches are more suited to a wider
range of site condition than pits. For instance, trenches can be built on sites with a greater gradient
than which suit pits (Mburu, 2001).
Conclusion
Results of the physicochemical characterization and biological monitoring of streams in the region
emphasized the urgent need for a sound effluent management options in order to ensure sustainability
of coffee production and to avoid irreversible environmental damage.
Water quality deterioration due to coffee effluent disposal have been clearly demonstrated by the
combination of high acidity, high BOD, low DO and low EPT richness in downstream locations of the
streams monitored during the study. It is therefore very crucial to evaluate and select the most
appropriate coffee waste management options discussed in this paper focusing on the technologies that
do not demand excessive land area; that are not capital intensive, that do not require sophisticated
operating and monitoring regimes and that necessitate a low level of infrastructure support.
Further activities (experiments) that would assist the coffee industry to benefit from the niche markets
that reward higher valued coffee in terms of quality or socio-environmental consciousness, and help
policy makers to concentrate on timely and relevant issues are strongly advised to be included in the
research agenda of the center.
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Coffee Diversity & Knowledge
Edited by
Girma Adugna
Bayetta Bellachew
Tesfaye Shimber
Endale Taye
Taye Kufa
© EIAR, 2008
ኢግምኢ 2000
Website: http://www.eiar.gov.et
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P.O.Box; 2003
Addis Ababa, Ethiopia
ISBN: 978-99944-53-21-4
Proceeding of a National Workshop
Four Decades of Coffee Research and Development in Ethiopia
14 17 August 2007, Addis Ababa (Ghion Hotel), Ethiopia
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Article
Over 120 000 tons coffee is processed per year in Kenya. More than 1200 coffee factories produce a pollution loading equivalent to a staggering population equivalent of over 240 000 000. The coffee industry is therefore the most important industrial polluter in rural Kenya. Pulp, husks and wastewaters are produced. Husks can be directly used as fuel. Wet pulp could be composted and then used as a soil conditioner. Wastewaters have a high BOD5 sometimes even exceeding 9000 mg/l. In India and Central American countries, anaerobic lagoons are mainly used for the treatment of these wastewaters. In Keftya water re-use combined with land disposal with zero discharge has been recommended. However, in all these methods, the desired environmental soundness is rarely achieved. Anaerobic digestion with biogas production is potentially attractive. Fuel generated could be used for drying coffee. About 10 000 GJ of energy is required to dry 1 ton of coffee. The potential yield of biogas from one ton of pulp can be estimated as 131 m3. This is equivalent to 100 litres of petrol in fuel value.
Book
We live in an era of constantly accelerating scientific and social change brought about by developments in education, technology and modem communication. This is a time of questioning and new perceptions affecting all facets of our daily lives. With increasing frequency issues are being raised which demand answers and new approaches. This increases the responsibility of those involved in determining the future shape of the world of coffee. The dependence of developing countries on income generated from trade in coffee, the emergence of new processing techniques, health implications and questions of quality of coffee in the cup are among the issues related to coffee. The knowledge required to form the basis to resolve these issues for the benefit of the multitudes of coffee drinkers will be generated only through the systematic build up of information and its subsequent evaluation. Science and modem technology provide essential tools for these endeavours. This book should act as a stimulant to thought and creativity so the issues facing the industry may be fully analysed and a healthy future for coffee secured. It marks a step forward in laying the foundation for coffee's future. Alexandre F. Beltrao Executive Director International Coffee Organisation London PREFACE We have long been fascinated by coffee and on many occasions bemoaned the lack of a comprehensive text dealing with the varied scientific aspects. With the encouragement of Tim Hardwick of Croom Helm Ltd, we decided to pool our resources and produce just such a multi-author volume.
Article
The paper examines the broader environmental issues and environmental management aspects of primary coffee processing in general and more specifically how it is addressed in India. Primary processing, the production of green beans from the coffee fruits, is practised to bring out more flavour. Coffee is an important global commodity, yet seen from a systemic view the producers and consumers of such an important commercial commodity are far apart. Primary coffee processing, with all its attendant environment impact, takes place at the producer end. The consumers in general are unaware of these impacts. The various methods of processing, the processing steps and the waste discharge associated with them are reviewed. A review of pollution and associated management methods is presented. An anaerobic bioreactor design developed and tested in a few Indian coffee plantations as a simple solution is also described.
Article
The present study used a new model to analyse macroinvertebrate community changes along an organic pollution gradient in the River Trent system, U.K. The model divides community changes into four types, three of which are further differentiated into two sub-types. These type and sub-type variations are of different ecological significance. The results showed that as water quality deteriorated, species loss, the average abundance of sample-specific species and the average maximum ratio of in-common species abundance increased substantially, while the numbers of persisting species were reduced rapidly. However, polluted sites were also found to gain some tolerant species, particularly at slightly polluted sites. The abilities of several commonly used biotic indices to summarise these changes were compared. The design of the Chandler score system appeared to be more effective than the other systems examined. The Chandler-ASPT was modified by multiplying by log S (species richness/the number of key taxa) to improve its sensitivity over the lower range of water quality while retaining its effectiveness over the upper range of water quality. The modified index was tested using a published data set.
Article
The aim of this study was to examine the current coffee production and processing system in Costa Rica in order to maximize its sustainability through cost and risk reductions and identification of new opportunities. A two-year field investigation was performed for assessing resource, energy and water uses, characterizing by-products, and evaluating training, management and industry structure, with the aim of identifying opportunities for the implementation of Cleaner Production (CP) and industrial ecology (IE) strategies. The application of industrial ecology has been implemented in a piecemeal fashion and has not, therefore, been widely accepted by the industry at large. The broader coffee production system in Costa Rica does not encourage the practice of environmentally sustainable methods within production or processing, and does not encourage the exploration of niche markets that reward high-valued coffee in terms of quality or socio-environmental consciousness. Changes in industrial throughput, operational design, and management attitudes are needed to ensure sustainability within the industry. A number of opportunities for maximizing the sustainability of the coffee industry exist through: (a) strategic application of Cleaner Production, (b) effective use of resources, (c) alternative use of by-products, (d) efficient operational design, (e) training, (f) introduction of basic environmental management concepts, and (g) changes to industry structure. The paucity of data regarding research into the specific barriers to innovations within the coffee industry requires investigation. The specific barriers to the application of environmental innovations need to be identified and understood. This must include the social, cultural and institutional aspects governing the industry in addition to the technical and economic aspects normally addressed.
Article
This paper reviews the history and development of biological water quality assessment using macroinvertebrates in Europe, and critically evaluates each of the principal approaches used. As the biotic approach incorporates the most highly regarded features of the saprobic and diversity approaches, it has received the most attention in recent years. Most modern biotic index and score systems have evolved from the Trent Biotic Index, through a series of refinements and adaptations (i.e. the Extended Biotic Index, Chandler's Score, Indice Biotique) into the two modern systems. These methods are the Biological Monitoring Working Party System, used mainly in Great Britain, and the Belgian Biotic Index Method. The results of these techniques are now influencing policy decisions concerning surface water management in Europe, where macroinvertebrate community assessment are being used as a planning tool for managing water uses, for ambient monitoring, and for evaluating the effectiveness of pollution control measures. New research directions aimed at improving the performance of bioassessment techniques are being explored. These include defining reference communities based on stream typology which can then be used to set water quality objectives, and applying these methods to the assessment of toxic pollution.
Coffee: the plant and the product
  • R Coste
Coste, R. 1992. Coffee: the plant and the product. Macmillan press limited, London.
  • B Gathua
  • P Rantala
  • R Maatta
Gathua, B., Rantala, P. and Maatta, R. 1991. Coffee Industry Wastes. Water Science Technology, Vol. 24, No. 1: 53-60
Crisis in the Birthplace of Coffee, Oxfam international research paper
  • R Mayne
  • A Tola
  • G Kebede
Mayne, R, Tola, A, Kebede, G. 2002. Crisis in the Birthplace of Coffee, Oxfam international research paper, Oxfam International.
The Environmental Considerations Featuring in the Processing of coffee in Kenya
  • J K Mburu
Mburu, J.K. 2001. The Environmental Considerations Featuring in the Processing of coffee in Kenya, 19 th International Conference on coffee Science, ASIC, May 14 to 18, 2001, Trieste, Italy.