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Aerobic vs Anaerobic Composting: Differences and Comparison



In recent decades the increased harmful effects of agro-chemicals and synthetic fertilizers both in plant and animal health have created awareness about the use of organic inputs in agriculture. These increased demands of organic inputs have raised concern about the management of waste material through different composting techniques. Therefore, to meet out the demand for organic produces, there is a need for better understanding of composting methods. In this article, comparisons between aerobic and anaerobic composting processes have been discussed. Also, a comparative analysis of both the methods in terms of microbes involved, decomposition process, gaseous emission and superiority in pathogen suppression under both the processes have been discussed.
Food and Scientific Reports
February 2021Volume: 2, Issue: 1Page23
Amrit Lal Meena1, Minakshi Karwal2, Raghavendra KJ3 and Ekta Narwal4
1&3ICAR-Indian Institute of Farming Systems Research, Modipuram, Meerut-250110; 2KIET group of Institutions, Ghaziabad, Delhi-NCR,
India-201206; 4ICAR-Indian Agricultural Research Institute, New Delhi, India-321303.
In recent decades the increased harmful effects of agro-chemicals and synthetic fertilizers both in plant and animal health
have created awareness about the use of organic inputs in agriculture. These increased demands of organic inputs have raised
concern about the management of waste material through different composting techniques. Therefore, to meet out the
demand for organic produces, there is a need for better understanding of composting methods. In this article, comparisons
between aerobic and anaerobic composting processes have been discussed. Also, a comparative analysis of both the methods
in terms of microbes involved, decomposition process, gaseous emission and superiority in pathogen suppression under both
the processes have been discussed.
Keywords: Aerobic, Anaerobic, Compost, Decomposition, Gaseous emission, Pathogens.
In recent decades, expansion of agricultural area
and increased pollution level in agricultural produces due
to unbalanced use of agro-chemicals and synthetic
fertilizers has lead to the use of compost in agriculture.
Composting can be defined as decomposition/
mineralization followed by partial humiliation of organic
materials by the biological metabolic action of
microorganisms i.e. bacteria, fungi, actinomycetes etc.
under optimum conditions over a period of time to a stable
end product. The end product is known as compost. Many
types of organic matter, such as leaves, straw, fruit and
vegetable peelings and manures can be used to make
compost. The degraded end product is completely
different from the original organic materials which have
characteristics of dark brown colour, crumbly in nature
with a pleasant smell (Mehta and Sirari, 2018; Meena et
al., 2021). Being easily available, cost-effective and easy
to prepare, compost is an important source for
improvement of soil and crop quality. Compost improves
the structure of the soil. It allows more air into the soil
improves drainage and reduces erosion. Compost helps to
stop the soil from drying out in times of drought by
holding more water. Compost helps in improvement of
soil physico-chemical properties as it adds the nutrients to
the applied soils as well as acts as a binding agent for the
soil particles; thus, increase the nutrient availability for
the plants. Based on the nature of microorganisms
involved in the decomposition process of organic wastes,
composting can be divided into two broad categories i.e.
aerobic and anaerobic.
Aerobic Composting
Decomposition of organic matter using microorganisms
that require oxygen is known as aerobic composting.
These microorganisms are inhabited naturally in the
moisture surrounding organic matter. The oxygen diffuses
in the moisture from the air is utilized by the aerobic
microorganisms for their respiration and other metabolic
activities. As a result of aerobic decomposition carbon
dioxide (CO2), water and heat are released as by-products.
Production of heat in aerobic decomposition accelerates
creation of micro-environments within the compost heap
which helps in killing catastrophic pathogens and bacteria
due to non-adaptability of these harmful organisms to
these environmental conditions. These environmental
conditions also help in proliferation of diverse bacterial
species i.e. psychrophilic, mesophilic and thermophilic.
These microorganisms are basically classified as: First
level decomposers, second level decomposers and third
level decomposers (fig. 1).
Fig.1. Types of different organisms involved in composting process (Source: Farm
First level Decomposers eat
organic material Second level Decomposers
eat level one organisms Third level Decomposers Eat
level two organisms
Bacteria, fungi
mites and
Ants, beetles, centipedes,
worms, flies, milipedes,
slugs, snails, spiders,
Aerobic composting versus Anaerobic composting:
Comparison and differences
Food and Scientific Reports
February 2021Volume: 2, Issue: 1Page24
First level Decomposers
The first level decomposers consist of the small
size microorganisms that shred the organic material and
eat the shredded organic matter, basically, the bacteria
(Bacillus coagulans, B. megaterium, B. subtilis, B.
sphaericus, B. licheniformis, B. circulans, Arthrobacter,
Alcaligenes faecalis, Bacillus brevis, B. pumilus,
Pseudomonas sp., Streptococcus sp., Thermus sp.), fungi
(Aspergillus fumigatus, Basidiomycetes sp.,
Humicoligrisea, H. insolens, H. lanuginosa, Malbranchea
pulchella, Myriococcum thermophilium, Paecilomyces
variotii, Papulaspora thermophilia, Penicillium dupontii,
Scytalidium thermophilim, Termonmyces sp., Tricoderma
sp.) and actinomycetes (Streptomyces, Frankia,
Actinomycetes micromonospora and other 14 species)
which play a crucial role in composting process. These
microorganisms through their metabolic chemical
reactions breakdown the complex organic materials into
different simple organic materials (Fig. 2) (Mehta et al.,
Fig. 2. Stepwise degradation of various organic matter
components by different level of microbes
Second level Decomposers:
The second level decomposers inherited by
nematodes, mold mites, beetle mites, springtails and
protozoa which decompose the organic material and eat
the organisms of first level decomposers. These organisms
are small in size and use of stereoscopic microscope or
hand lens is useful to scrutinize them in details.
Third level Decomposers:
The larger creature generally known as macro-
organisms i.e. beetles, ants, centipedes, millipedes, flies,
snails, slugs, composting worms and woodlice (sow bugs)
physically break down the composting materials into
small pieces through their tearing, chewing and sucking
actions. These organisms can be seen through naked eyes
(Bernal et al., 2009).
Anaerobic Composting
Anaerobic composting generally takes place in
nature. Composting which progresses without the
entanglement of oxygen is known as anaerobic
composting. In this process, the organic material is
breakdown by the different species of anaerobic
microorganisms. Like aerobic microorganisms, anaerobic
microbes also employ the N, P, K and other nutrients for
their metabolic development. The major differences
between aerobic and anaerobic composting are:
breakdown of organic nitrogen to ammonia and organic
acids; release of methane (CH4) from the decomposition
of carbon compounds (Jiang et al., 2011). Reduction is the
main process of breakdown of organic matter under
anaerobic composting, though for a shorter period of time
oxidation also takes place for preparation of final end
product in anaerobic composting. There are four major
stages of anaerobic decomposition i.e. Hydrolysis,
acidogenesis, acetogenesis and methanogenesis.
In hydrolysis which is the first stage, the
insoluble complex organic materials i.e. cellulose,
hemicelluloses, lignin etc. are hydrolysed into the soluble
simple amino acids, fatty acids and sugars. The hydrolysis
process has a significant stage in anaerobic composting as
it decomposes the raw organic matter with high complex
organic content. The fermentative acidogenic bacteria
further decompose the remaining complex organic matter
into simple molecules under the acidogenesis process
which is the second stage of anaerobic composting. In the
third stage i.e. acetogenesis, simple organic molecules
created by the acidogenesis process are further digested to
acetic acid, carbon dioxide (CO2) and hydrogen. The
microbes involved in acetogenesis process are:
Acetobacter woodii, Clostridium aceticum and
Clostridium termoautotrophicum. Production of methane
gas (CH4) by methane forming microbes i.e.
Methanosarcina takes place in the fourth and final stage
which is known as methanogenesis (Mehta and Sirari,
Aerobic versus anaerobic composting
The consumption and decomposition of organic
matter by the microorganisms have broadly been
categorized into two categories: first one that require
oxygen (aerobic) and those that don’t require oxygen
(anaerobic). Though many studies have considered
anaerobic composting as a suitable alternative to aerobic
composting due to minimized loss of nitrogen in
anaerobic composting (Yu et al., 2015). But the aerobic
composting has considerable advantages over anaerobic
Food and Scientific Reports
February 2021Volume: 2, Issue: 1Page25
composting i.e. rise in the temperature of the pile as high
as up to 60ºC-70ºC which helps in killing of weed seeds
and pathogens; aeration increase the decomposition rate of
the organic material; shorter period of time requires for
compost preparation and the intensity and number of
objectionable emissions are distinctly reduced (Gill et al.,
2014). Three main broad categories have been identified
between aerobic and anaerobic composting i.e.
Decomposition; pathogen suppression and emission of
Turning and proper aeration increase the
decomposition rate of organic material in aerobic
composting compared with anaerobic composting. For the
proper decomposition of organic material, it should be
kept at least for six to twelve months in anaerobic
composting while; a time of period of 30 days to 120 days
is far enough for complete decomposition of organic
material in aerobic composting (Tian et al., 2012).
Pathogen suppression
Microbes are the essential component of
composting both in aerobic and anaerobic methods.
Presence of diversified microorganisms in aerobic
composting raises the compost pile temperature up to
60ºC-70ºC which is far enough to kill the harmful
pathogens and weed seeds present in the composting
materials. Whereas, on the other hand, the low
temperature and presence of specific species of
microorganisms in anaerobic compost are unable to kill
the pathogen and weed seeds and they remain in the
composting material. It has been observed by several
studies that presence of 50-70ºC temperature and 35%
moisture level in aerobic composting is high enough to
kill the weed seeds of pigweed, barnyard grass, kochia etc.
Also, several pathogenic fungi species viz. Olpidium
brassicae, Fusarium oxysporum, Plasmodiophora
brassicae, Synchytrium endobioticum, Phytophthora
infestans and various bacterial plant pathogens are unable
to survive at the higher temperature generated during the
aerobic composting (Mehta et al., 2016). Thus, it has been
observed that the optimum exposure of the composting
material at high temperature is required for preparation of
pathogen free compost. All these beneficial effects
support the importance of thermophilic phase of aerobic
composting compared with the anaerobic composting
where the temperature level never reaches up to 65ºC.
Gaseous Emission
In both aerobic and anaerobic composting
processes some unpleasant odours emitted from the
composting materials which are generated due to rapid
microbial degradation of complex organic matter into
simple compounds. The extent and intensity of odours
emission are high in aerobic composting as compare to
anaerobic composting but rapid turning and frequent
supply of oxygen in aerobic composting decrease the
chances of evolution and emission of unpleasant gases
whereas, because of closed systems and low level of
oxygen causes higher formation and emission of
unpleasant gases in anaerobic composting (Jiang et al.,
2015). Application of various chemical and biological
treatments can reduce the emission of these gases from the
composting materials. Thus all the above discussed
benefits support the superiority of aerobic composting
over the anaerobic methods.
The main aim of this article was to discuss the
types of composting, microbes involve in composting
processes and comparison between the aerobic and
anaerobic composting methods. Both aerobic and
anaerobic composting techniques have significant
environmental impacts through management of the waste
materials which include: management of VOC (volatile
organic compounds) and odour emissions and killing of
pathogens and weed seeds. It has been clearly found out
that rapid turning and presence of oxygen fasten the
composting process in aerobic composting compared with
the anaerobic method.
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Residual municipal solid waste (RMSW) is a rapidly expanding problem worldwide and a good waste management system could reduce concerns about its correct treatment. The purpose of this study was to characterize RMSW from urban and rural areas with the ultimate goal of estimating the recycling potential of the identified fractions and implementing waste collection and recovery methods according to the type of area that generates them. A direct sampling campaign of RMSW was performed. The results showed that the highest organic waste rate was found in the rural area (11.9%); urban-area-produced RMSW mainly constituted recyclable fractions such as plastic (26.3%), paper (21.8%), glass (3.5%) and metals (3.3%). The physical-chemical characteristics of RMSW showed levels of heavy metals below the detection threshold. The conditions necessary for composting could be met only for the organic fraction coming from rural areas as demonstrated by a pH value of 6.9 and a moisture content of 46.5%. These data will be extended to all the urban and rural areas to design appropriate disposal and/or recovery plants with profitable economic interventions that will lead to a reduction in costs in the planning of the integrated solid waste management.
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The implementation of a suitable and ecologically friendly solid waste management plan is accepted as an essential need. Given that organic matter constitutes the majority of solid waste, composting has gained popularity as an alternative way of organic refuse recycling. Compost quality is defined by its stability and maturity, both of which must be assessed by measuring a large number of physical–chemical parameters, microbiological variables, and enzymatic activities. These procedures are complex and time-consuming, making it difficult to assess compost quality correctly. Spectroscopy methods could be used as an efficient alternative. In this work, general information about composting processes and near-infrared spectroscopy (NIRS) is given. A discussion and comparison of the different approaches of coupling NIRS and chemometric tools for the monitoring and/or control of composting processes are presented in this work.
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Organic waste management is a major global challenge. It accounts for a significant portion of waste that ends up in landfills, where it gradually decomposes and emits methane, a harmful greenhouse gas. Composting is an effective method for potentially solving the problem by converting organic waste into valuable compost. Despite many studies focusing on the composting process, no study has reviewed the technological advancements in the composting fields from the perspective of patents. This review paper begins with background information on the composting process, specifically important factors affecting the process, problems associated with it, and the available technologies to facilitate the process. Different technologies are discussed, ranging from manual to automated methods. Subsequently, 457 patents are selected, classified into different categories, and reviewed in detail, providing a patent technology landscape of composting technology. Automatic composters are more prominent than manual ones as managing organic waste at the source has become more crucial in recent years. The need for a domestic composter creates an opportunity for the development of a compact and automated system for organic waste management, which is more suitable for urbanized settings. This technology has the potential to reduce the amount of organic waste that needs to be managed at an already overburdened landfill, as well as the environmental consequences associated with it.
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Kitchen waste contain easily degradable an organic biomolecules substances as feedstock for aerobic bio-reactor which works as aerobic digester system to produce highly simple organic and inorganic matters containing biomass as biofertilizers. To create an excellent biomass used as biofertilizers source which will be more valuable and an effective, eco-friendly, cut down on landfill waste, generates a high-quality biomass and reduces CH4, CO2 emissions & controlled global warming effect. Therefore these bio-fertilizers contain beneficial & active bacterial communities which involved in the regulation of soil properties on the basis of their biological activity. In the presence of oxygen, aerobic microbes play a major role in the degradation of complex organic materials into mainly to simple biomass & CO2 production. Aerobic treatment has favourable effects like removal of higher organic concentration, various pathogenic bacteria removal and also produces a stable biomass. The bio-digester requires addition of sodium hydroxide (NaOH) to maintain the alkalinity and pH to 7. For this reactor we have prepared an excellent bacterial community which applied into mixture of kitchen waste slurry along with other biowaste in aerobic bioreactor for biomass as humus production in large quantity and therefore, may be controlled of environmental pollution. A combination of these mixed an excellent bacterial community is used for biomass production at different temperature in laboratory.
Present day world is giving preference to organic produce over inorganic because of their awareness about the hazards of chemical produces. However, a limited supply of organic produce in the market is creating a huge gap among the costs of these produces. Major portion of organic produce is based on application of compost instead of applying microbial inoculants into the field. Previous studies reveal the benefits of compost application over chemical fertilizer in terms of quality produce and soil nourishment. Therefore, there is a need for better understanding of composting process so that the supply of organic produce can reaches upto the demand. In this review we are comparing two different types of composting process i.e. aerobic and anaerobic composting. A comparative analysis of these two types of composting can reveal the advantage of one over other and their limitations under natural/environmental conditions. Therefore, this review will be very useful in better understanding towards composting process.
The present study aimed to investigate microbial communities in seven Indian composts and their potential for biocontrol of Fusarium oxysporum f. sp. lycopersici. In addition, identification of bioactive substances in disease suppressive composts was also attempted. Composts were chosen based on disease suppressiveness and subjected to molecular microbial analyses. Total genomic DNA from the composts was extracted and amplified with polymerase chain reaction using primers targeting the 18S rRNA and 16S rRNA genes of fungi and bacteria, respectively. Denaturing gradient gel electrophoresis (DGGE) fingerprinting and DNA sequencing were used to identify the fungal and bacterial targets. Phylogenetic analysis of the fungal 18S rRNA ITS gene sequences showed that phylum Ascomycota was dominant in all composts, while in the bacterial 16S rRNA gene sequences, the phylum Proteobacteria was dominant. Some fungi in disease suppressive composts grouped phylogenetically close to F. oxysporum. Bacterial sequences with close similarity (>95% identity) with Actinobacterium showed a strong presence only in disease suppressive composts. Disease suppressive composts formed a separate group in the cluster analysis of 18S rRNA ITS and 16S rRNA gene sequences. Gas chromatography-time of flight-mass spectrometry was performed with compost extracts to determine if bioactive substances were present in disease suppressive composts. The analysis of compost organic matter showed a negative association of disease suppressiveness with phloroglucinol, sitosterol, and monoenoic fatty acid, while cholesterol and certain organic acids were positively associated with suppressiveness.
The aim of this study was to uncover ways to mitigate greenhouse gas (GHG) emissions and reduce energy consumption during the composting process. We assessed the effects of different aeration rates (0, 0.18, 0.36, and 0.54L/(kg dry matter (dm)·min)) and methods (continuous and intermittent) on GHG emissions. Pig feces and corn stalks were mixed at a ratio of 7:1. The composting process lasted for 10weeks, and the compost was turned approximately every 2weeks. Results showed that both aeration rate and method significantly affected GHG emissions. Higher aeration rates increased NH3 and N2O losses, but reduced CH4 emissions. The exception is that the CH4 emission of the passive aeration treatment was lower than that of the low aeration rate treatment. Without forced aeration, the CH4 diffusion rates in the center of the piles were very low and part of the CH4 was oxidized in the surface layer. Intermittent aeration reduced NH3 and CH4 losses, but significantly increased N2O production during the maturing periods. Intermittent aeration increased the nitrification/denitrification alternation and thus enhanced the N2O production. Forced aeration treatments had higher GHG emission rates than the passive aeration treatment. Forced aeration accelerated the maturing process, but could not improve the quality of the end product. Compared with continuous aeration, intermittent aeration could increase the O2 supply efficiency and reduced the total GHG emission by 17.8%, and this reduction increased to 47.4% when composting was ended after 36days. Copyright © 2015. Published by Elsevier B.V.
Gaseous emission (N2O, CH4 and NH3) from composting can be an important source of anthropogenic greenhouse gas and air pollution. A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio, aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system. The results showed that about 23.9% to 45.6% of total organic carbon (TOC) was lost in the form of CO2 and 0.8% to 7.5% of TOC emitted as CH4. Most of the nitrogen was lost in the form of NH3, which account for 9.6% to 32.4% of initial nitrogen. N2O was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it. Statistic analysis showed that the aeration rate is the most important factor which could affect the NH3 (p = 0.0189), CH4 (p = 0.0113) and N2O (p = 0.0493) emissions significantly. Higher aeration rates reduce the CH4 emission but increase the NH3 and N2O losses. C/N ratio could affect the NH3 (p = 0.0442) and CH4 (p = 0.0246) emissions significantly, but not the N2O. Lower C/N ratio caused higher NH3 and CH4 emissions. The initial moisture content can not influence the gaseous emission significantly. Most treatments were matured after 37 days, except a trial with high moisture content and a low C/N ratio.
Composting: Phases and Factors Responsible for Efficient and Improved Composting
  • A L Meena
  • M Karwal
  • D Dutta
  • R P Mishra
Meena, A. L., Karwal, M., Dutta, D. & Mishra, R.P. (2021). Composting: Phases and Factors Responsible for Efficient and Improved Composting. Agriculture and Food: e-Newsletter. 3(1): 85-90.