Strategic Action Plan - International Environmental Technology Centre

Strategic Action Plan Report
2) Moisture content
The composting mass should have certain minimum moisture content in it for the organisms to survive. The
optimum moisture content is known to be between 50 to 60 %.
3) Temperature
Under properly controlled conditions temperature rises beyond 70°C in aerobic composting. This increased
temperature results in increased rate of biological activity and hence results in faster stabilization of the
material. The temperature range of 50° to 60°C is optimum for nitrification and cellulose destruction.
4) C/N Ratio
The organisms involved in stabilization of organic matter utilize about 30 parts of carbon for each part of
nitrogen and hence an initial C/N ratio of 30 is most favorable for composting. Whenever the C/N ratio is
less than the optimum, carbon source such as straw, saw dust, paper are added while if ratio is to high, the
sewage sludge, slaughter house waste, blood etc. are added as a source of nitrogen.
Table 5.1 enlists the significant factors that affect the proper and effective functioning of the composting
process.
S.
N.
Table 5.1: Important Factors Required For Aerobic Composting Process
Item
1 Particle Size Should be between 25-50mm
2 Seeding and
Mixing
3 Mixing and
Turning
Comment
Composting time can be reduced by seeding with partially decomposed
solid waste of about 1-5% by weight. Sewage sludge can be added to
prepared solid waste.
To prevent, caking and air channeling material in process being
composted should mixed for uniform distribution of nutrients and
microorganisms and turned regularly for maintaining the aerobic activity.
4 Air Requirement Air with at least 50% of initial oxygen concentration remaining should
reach all parts of composting material for optimum results.
5 Moisture
Content
Moisture content should be between 50 to 60% during the composting
process and optimum being 55%.
6 Temperature The optimum temperature for biological stabilization is 45 to 55 0 C. For
best results it has been found that temperature should be maintained 55 0 -
60 0 C for remainder of the active composting period. If temperature rises
above 65 0 C the biological activity can be reduced.
7 C/N Ratio Initial C/N ratio (by weight) should be 35-50 for optimum results. At low
ratios nitrogen is in excess and will be given as ammonia. Biological
activity is also impeded at lower ratios. At higher ratios nitrogen may be
limiting nutrient. After composting C/N ratios for most of the MSW will
ISWM Plan for Pune 93