Qualitative assessment of compost engendered from municipal solid waste and green waste by indexing method.

Abstract

The present study aims at quantification of the quality of three varieties of composts made from municipal solid waste, green waste and combined waste by critically evaluating their physicochemical attributes, effect on soil fertility and metal pollution risk. Each waste type was treated with effective micro-organisms to compare the compost quality using Quality Control Indices. The effect of microbial consortia on the wastes was prominent resulting in decreased pH levels and increased electrical conductivity. C/N ratio ranged between 14-24 for waste composts without microbial treatment, and 8-11 for microbial treated wastes. The fertility parameter was observed to be more in microbial treated waste composts. Also, heavy metals concentration in waste compost without effective microbial treatment was higher than the types given EM. Based on the fertility and clean indices, the treated and untreated municipal solid waste and combined waste compost belonged to class RU-1 and class D, respectively. Moreover, compost prepared from treated and untreated green waste belonged to classes B and C respectively. In general, the prepared CW and GW composts have medium to high fertilizing potential and are fit for domestic as well as commercial use. However, MSW compost is not fit for agricultural purposes as it didn t improve soil fertility to a greater extent but can be used as a soil conditioner in limited quantity as it can cause metal toxicity. For this reason, proper segregation of inputs at the start of a composting process is necessary to improve its quality before being put to agricultural use as any unbalanced or unchecked content of mixed waste will affect the overall compost quality.