Studies on Variations in Physico-Chemical and Biological Characteristics at Different Maturity Stages of Municipal Solid Waste Compost

The present study was under-taken to assess the changes occurring during the decomposition of municipal solid waste, through the estimation of some typical physico-chemical, biological characteristics and heavy metal concentrations. Changes in the composition characteristics of the compost over-time, included increased electrical conductivity, bulk density, water holding capacity and total soluble solids etc, during the decomposition process, where as the moisture content got reduced towards the end of composting (with final moisture content being around 29%). The changes in these characteristics appeared to reflect the microbial activity and biomass present. The successive levels of composting process, pathogenic bacterial populations decreased, physico-chemical analysis of compost from the point of view moisture content, pH, chloride, organic matter, calcium, magnesium, total phosphorus, total nitrogen, C/N ratio, sodium and potassium agreed with recommended standards and higher heavy metals concentrations was detected at all the decomposition stages of composting and were found to be within the permissible limits of Ohai-EPA standards. From the results, it can be concluded that, windrow composting could produce acceptable quality of compost, which can be used as fertilizer or soil amendment.