Quality assessment of compost and vermicompost derived from pressmud amended fly ash

Abstract

Fly ash is produced in large quantities in thermal power plants and the storage and/or spreading of this waste on land may cause contamination of the atmosphere, soil and water. The aim of the present study was to evaluate the effectiveness of the composting and vermicomposting for reducing the polluting potential and for stabilizing fly ash in the short-term. For this, the physico-chemical as well as the pathogenic characteristics of the resulting products before and after the active phase of composting and vermicomposting were analyzed. The growth and reproduction of Eisenia foetida was also monitored in a range of different feed mixtures after vermicomposting in laboratory under controlled experimental conditions. In all the feed mixtures, a decrease in temperature, pH, TOC, C: N ratio and faecal coliforms, but increase in EC, TKN and TAP was recorded in final composts and vermicomposts. The TK content was increased in vermicomposts but no significant change was found in composts. In vermicomposting the growth rate and cocoon production was maximum in 100% PM. The results indicated that vermicomposting was more effective in terms of stabilizing the PM amended FA and thereby producing improved substrates for agricultural use.