Author(s): Rahat Niyazi1* and Sadhana Chaurasia2
Vermicomposting is commonly used for the management of organic wastes. A study was conducted to evaluate the efficiency of an exotic and epigeic earthworm species (Eisenia foetida) for stabilization of fly ash amended with pressmud. The growth and reproduction of E. fetida was also monitored in a range of different feed mixtures for 60 days 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, TAP and TK was recorded in final vermicompost. The heavy metals content in the vermicomposts was lower than initial feed mixtures. Vermicomposted samples showed 35-50% reduction of heavy metals in 40-60% FA. The growth rate and cocoon production was maximum in 100% PM. Metal analysis of E. foetida revealed considerable bioaccumulation of heavy metals in their body. Performance of feed mixture with 40-60% FA was better than the other feed mixtures. The results indicated that fly ash could be converted into good quality manure by vermicomposting if mixed in an appropriate ratio (40-60%) with pressmud.