Vermistabilization of wastewater sludge from milk processing industry

This work illustrates the vermistabilization of milk processing industry wastewater sludge (MPIS) spiked with cow dung (CD) using earthworm Eisenia fetida. A total of four experimental vermibeds were established and changes in chemical parameters of waste material have been observed for 90 days. Vermistabilization caused significant reduction in pH, organic carbon and C:N ratio and substantial increase in total N, available P, exchangeable cations (K+ and Ca2+) and extractable trace elements (Fe, Mn and Zn). The waste mixture containing MPIS (60%) + CD (40%) showed the better mineralization rate as compared to others. The growth and cocoon production in E. fetida was also monitored in all experimental vermibeds. Also, E. fetida showed better growth and reproduction pattern in vermibeds with 40-60% MPIS. At high concentration MPIS caused significant mortality in worms. Results, thus suggested the suitability of vermicomposting for stabilization of noxious milk processing industry sludge.