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. (C) 2012 Elsevier B.V. All rights reserved.