Synergistic effect of biochar amendment in milk processing industry sludge and cattle dung during the vermiremediation

The effective and sustainable management of fast growing and large quantities of industrial waste is a serious issue. The purpose of the present study was to assess the synergistic effect of biochar (BC) amended in milk processing industry sludge (MS) mixed with cattle dung (CD) in different ratios through vermiremediation. The MS25 and MS25BC10 (25:75 + 10 % BC) showed the least mortality and greatest earthworm growth and devel-opment. The final product from all feed mixtures recorded a decrease in pH, total organic carbon and C/N ratio. Other parameters viz., electrical conductivity, total available phosphorus, total Kjeldahl nitrogen, total sodium, total potassium and ash content was observed to be increased after vermicomposting. Significantly lower heavy metal content was found in all biochar amended feed mixtures than in mixtures without biochar. The germi-nation index of Trigonella foenum-graecum showed a value ranging from 89.14 to 131.46 % for mixtures without BC and 115.18-153.47 % for biochar amended mixtures.

Automated summary

The present study assessed the synergistic effect of biochar (BC) amended in milk processing industry sludge (MS) mixed with cattle dung (CD) through vermiremediation. The MS25 and MS25BC10 (25:75 + 10% BC) showed the least mortality and greatest earthworm growth and development. The final product from all feed mixtures recorded a decrease in pH, total organic carbon and C/N ratio, while other parameters such as electrical conductivity and nutrient content increased after vermicomposting. The addition of biochar also resulted in significantly lower heavy metal content and improved germination index of Trigonella foenum-graecum.