Co-composting of gelatin industry sludge combined with organic fraction of municipal solid waste and poultry waste employing zeolite mixed with enriched nitrifying bacterial consortium

This work illustrates the co-composting of gelatin industry sludge (GIS) combined with organic fraction of municipal solid waste (OFMSW) and poultry waste (PW) employing 10% zeolite mixed with enriched nitrifying bacteria consortium (ENBC). Five piles of GIS were prepared mixed with OFMSW and PW at 2:1:0.5, 4:1:0.5, 6:1:0.5 and 8:1:0.5 and without GIS 0:1:0.5 (dry weight basis) served as control, while 10% zeolite mixed with ENBC was inoculated in all piles and composted for 42 days. The Pile-4 with GIS, OFMSW and PW ratio 6:1:0.5 and 10% zeolite + ENBC were drastically reduced the nitrogen loss and enhance the mineralization rate as compare to other piles. The co-amendment of 6% GIS effectively buffered the pH between ∼7.5 to 8.0 and shortened the compost maturity period, while lower concentration of GIS was comparatively delayed the early decomposition. Therefore, our results suggested that suitability of 10% zeolite + ENBC with initial feedstock ratio 6:1:0.5 as the best formulation for the composting of GIS into value-added stable product.