Survey on solid wastes management by composting: Optimization of key process parameters for biofertilizer synthesis from agro wastes using response surface methodology (RSM)

Abstract

The optimization of key process parameters for the transformation of agro wastes into biofertilizer has been demonstrated using response surface methodology (RSM). Biofertilizer was produced by composting using 120 L capacity drum made of polyethylene as the composter. Composting time (X1), dosage ratio (X2) and moisture content (X3) were the independent factors while percentage nitrogen, phosphorus and potassium (N.P.K) were the response factors. The outcomes exhibited that composting time, dosage ratio and moisture content all significantly affects the mineralization of N.P.K at probability value of 0.0001. The coefficients of determination also called regression coefficients of 98.60%, 99.79% and 97.80% for nitrogen, phosphorus and potassium observed between the predicted and the real value are obvious that the developed regression models can fit the experimental data well. It was seen from the optimization studies that the pinnacle value of N.P.K from the ideal conditions are 9.62%, 8.97% and 5.62. Characterization of the composite uncovered that biofertilizer produced has a high potential for commercial application on agricultural land. It can be concluded that combination of sawdust, sewage sludge and vegetable waste is a good mixture for biofertilizer synthesis. Also, the nutrients release by the compost materials during the process of composting may be maximized when process conditions are circumspectly managed within the reported optimal value. Keywords: Optimization, Composting, Sawdust, Sewage sludge, Vegetable wastes, Response surface methodology