OPTIMIZATION MODEL OF BIOGAS PRODUCTION EFFICIENCY FROM DIFFERENT SOURCES OF WASTE BY ANAEROBIC DIGESTION

Abstract

This research paper focuses on the optimization modeling of biogas production efficiency from various sources of waste using anaerobic digestion. The study was conducted in a controlled laboratory environment employing mini-biodigesters with a capacity of 120 liters. Four different feedstocks—sewage, pig waste, poultry waste, and homemade waste (a mixture of watermelon and pineapple)—were used as substrates to feed the biodigesters individually and in various combinations. The experimental results over a 14-day maximum production period indicated average daily biogas production rates of 0.0329, 0.0372, 0.0354, 0.0296, 0.0362, 0.0384, and 0.0410 liters per day for the substrates: sewage waste (X1), pig waste (X2), poultry waste (X3), homemade waste (X4), the combination of sewage and homemade waste (X1+X4), the combination of sewage, pig, and poultry waste (X1+X2+X3), and the combination of all four substrates (X1+X2+X3+X4), respectively. The methane content in the biogas produced from these substrates was found to be 54.8%, 58.7%, 56.6%, 51.7%, 68.2%, 65.5%, and 69.3%, respectively. To optimize biogas production, a mathematical model was formulated with the variables X1, X2, X3, and X4 subjected to time constraints. The Simplex Method was employed to solve the model, resulting in an objective function value of 12.22286. The optimal values of the variables were X1 = 0, X2 = 4.285714, X3 = 1.428571, and X4 = 1.78E-16, indicating the most efficient combination of feedstocks for biogas production. This study provides significant insights into the efficiency of biogas production from different waste sources and their combinations, contributing to the optimization of anaerobic digestion processes for sustainable energy production.

Keywords:  Agricultural wastes; Biogas production; Homemade wastes; Optimization Model; Sewage wastes Digestion.