Determination of the Ingredient of Organic Fraction of Municipal Solid Waste in Karaj and Its Impacts on the Potential of Biogas Production

Anaerobic digestion in order to produce biogas is a proven method for producing renewable energy from municipal solid waste. In this research, organic fractions of municipal solid waste compounds were determined in Karaj metropolitan area. The organic waste components were monitored in five categories of fruits, fat and protein, starches, vegetables, and cellulose wastes in the winter and summer seasons. Then, a sample representing the average amount of waste components was synthesized and biomethane yield, digestibility indicators and kinetic modeling parameters of biogas production were investigated in batch tests at mesophilic temperature at two concentrations of 8 and 15 TS%. The most part in the organic fraction was fruit and vegetable waste with a total of 62.9% and 70.6% in winter and summer, respectively. The biomethane yield and methane content at 8% and 15% TS had significant difference with 385.2 and 289.2 L/kg VS and of 66.8 and 58.8%, respectively, but there was no significant difference for VS removal with 87.99% and 84.72%. As a result, for source separated MSW, anaerobic digestion at the lower TSs has better results than dry. Continuous anaerobic digestion at 30 day hydraulic retention time is more effective for specific biomethane production and high volumetric biogas production under stable conditions.