Kinetic study and optimization of total solids for anaerobic digestion of kitchen waste: Bangladesh perspective

Abstract

Kitchen waste from hotels and homes is one of the major problems for urban and rural environment and could be one of the best sources of renewable energy by producing biogas through anaerobic digestion. A research work was undertaken to assess the methane potential of kitchen waste at different total solids (TS) content. Kitchen wastes such as spoiled rice, brinjal, potato, papaya, tomato, fish and poultry parts etc., which are easily decomposed, were selected for this study. Batch experiments were set up under ambient temperature. Kitchen waste was added to the batch digester at different TS content (5, 7, 10, 12 and 15%) and sealed for 146 days until the gas production stopped. Substrate characteristics were analyzed before and after the anaerobic digestion. The highest methane yield was 78.12 L/kg VS at 15% TS content followed by 12, 10, 7 and 5%. Different kinetic parameters were determined using a logistic model and the model showed a good fit with the experimental results. After modelling using Minitab®, the optimum TS content for kitchen waste was found to be 14.90%. HIGHLIGHTS Performance of anaerobic digestion at different solid concentrations of kitchen waste were investigated.; The total solids content was optimized to maximize yield.; Significant variation in methane yield was observed at different total solids.; The optimum total solids was found to be 14.90% with methane yield of 78.23 L/kg VS.;

Keywords

• anaerobic digestion
• biogas
• kitchen waste
• optimization
• total solids