Process and production enhancement through codigestion in biogas generation

Abstract

Pakistan is facing a major challenge in the domestic gas and energy sector, and its demand is continuously growing. It is imperative to produce more energy in the form of gaseous resources and electricity to reduce this energy crisis in the future. The current work is related to studying various factors that play a critical role in enhancing the process and production of biogas. The effect of codigestion, substrate size, temperature, pH, and catalyst addition are important parameters. Three batch processes are conducted for 21 days under mesophilic conditions, which is easier to achieve as compared with the thermophilic one. Codigestion of cow manure combined with food, poultry waste, and sewerage water showed some promising results compared with a single substrate (cow dung). This results in the production of biogas of about 120 L. The particle size is then reduced to 5 mm, which leads to an increase in the available surface area for microbial attack and hence increases and enhances further the process and production of biogas. However, the addition of 250 g of silica gel increases production by up to 17%. The better value for the pH range for this batch was found in the range of 6.5–7.8. The codigestion would help in cost-effective and more efficient waste treatment. The digestate in all the batch processes comes out enriched in nitrogen that is used as an organic fertilizer.