Generation of Biogas Using Cow Dung With Organic Waste in the Presence of Iron Filings

In recent years, major issues such as demographic growth, food security, and exploitation of natural resources have raised worries worldwide. To handle these issues and the environment in an eco-friendly manner, a shift has been made from the mere exploitation of natural resources to their recovery and reuse. The production of organic waste is increasing dramatically. Anaerobic digestion (AD) with related biogas production is regarded as a substitute for waste management strategies such as landfilling and incineration of municipal solid waste (MSW). Biogas systems protect air, water, and soil by recycling organic waste into renewable energy and soil products while reducing greenhouse gas emissions. The present study aimed to establish a biogas system that involves co-digestion and iron filings. Specifically, it investigated the AD of vegetable waste combined with cow dung and Jatropha seed cake with iron filings. The experiment was conducted over ۶۰ days by four digesters (S۱, S۲, S۳, and S۴) containing mixtures of cow dung and vegetable waste (S۱), cow dung and Jatropha seed cake (S۲), cow dung and vegetable waste with ۱۰ g of iron filings (S۳), and cow dung and Jatropha seed cake with ۱۰ g of iron filings (S۴). After ۶۰ days, the amount of biogas collected from the digesters S۱, S۲, S۳, and S۴ was ۱۷۲.۹ mL/gVS, ۲۰۵.۶۴ mL/gVS, ۱۸۶.۰۸۶ mL/gVS, and ۲۳۱.۲۵ mL/gVS, respectively. The sample mixture of digester S۴, which contained cow dung and Jatropha seed cake with iron filings, resulted in the maximum yield of biogas production due to the iron additive potential for accepting and donating electrons.