The Role of Iron in Biogas Production: A Study Focused on Toxicity

Anaerobic digestion is used as an alternative waste treatment and for generating clean energy through the production of renewable biogas. Iron serves as an additive to improve biogas production by facilitating waste treatment; however, a high amount of iron can cause a toxic problem for microorganisms. This project aimed to determine the toxic effect of iron on biogas production from organic waste. This experiment was conducted in five 40 mL batch reactors, each containing a carbohydrate-rich substrate, with a pH of seven, and the expected volume for each reactor was 4.26 L of biogas per mole of sucrose. The reactors operated at 37°C at different concentrations of iron (III) sulfate in duplicate: 200 mg Fe2 (SO4)3 /L, 400 mg Fe2 (SO4)3 /L, 700 mg Fe2 (SO4)3 /L, and 1,000 mg Fe2 (SO4)3 /L. The results showed that the concentration producing a toxic effect on the microorganisms is 1,000 mg Fe2 (SO4)3 /L of Fe. This project concludes that the objective was met, and the benefits of using Fe in anaerobic digestion are attractive. However, it is important to limit its concentration within the framework of effective waste remediation and renewable energy production.