Enhancing methane production by adding Fe³⁺ in mesophilic anaerobic digestion of cheese waste

¹ Department of Biosystems Engineering, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, Indonesia
² Politeknik Negeri Lampung, Bandar Lampung, Indonesia
³ School of Water, Energy and Environment, Cranfield University, Cranfield, Bedfordshire, UK

Abstract

The advancements in cheese production technology have resulted in increased waste generation, especially in the form of liquid byproducts left over after the milk clotting process. This research examines the possibility of using cheese waste to produce methane (CH₄) through mesophilic anaerobic digestion and investigates how adding iron (Fe) can improve CH₄. Field experiments were conducted to evaluate the effects of varying concentrations of cheese waste (0–33.33 g/L) and FeCl₃ (0–3.0 g/L) on CH₄ yield. Results revealed that the addition of 2 g/L FeCl₃ achieved the highest cumulative CH₄ yield and production rate, with increases of 68% and 65% over the control, respectively. The study also monitored pH levels and found that the best treatment maintained a near-neutral pH of 6.79 by day 50, which is important for sustaining effective microbial activity. This study highlights the potential of incorporating Fe supplementation to optimize CH₄ yields from cheese waste and other organic substrates, contributing to more sustainable and efficient renewable energy production.