Enhancing anaerobic digestion of chicken manure leachate: Effects of trace elements supplementation on methane production

Anaerobic digestion (AD) of Chicken manure (CM) often faces several obstacles such as high total ammonia nitrogen (TAN) concentration, inclusion of many hard-to-decompose litters as wood chips, and presence of inorganic soil particles. To address these obstacles, degradable fractions of CM were extracted by leaching and the chicken manure leachate (CML) obtained was used for AD. The effects of trace element (TE) supplementation in stimulating microbial activity and enhancing the AD process, under increasing organic loading rate (OLR) and TAN concentration, were investigated. The results showed that CML was successfully converted, reaching a stable methane yield of 288 mL g−1 VS when TAN was lower than 1.5 g L−1. Under higher OLR (0.85 gVS L−1 d−1) and TAN (2.64 g L−1), TEs supplementation gave 36.5% higher methane yield (p < 0.05). Overall, extracting leachate from CM in combination with TE supplementation was shown to be a promising strategy for CM treatment. © 2021 Elsevier Ltd