Long-term influence of trace element deficiency on anaerobic mono-digestion of chicken manure

• Published in: Journal of environmental management 2018-10, Vol.223, p.743-748
• Main Authors: Molaey, Rahim, Bayrakdar, Alper, Çalli, Bariş
• Format: Article
• Language: English
• Subjects: Ammonia; Methane; Methanoculleus; Selenium; Syntrophic acetate oxidation
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2018.06.090

Recent findings showed that some trace elements essential for anaerobic digestion might be deficient in chicken (laying hens) manure. In this study, the long-term influence of trace element deficiency on anaerobic mono-digestion of chicken manure was investigated. Three bench-scale anaerobic reactors were operated with or without trace element supplementation. As trace element, only Se or a mix containing Co, Mo, Ni, Se, and W was added to the reactors. The results revealed that in anaerobic digestion of chicken manure at total ammonium nitrogen concentrations over 6000 mg L−1, Se supplementation was critical but not sufficient alone for long-term stable CH4 production. Addition of a mix consisting of Co, Mo, Ni, Se and W resulted in a more stable digestion performance. Daily trace element mix supplementation promoted the hydrogenotrophic Methanoculleus bourgensis, which is an ammonia tolerant methanogen. The decrease in the relative abundance of Methanoculleus detected after termination of trace element addition and resulted in accumulation of acetate and propionate that followed by a significant decrease in CH4 production. [Display omitted] •In long-run, sole Se addition is not sufficient for efficient chicken manure digestion.•Main route of CH4 production was syntrophic hydrogenotrophic pathway at high ammonium concentrations.•Hydrogenotrophic Methanoculleus was stimulated by trace element mix supplementation.•Termination of trace element mix addition caused accumulation of acetate and propionate.