Main content area

Influence of arsanilic acid, Cu2+, PO43– and their interaction on anaerobic digestion of pig manure

He, Ping, Wu, Guangxue, Tang, Rui, Ji, Peilun, Yuan, Shoujun, Wang, Wei, Hu, Zhenhu
Frontiers of environmental science & engineering 2018 v.12 no.2 pp. 9
anaerobic digesters, anaerobic digestion, arsanilic acid, arsenicals, copper, feces, feed additives, methane production, phosphates, pig manure, swine, toxicity, urine
Arsanilic acid (ASA), copper ion (Cu²⁺) and phosphate (PO₄³–) are widely used as feed additives for pigs. Most of these three supplemented feed additives were excreted in feces and urine. Anaerobic digestion is often used for the management of pig manure. However, the interaction of ASAwith Cu²⁺ or PO₄³– on anaerobic digestion is still not clear. In this study, the influence of ASA, Cu²⁺, PO₄³– and their interaction on anaerobic digestion of pig manure and the possible mechanisms were investigated. The initial concentrations of ASA, Cu²⁺ and PO₄³– were 0.46 mM, 2 mM and 2 mM in the anaerobic digester, respectively. The methanogenesis was severely inhibited in the assays with only ASA addition, only Cu²⁺ addition and ASA + PO₄³– addition with the inhibition index of 97.8%, 46.6% and 82.6%, respectively, but the methanogenesis inhibition in the assay with ASA + Cu²⁺ addition was mitigated with the inhibition index of 39.4%. PO₄³– had no obvious impacts on the degradation of ASA. However, Cu²⁺ addition inhibited the degradation of ASA, and mitigated the methanogenesis inhibition. The existence of ASA would inhibit methanogenesis and generate more toxic inorganic arsenic compounds during anaerobic digestion, implying the limitation of anaerobic digestion for ASA- contaminated animal manure. However, the co-existence of ASA and Cu²⁺ could mitigate the inhibition. These results could provide useful information for the management of anaerobic digestion of pig manure containing ASA and Cu²⁺.