Effect of salinity and pH on dark fermentation with thermophilic bacteria pretreated swine wastewater

• Published in: Journal of environmental management 2020-10, Vol.271, p.111023-111023, Article 111023
• Main Authors: Li, Xunzhou, Guo, Liang, Liu, Yue, Wang, Yi, She, Zonglian, Gao, Mengchun, Zhao, Yangguo
• Format: Article
• Language: English
• Subjects: Hydrogen production; Salinity; Soluble metabolites; Swine wastewater
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2020.111023

The utilization of swine wastewater is affected by salinity and pH owing to the extensive use with seawater instead of domestic water as swine farm flushing water in coastal city. Therefore, swine wastewater pretreated with thermophilic bacteria was used as fermentation substrate in this work, the effects of salinity and pH on dark fermentation under mesophilic condition were investigated. The research showed that 1.5% salinity and pH 6.0 were the optimal conditions for hydrogen production with swine wastewater. The activity of hydrogenogen was inhibited at 3.5% salinity and pH 5.0. Soluble organic matter in substrate was accumulated under high salinity and alkaline conditions. The utilization of carbohydrate during dark fermentation was up to 61.1% at 1.5% salinity and 51.5% at pH 9.0. Enhancing of salinity and pH had an advantage in accumulation of total soluble metabolites. Acetate was the main metabolite during dark fermentation, and 1.5% salinity contributed to the formation of butyrate. [Display omitted] •The optimal conditions for hydrogen production were 1.5% salinity and pH 6.0.•The nutrients changing could be influenced by salinity and pH.•Accumulated soluble metabolites of acetate and propionate were main metabolites.•1.5% salinity contributed to the formation of butyrate.