Performance and microbial community analysis of anaerobic sludge digestion enhanced by in-situ microaeration. (August 2021)

• Record Type: Journal Article
• Authors: Zhou, Zhen; Ming, Qiang; An, Ying; Ruan, Danian; Chen, Guang; Wei, Haijuan; Wang, Mengyu; Wu, Zhichao
• Is Part Of: Journal of water process engineering. Volume 42(2021)
• Publication Date: 2021-08
• Subjects: Microaeration -- Anaerobic digestion -- Methane -- Enzymatic activity -- Microbial community; Water-supply engineering -- Periodicals; Saline water conversion -- Periodicals; Seawater -- Distillation -- Periodicals; Sanitary engineering -- Periodicals; Sewage -- Purification -- Periodicals; 627
• DOI: 10.1016/j.jwpe.2021.102171
• Languages: English
• ISSNs: 2214-7144

Abstract

Abstract: The effectiveness of in-situ microaeration was investigated with varied air dosages [0–25 mL/(L·d)] to enhance mesophilic anaerobic digestion (AD) of sludge in semi-continuous systems in terms of specific biogas production and volatile solids (VS) removal rate, focusing on performance evaluation, microbial community analysis, and underlying mechanisms. The optimal dosage of 12.5 mL/(L·d) increased specific biogas production by 15.8 ± 7.3% and enhanced VS removal by 18.3 ± 1.6%. In-situ microaeration stimulated activity of hydrolytic enzymes, enlarged sludge particle size, and improved sludge dewaterability. MiSeq sequencing analysis showed that dominant bacterial and archaeal communities were remarkably different between in-situ microaeration and obligate AD process. The presence of oxygen enriched relative abundances of Deltaproteobacteria, Anaerolineae, Clostridia, Synergistia and Caldilineae, enabling the acid-producing process to metabolize more types of substrates. Due to the selective enrichment, in-situ microaeration significantly enriched aceticlastic methanogens rather than hydrogenotrophic methanogens in the AD reactor. Analysis of coupling microaeration pretreatment and in-situ microaeration for anaerobic digestion indicated that excessive microaeration decreased VS removal rate and methane yield owing to substrates consumption by facultative bacteria. In-situ microaeration-based AD could be a promising process for sludge treatment and bioenergy recovery. Graphical abstract: Unlabelled Image Highlights: Effects of in-situ microaeration on anaerobic digestion (AD) of sludge were studied. Optimal microaeration dosage of 12.5 mL/(L·d) enhanced biogas production by 15.8%. Oxygen stimulated hydrolytic enzyme activity and improved sludge dewaterability. Microaeration enriched microbial species of Methanomicrobia and Methanosaeta . Energy balance showed proper in-situ microaeration was cost-effective to enhance AD.