WATER INDUSTRY: WATER-ENERGY-HEALTH NEXUS Temporal variation in bacterial and methanogenic communities of three full-scale anaerobic digesters treating swine wastewater Gyuseong Han 1 & Seung Gu Shin 2 & Kyungjin Cho 3 & Joonyeob Lee 1 & Woong Kim 4 & Seokhwan Hwang 1 Received: 22 June 2017 / Accepted: 19 December 2017 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract To investigate the effects of temporal variations of process parameters on microbial community structures in the two types of full- scale anaerobic digester treating swine wastewater, three full-scale anaerobic digesters were monitored. An anaerobic filter (AF)- type digester located in Gong-Ju (GJ) showed the highest COD removal among three digesters and maintained stable efficiency. A digester in Hong-Seong (HS) was of the same type as it GJ and showed improved efficiency over the sampling period. A continuously stirred tank reactor (CSTR)-type digester in Soon-Cheon (SC) showed decreasing efficiency due to a high residual concentration of VFAs and NH 4 + . These process efficiencies were closely correlated to the Simpson indices of the methanogenic communities. Genera Bacillus, Methanosaeta, and Methanospirillum that have filamentous morphology were dominant in both AF-type digesters, but genera Acholeplasma, Methanosarcina, and Methanoculleus that have spherical or coccoid morphology were dominantly abundant in the CSTR-type digester. Correlation between populations suggests a possible syntrophic relation- ship between genera Desulfobulbus and Methanosaeta in digesters GJ and HS. Keywords Full-scale, swine wastewater . Digester type . Anaerobic digestion . Microbial community . Multivariate analysis Introduction Swine wastewater (SWW) is a high-strength liquid organic waste that has a chemical oxygen demand (COD) of 50– 150 g/L. In South Korea, more than 30 million tons of SWW were produced in 2012 (MoE 2013). Release of SWW onto the ground or into groundwater causes serious environmental damage. Anaerobic digestion (AD) reduces SWW to a small quantity of innocuous digested sludge solids and generates combustible gas simultaneously, and is there- fore a promising treatment technology to treat SWW. Furthermore, owing to its easy biodegradability and high energy-production potential, SWW is more attractive than low-strength organics as a feedstock for the AD process (Kim et al. 2013). Therefore, a plan to construct full-scale digesters for SWW treatment has been instituted in South Korea; 13 full-scale anaerobic livestock wastewater treatment plants are currently operating. AD is a series of biochemical processes in which a micro- bial consortium of bacterial and archaeal species decomposes complex organic matter to CH 4 and CO 2 in the absence of O 2 in four main steps: hydrolysis, acidogenesis, acetogenesis, and methanogenesis. Despite the presence of distinct steps, the whole AD process involves complex symbiotic relationships Responsible editor: Gerald Thouand Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11356-017-1103-y) contains supplementary material, which is available to authorized users. * Woong Kim elshine@knu.ac.kr * Seokhwan Hwang shwang@postech.ac.kr 1 School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea 2 Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongnam National University of Science and Technology, Jinju, South Korea 3 Center for Water Resource Cycle Research, Korea Institute of Science and Technology, 39-1, Hawolgok-Dong, Seongbuk-Gu, Seoul 136-791, Republic of Korea 4 Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea Environmental Science and Pollution Research https://doi.org/10.1007/s11356-017-1103-y