In order to investigate the effects of different adsorbents on carbon source concentration and membrane separation in the coagulation adsorption microfiltration process, this study used polyaluminum chloride (PACL) as a coagulant, and compared three types of adsorbents: powdered activated carbon (PAC), biochar (BC), and magnetic biochar (Fe-BC). The concentration efficiency, membrane fouling characteristics, methane production potential, and microbial community analysis of the concentrate were revealed. Content of COD, protein, and total phosphorus in the concentrate was significantly increased by the addition of adsorbents. The optimal concentration efficiency of the PAC group was 81.8%, and the protein content was about 2.4 times that of the control group. However, the enrichment effect of polysaccharides and total nitrogen was not significant. The membrane fouling of the BC group concentrate was found to be lower. A membrane resistance of 3.31 × 108m-1 caused by the concentrate was lower than that of the AC group (4.61 × 108m-1) and the Fe BC group (4.13 × 108m-1). In addition, the relative abundance of Proteobacteria, which are prone to membrane fouling, in the BC group concentrate was lower. The higher methane production potential of the BC group was due to the higher abundance of Bacteroidota, which participated in EPS and floc formation in the concentrate. The high abundance of Firmicutes involved in the hydrolysis and acidification process in the Fe BC concentrated solution provided favorable conditions for improving the methane production rate. © 2024 Chinese Society for Environmental Sciences. All rights reserved.