Enhanced anaerobic treatment of Polybutadiene adipate terephthalate wastewater in up-flow anaerobic sludge blanket by pre-acidification: Pollutants degradation and microbial succession

Polybutadiene adipate terephthalate has become an emerging alternative to traditional plastic due to its good biodegradability. However, the treatment of PBAT wastewater, which contains high concentrations of toxic pollutants, is still challenging. Anaerobic digestion is a promising technology for PBAT wastewater treatment. In this study, the biochemical methane potential (BMP) of wastewater was analyzed, the effects of hydrolytic acidification pretreatment on anaerobic digestion under low pH conditions were investigated. The results indicated that the average COD removal rate of the two-phase anaerobic group was 62.2%, which was 1.3 times higher than that of the single-stage anaerobic process. After hydrolysis acidification treatment at pH value of 3.8-4.2, the contents of cyclopentanone, 1,4-butanediol, n-butanol, and tetrahydrofuran in the wastewater were reduced by 18.8%, 38.0%, 12.9%, and 0.6%, respectively; the methane conversion rate of the methanogenic phase in the steady stage was 159.4 ml CH 4 /gCOD, which was 38.0% higher than that of the single-stage anaerobic process. According to the 16SrRNA analysis, hydrolytic acidification of wastewater promoted the enrichment of hydrogen-producing acetogens and increased the relative abundance of Methanosarcina in the methanogenic phase. Therefore, pre-acidification at low pH conditions can effectively remove toxic pollutants from PBAT wastewater and enhance the methane conversion rate. • The biochemical methane potential of PBAT wastewater was analyzed. • Anaerobic methanogenes can be inhibited by tetrahydrofuran and cyclopentanone. • The two-phase anaerobic process provides better treatment for PBAT wastewater. • Hydrolytic acidification under low pH of PBAT wastewater reduces the treatment difficulty. • Hydrolytic acidification promotes the enrichment of Methanosarcina in UASB.