State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering , Tongji University , Shanghai 200092 , PR China.
Shanghai Institute of Pollution Control and Ecological Security , Shanghai 200092 , P.R. China.
Environ Sci Technol. 2019 Mar 5;53(5):2509-2517. doi: 10.1021/acs.est.8b07069. Epub 2019 Feb 21.
The retention of polyvinyl chloride (PVC) microplastics in sewage sludge during wastewater treatment raises concerns. However, the effects of PVC microplastics on methane production from anaerobic digestion of waste activated sludge (WAS) have never been documented. In this work, the effects of PVC microplastics (1 mm, 10-60 particles/g TS) on anaerobic methane production from WAS were investigated. The presence of 10 particles/g TS of PVC microplastics significantly ( P = 0.041) increased methane production by 5.9 ± 0.1%, but higher levels of PVC microplastics (i.e., 20, 40, and 60 particles/g TS) inhibited methane production to 90.6 ± 0.3%, 80.5 ± 0.1%, and 75.8 ± 0.2% of the control, respectively. Model-based analysis indicated that PVC microplastics at >20 particles/g TS decreased both methane potential (B) and hydrolysis coefficient (k) of WAS. The mechanistic studies showed that bisphenol A (BPA) leaching from PVC microplastics was the primary reason for the decreased methane production, causing significant ( P = 0.037, 0.01, 0.004) inhibitory effects on the hydrolysis-acidification process. The long-term effects of PVC microplastics revealed that the microbial community was shifted in the direction against hydrolysis-acidification and methanation. In conclusion, PVC microplastic caused negative effects on WAS anaerobic digestion through leaching the toxic BPA.
聚氯乙烯（PVC）微塑料在废水处理过程中在污水污泥中的保留引起了关注。然而，PVC 微塑料对废活性污泥（WAS）厌氧消化产甲烷的影响从未有过记录。在这项工作中，研究了 PVC 微塑料（1mm，10-60 个/克 TS）对 WAS 厌氧甲烷生产的影响。10 个/克 TS 的 PVC 微塑料的存在显著（P=0.041）增加了 5.9±0.1%的甲烷产量，但更高水平的 PVC 微塑料（即 20、40 和 60 个/克 TS）分别抑制了 90.6±0.3%、80.5±0.1%和 75.8±0.2%的甲烷产量。基于模型的分析表明，大于 20 个/克 TS 的 PVC 微塑料降低了 WAS 的甲烷潜能（B）和水解系数（k）。机理研究表明，从 PVC 微塑料浸出的双酚 A（BPA）是甲烷产量降低的主要原因，对水解酸化过程产生了显著的（P=0.037、0.01、0.004）抑制作用。PVC 微塑料的长期影响表明，微生物群落朝着不利于水解酸化和甲烷化的方向发生了变化。总之，通过浸出有毒的 BPA，PVC 微塑料对 WAS 厌氧消化产生了负面影响。
