微塑料对剩余污泥-废油脂共发酵产酸的影响

Effects of Microplastics on Short-chain Fatty Acid Production by Co-Fermentation of Waste Activated Sludge and Waste Cooking Oil

基于剩余污泥-废油脂碱性共发酵,考察聚乙烯微塑料对产短链脂肪酸(SCFA)的影响。实验结果表明,微塑料对发酵液中的SCFA浓度影响明显,但对SCFA的组成影响较小。微塑料在低赋存水平下抑制产酸,高水平时反而促进。微塑料10个/(g TS)时产酸量最低,SCFA浓度较对照低245.6 mg COD/L。微塑料200个/(g TS)时产酸量最高,最大SCFA浓度和酸产率较对照分别提升了24.7%和37.13 mg COD/(g VS)。微塑料高含量时多糖和蛋白质的水解酸化减弱,废油脂水解产物LCFA的降解得到加强。进一步的高通量测序结果显示,微塑料改变了发酵体系的微生物群落结构,高含量时反应器中存在较多氢自养反硝化菌(Pseudomonas,Alcaligene)代谢消耗发酵体系中的氢气,改善了LCFA的降解状况,提高了共发酵体系SCFA尤其是乙酸的积累。

Based on alkaline co-fermentation of waste activated sludge and waste cooking oil,the effect of polyethylene(PE)microplastics on the production of short chain fatty acids(SCFA)was studied.The results showed that the microplastics had an obvious effect on the production of SCFA,but had a little effect on the composition of SCFA.Microplastics inhibited acid production at low contents and promoted it at high contents.When the content of microplastics in fermentor was 10 particles/(g TS),the SCFA concentration was 245.6 mg COD/L lower than that of the control.Instead,when the content of microplastics reached 200 particles/(g TS),the concentration of SCFA and the yields of SCFA increased by 24.7%and 37.13 mg COD/(g VS)compared with the blank,respectively.In addition,high contents of microplastics were not favorable to the hydrolysis and acidification of carbohydrate and protein,but stimulated the degradation of LCFA.Further high-throughput sequencing results showed that the microbial community structure of the fermentation system varied because of the existence of microplastics,and the relative abundance of denitrifying bacteria(Pseudomonas and Alcaligene)in the reactor with 200 particles/(g TS)enriched.They metabolism consumed hydrogen improving the degradation of LCFA,thus SCFA yield,especially acetic acid,were enhanced.