老化轮胎微塑料对剩余污泥厌氧发酵产酸的影响

Effect of Ageing Tire Microplastics on Acid-Production of Anaerobic Fermentation for Excess Sludge

轮胎微塑料(TMPs)是污水中微塑料的主要来源之一,经污水处理流程后富集于剩余污泥内部,其理化性质及迁移转化影响污泥处理处置。文中采用强酸模拟环境老化的方法,探究老化TMPs对污泥厌氧发酵产酸的影响。结果表明,老化TMPs对污泥厌氧发酵产酸和水解过程都存在明显抑制,TMPs浓度越高,抑制程度越强,高浓度[0.2 g/(g VSS)]老化组挥发酸产量、SCOD_(Cr)、蛋白质和多糖较对照组分别减少了21.5%、40.0%、21.5%和18.6%。老化TMPs能抑制蛋白酶、α-葡萄糖苷酶和乙酸激酶等酶活性,导致功能微生物产生氧化应激反应或死亡。老化后TMPs颗粒粒径减小以及其浸出的有机物是发酵微生物产生氧化应激反应和污泥发酵系统效率降低的主要原因。上述研究结果对污泥厌氧发酵系统运行具有指导意义。

Tire microplastics(TMPs)are the main source of microplastics in the wastewater,which could be accumulated in the excess Sludge through wastewater treatment processes.The presence of TMPs would affect the disposal of sludge.This paper investigated the influence of aged TMPs on anaerobic fermentation of excess sludge.Strong acidic oxidant was applied to perform the ageing experiment.The results showed that the aged TMPs inhibited both hydrolysis and acidogenesis processes,which resulted from high TMPs concentration.Compared with the control group,the volatile fatty acid,SCOD_(Cr),protein and polysaccharide contents under high concentration[0.2 g/(g VSS)]were reduced by 21.5%,40.0%,21.5%and 18.6%,respectively.In fact,the aged TMPs could restrain the activities of protease,α-glucosidase and acetate kinase,which led to either oxidative stress or cell death regarding the functional microorganisms.The reduction of particle size and the solubilization of toxic organic matter caused by the ageing process important for the stable operation of anaerobic fermentation system.