造纸废水中二甲苯对微生物活性的影响研究

Influence of xylene in papermaking wastewater on microbial activity

在缺氧和好氧条件下,通过对微生物的脱氢酶活性、VFA浓度、耗氧速率的研究来反映二甲苯对微生物的影响。当二甲苯的质量浓度低于40mg/L时,其对微生物脱氢酶活性的抑制率低于25%,为轻度抑制;而当大于80mg/L时,在缺氧条件下其对脱氢酶活性的抑制在第1天为中度抑制,之后转为轻度抑制;而在好氧条件下,抑制率一直大于25%,为中度抑制;水解酸化反应主要发生在第1天;好氧条件相比于缺氧条件6d后出水COD浓度更低;二甲苯对微生物耗氧速率的影响在第2天时达到较大,对照样和受试样耗氧速率之差达到44mg[O2]/(h·g[VSS]),但随着二甲苯的降解,其影响逐渐减小。

The influence of xylene on microbial activity under anoxic and aerobic condition were studied through the aspects of dehydrogenase activity, VFA concentration and oxygen consumption rate. When the mass concentration of xylene was lower than 40 mg/L, the inhibition rate of microbial dehydrogenase activity was lower than 25%, mild inhibition; when the mass concentration of xylene was above 80 mg/L, the inhibition of the dehydrogenase activity under anoxic condition was moderate inhibition at the first day, and then turned to mild inhibition in the following days; while under aerobic condition, the inhibition rate was always above 25%, moderate inhibition. Hydrolysis acidification reaction mainly occurred in the 1st day, and the effluent COD concentration under aerobic condition was lower than that under anoxic condition after 6 days of reaction; the influence of xylene on oxygen consumption rate reached the highest in the 2nd day, and the difference of microbial oxygen consumption rate between blank sample and testing sample were 44 mg [O2]/（h·g [VSS]）, however, the influence gradually decreased with the degradation of xylene.