五氯酚在厌氧生物体系中的降解及反馈作用

Effects of PCP on anaerobic biodegradation

为探讨厌氧系统降解五氯酚(PCP)能力及PCP对厌氧系统的毒性影响,采用UASB反应器进行了PCP模拟污水连续流试验,考察了不同PCP浓度及负荷条件下系统对PCP和COD的降解去除规律,揭示了PCP对系统产酸相和产甲烷相影响状况.结果表明,在进水PCP含量从无到开始加入、PCP浓度提高以及PCP负荷提高3个冲击变化阶段,厌氧系统对PCP和COD的去除率均表现出先迅速降低后缓慢升高的变化趋势,运行稳定后PCP和COD的去除率分别达91.2%和83.5%以上.PCP对厌氧系统中微生物种群产生影响,使系统产酸菌由丁酸型菌群为主逐渐演替为丙酸型菌群为主,PCP对系统产甲烷菌活性产生明显抑制,甲烷产量由PCP加入前的12.1L/d降低至加入后的2.5L/d.

Pentachlorophenol （PCP） is a common wood preservative that effects bacteria used to biodegrade sewage water. To investigate an aerobic biodegradation system＇s ability to degrade PCP and evaluate the toxic effects of PCP on the system, an experiment that simulated a continuous-flow of PCP contaminated sewage water was carried out using an upflow anaerobic sludge blanket （UASB） reactor. The study revealed that the degradation rates of PCP and chemical oxygen demand OR 1,5-Cyclooctadiene （COD） and the influence of PCP on the acidogenic phase and the methane production phase were a function of PCP concentrations and loads. The results indicated that during the three stages of PCP addition （PCP introduction, PCP concentration increase, and PCP load increase）, the degradation rates of PCP and COD showed a trend of an initial quick drop followed by a slow rise. After the anaerobic degradation system stabilized, the degradation rates of PCP and COD reached 91.2% and 83.5%, respectively. PCP influenced the microorganic composition of the anaerobic system, gradually transforming the acidogenic bacteria from predominantly butyric acid bacteria to predominantly propionic acid bacteria. PCP also significantly inhibited the activity of methane producing bacteria. The volume of methane produced dropped from 12.1 L/d before the addition of PCP to 2.5 L/d afterwards.