【摘要】 为探究水力停留时间(HRT)对丙酸去除效能的影响及丙酸氧化菌群的响应,以丙酸为底物,升流式厌氧污泥床(UASB)的运行为基础,研究HRT缩短对UASB系统丙酸去除的影响,并通过聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)指纹分析技术,分析丙酸氧化菌群随HRT缩短的演替规律.结果表明,在保持进水COD 2 000 mg.L-1不变,HRT由10 h经由8、6 h缩短至4 h的过程中,每次HRT的缩短都会造成UASB系统中丙酸的短期积累.但经过一段时间的连续运行之后,UASB均能重新达到稳定运行状态,并保持较高的丙酸去除率.在此过程中,UASB中厌氧活性污泥的比CODpro去除率由HRT 10 h时的1.2 kg/(kg.d)逐渐提高到4 h时的1.7 kg/(kg.d).HRT的缩短使UASB系统中丙酸氧化菌群发生了明显的演替,以条带2～4为代表的丙酸氧化菌(Syntrophobacter fumaroxidans)随着HRT的缩短逐渐被强化,而条带5(S.sulfatireducens)逐渐减弱.丙酸氧化菌Pelotomaculum propionicicum(条带1和6)在整个运行过程中优势度保持相对稳定.HRT的缩短刺激了具有较高动力学特性的条带2～4(S.fumaroxidans)快速增殖,使其在活性污泥中的优势度不断提高,而该菌的强化使得UASB系统能够在有机负荷高达18 kg/(m3.d)条件下仍保持了94.1%的丙酸去除率.更多还原

【Abstract】 To investigate the effect of HRT on propionate degradation and propionate-oxidizing bacteria,an upflow anaerobic sludge blanket(UASB) containing propionate as sole carbon source was introduced.The propionate oxidation with decrease of HRT was evaluated and propionate-oxidizing bacteria shift was analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE).Under influent propionate 2 000 mg·L~-1 condition,the shortening of HRT from 10 h to 8 h,6 h,and 4 h would cause a transient accumulate in propionate and could achieve new steady states with high propionate removal after a certain period.When the HRT was gradually decreased from 10 h to 4 h,the specific COD_proremoval of anaerobic sludge in the UASB system was increased to 1.7 kg/(kg·d) from 1.2 kg/(kg·d).The decrease of HRT made the band 2-4(Syntrophobacter fumaroxidans),propionate-oxidizing bacteria enriched gradually in UASB system,and the band 5(S.sulfatireducens) reduced,while band 1 and band 6(Pelotomaculum propionicicum) maintained a relatively stable level.The enrichment of band 2-4 with high specific degradation rate resulted in the propionate removal to 94.1% under organic loading rate of 18 kg/(m~3·d).更多还原