土霉素对SBR系统脱氮性能的抑制作用研究

发布时间：2018-03-06 02:12

本文选题：SBR系统　切入点：土霉素　出处：《浙江工商大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,大量的土霉素(OTC)已被应用于医药以及畜牧业。由于土霉素只有少部分能够被生物降解,因此大量土霉素会排入至水环境中。污水中存在的土霉素可能会对生物污水处理系统中的微生物(尤其是功能性微生物如硝化菌和反硝化菌等)产生不良影响,从而导致生物污水处理系统的污水处理效果不理想。因此,研究土霉素对污水处理厂中生化过程的影响是十分必要的。本试验接种污泥为杭州市七格污水处理厂曝气池出口污泥,经过实验室驯化,SBR系统脱氮效率稳定在95.0%以上,去除CODcr效果显著。本文基于SBR系统,从脱氮过程、化学需氧量(CODcr)的去除过程、胞外聚合物(EPS)的总量变化过程、比呼吸速率(SOUR)的变化过程以及微生物群落的变化等多个角度出发,较系统地研究了不同浓度土霉素对SBR系统的冲击作用。结果表明,由于土霉素的作用,系统的氨氮去除率从99.0%分别下降至77.2%(1 mg L-1)、47.4%(5 mg L-1)以及6.66%(10 mg L-1),在30天抑制试验之后的15天恢复阶段内,R2(mgL-1)、R3(5mgL-1)反应器具有较好恢复性,而R4(10 mg L-1)反应器恢复性较差。缺氧段CODcr去除率从89.51%分别下降至 84.55%(1 mg L-1)、16.23%(5 mg L-1)以及 2.51%(10 mg L-1),在恢复阶段出现不同程度恢复,但无法恢复至初始水平。此外,高浓度土霉素(10 mg L-1)引起EPS分泌量和异养菌SOUR分别下降至空白组的44.3%和41.2%。由高通量分析可得,由于高浓度土霉素(5mgL-1以上)的作用,活性污泥中微生物的多样性显著下降,且微生物的群落结构也发生显著变化。系统中的微生物的变形菌门比例不断下降,而拟杆菌门比例出现上升,该发现有助于后续相关试验对某些特定菌种的筛选作用。属层面的分析可得,高浓度土霉素(5mgL-1以上)反应器中的部分氨氧化菌,例如Nitrospira和Nitrosomonas均受到了抑制;缺氧异养菌聚糖菌(Candidatus_Competibacter)比例下降明显,与宏观数据氨氮和CODCr去除效率下降相符。菌胶团Zoogloea比例上升,发生非丝状菌膨胀。
[Abstract]:In recent years, a large number of oxytetracycline (OTC) have been used in medicine and animal husbandry, because only a small part of oxytetracycline can be biodegraded. Therefore, a large amount of oxytetracycline is discharged into the water environment. The presence of oxytetracycline in sewage may have a negative effect on microorganisms in the biological wastewater treatment system (especially functional microorganisms such as nitrifying bacteria and denitrifying bacteria, etc.). As a result, the sewage treatment effect of the biological sewage treatment system is not ideal. It is necessary to study the effect of oxytetracycline on the biochemical process in wastewater treatment plant. The sludge inoculated in this experiment is the outlet sludge of the aeration tank of the seven wastewater treatment plants in Hangzhou. The denitrification efficiency of the system is stable at more than 95.0% after the laboratory acclimation. The removal effect of CODcr is remarkable. Based on the SBR system, this paper starts from the denitrification process, the removal process of chemical oxygen demand (COD), the total change process of extracellular polymer (CODcr), the change process of specific respiration rate (CODcr), and the change of microbial community, etc. The impact of different concentrations of oxytetracycline on SBR system was systematically studied. The removal rate of ammonia nitrogen in the system decreased from 99.0% to 77.2 mg L -1, 47.44 mg L -1 and 6.66 mg L -1, respectively. During the 15-day recovery period after the 30-day inhibition test, the R2mgL-1 / R3GL-1) reactor had a good recovery, and the total ammonia nitrogen removal rate decreased from 99.0% to 77.2mgL-1, 47.4mg / L, 47.4mg / L and 6.66mg / L ~ (-1), respectively. During the 15-day recovery period after the 30-day inhibition experiment, the reactor was of good restorability. The CODcr removal rate of the anoxic stage decreased from 89.51% to 84.551mg / L and 16.23235mg / L, respectively, and the recovery of 10mg / L ~ (-1) and 2.51g / L ~ (10 mg / L ~ (-1)) showed different degrees of recovery, but could not recover to the initial level. High concentration oxytetracycline (10 mgL-1) reduced the secretion of EPS and SOUR of heterotrophic bacteria to 44.3% and 41.2in blank group, respectively. By high-throughput analysis, the microbial diversity in activated sludge decreased significantly due to the effect of high concentration of oxytetracycline (> 5 mg 路L ~ (-1)). And the community structure of microorganism also changed significantly. The proportion of Proteus phylum of microorganism in the system decreased continuously, but the proportion of Bacteroides increased. This finding is helpful to the screening of certain strains in the subsequent related tests. At the generic level, some ammonia-oxidizing bacteria, such as Nitrospira and Nitrosomonas, were inhibited in the reactor with high concentration of oxytetracycline (> 5 mg 路L ~ (-1)). The proportion of anoxic heterotrophic bacteria Candidatus Competitive bacteria decreased obviously, which was consistent with the decrease of the removal efficiency of ammonia nitrogen and CODCr in macroscopical data. The ratio of Zoogloea of micelle increased and the expansion of non-filamentous bacteria occurred.
【学位授予单位】：浙江工商大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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