红霉素与土霉素对EBPR系统的抑制机制研究

发布时间：2018-05-03 05:27

本文选题：强化生物除磷系统 + 红霉素　；参考：《浙江工商大学》2017年硕士论文

【摘要】：近年来,由于抗生素的大量使用且只有少部分能够被生物体所降解,因此大量的剩余抗生素通过各种途径排放至水体环境,尤其是污水处理厂中,其浓度为ng/L-μg/L。然而,在某些制药废水中抗生素浓度可以达到mg/L级别。抗生素存在于污水处理系统中可能对系统中的微生物,尤其是功能性微生物如聚磷菌(phosphate accumulating organisms,PAOS),硝化菌和反硝化菌等产生不良影响,从而导致系统的污水处理能力下降。因此,研究抗生素对于污水处理厂中各种生化过程的影响是相当有必要的。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120天驯化,EBPR系统除磷效率长期稳定在100%。本文基于强化生物除磷(EBPR)系统,从除磷过程、挥发性脂肪酸(VFA)的消耗过程、聚羟基脂肪酸酯(PHAs)的合成与消耗过程、胞外聚合物(EPS)分泌量的变化过程,比呼吸速率(SOUR)的变化过程以及微生物群落的变化过程等多个角度出发,比较系统地研究了红霉素,土霉素及其混合抗生素对EBPR系统的作用。24小时试验结果表明,高浓度(10mg/L)红霉素和土霉素在24小时内均能对除磷过程产生明显的抑制作用,除磷效率分别下降至63.3%和61.2%。高浓度(10 mg/L)抗生素对VFA的消耗过程并无明显作用,但对PHAs的厌氧合成和好氧消耗过程影响较为显著。同时,高浓度(10mg/L)抗生素对EPS中PN合成量的抑制率在26.7%以上。SOUR变化过程的分析结果表明,抗生素对EBPR系统中微生物的呼吸作用抑制显著,在高浓度(10 mg/L)抗生素反应器中抑制率在16.00%%以上。对比分析结果表明,相同浓度的土霉素比红霉素对EBPR系统的抑制效果更为显著,且EBPR系统的好氧过程比厌氧过程更容易受到抑制。同时,7天试验结果表明,虽然各类抗生素对于宏观指标变化过程包括除磷过程、VFA的消耗过程、PHAs的合成与消耗过程、EPS分泌量的变化过程以及SOUR变化过程等过程的抑制程度相似,但是各抗生素反应器中菌群结构的变化却截然不同。相比于低浓度(1 mg/L)抗生素,高浓度(5,10 mg/L)抗生素反应器中菌落多样性下降更为显著。同时,相似性分析表明,相比较于低浓度(1m/L)抗生素,高浓度(5,10mg/L)抗生素引起了系统中更为显著的菌群结构变化。另外,混合抗生素反应器中菌落结构的变化比单一抗生素反应器中的菌群结构变化更为显著。Accumulibacter和Competibacter是EBPR系统在属层面占比最高的两种菌。经过抗生素7天的作用,Accumulibacter作为一类主要的PAOs,其在系统中的占比明显下降。然而,Competibacter作为一类主要的聚糖菌(glycogen-accumulating organisms,GAOs),其在系统中的占比明显上升。在红霉素、土霉素以及其混合抗生素存在的条件下,GAOs更有竞争优势。最后,经各类抗生素作用7天之后,各反应器中的抗性菌也表现出明显的不同。
[Abstract]:In recent years, due to the extensive use of antibiotics and only a few of them can be degraded by organisms, a large number of surplus antibiotics are discharged into the water environment through various ways, especially in sewage treatment plants, whose concentration is ng / L-渭 g / L. However, antibiotic concentrations in some pharmaceutical wastewater can reach mg/L level. The presence of antibiotics in the wastewater treatment system may have a negative effect on the microbes in the system, especially on the functional microorganisms such as Phosphorus accumulating organismsorganisma, nitrifying bacteria and denitrifying bacteria, resulting in a decrease in the system's sewage treatment capacity. Therefore, it is necessary to study the effects of antibiotics on various biochemical processes in wastewater treatment plants. The sludge inoculated in this experiment is the outlet sludge of aeration tank in seven wastewater treatment plants of Hangzhou. After 120 days of acclimation, the phosphorus removal efficiency of EBPR system is stable at 100 for a long time. Based on the enhanced biological phosphorus removal (EBPRR) system, the process of phosphorus removal, the consumption of volatile fatty acids (VFAs), the synthesis and consumption of polyhydroxyl fatty acid esters (PHASs), and the changes of EPS-exudation of extracellular polymers (EPSs) were studied in this paper. The effects of erythromycin, oxytetracycline and their mixed antibiotics on EBPR system were systematically studied. Erythromycin and oxytetracycline at high concentration of 10 mg 路L ~ (-1) could significantly inhibit the phosphorus removal process within 24 hours, and the phosphorus removal efficiency decreased to 63.3% and 61.2%, respectively. High concentration of 10 mg / L antibiotics had no obvious effect on the consumption of VFA, but had a significant effect on the anaerobic synthesis and aerobic consumption of PHAs. At the same time, the inhibitory rate of high concentration of 10 mg / L antibiotics on the synthesis of PN in EPS was over 26.7%. The results showed that antibiotics inhibited the respiration of microbes in EBPR system significantly. In a 10 mg / L high concentration antibiotic reactor, the inhibition rate was above 16.00%. The results showed that oxytetracycline of the same concentration was more effective than erythromycin in inhibiting EBPR system, and the aerobic process of EBPR system was more easily inhibited than that of anaerobic process. At the same time, the results of 7-day test showed that the inhibition degree of all kinds of antibiotics to the process of macroscopical index change, including the process of phosphorus removal, the process of consumption of SOUR and the process of synthesis and consumption of PHAs, and the process of change of SOUR, were similar. However, the changes of microbial structure in antibiotic reactors are quite different. Compared with a low concentration of 1 mg / L antibiotic, the colony diversity in a 10 mg / L high concentration antibiotic reactor decreased significantly. At the same time, the similarity analysis showed that compared with the low concentration of 1 mg / L antibiotic, the high concentration of 10 mg / L antibiotic caused a more significant change in the microflora structure in the system. In addition, the change of colony structure in the mixed antibiotic reactor was more significant than that in the single antibiotic reactor. Accumulibacter and Competibacter were the two strains with the highest proportion in the EBPR system at the generic level. As a major class of PAOss, the proportion of Accumulibacter in the system decreased significantly after 7 days of antibiotic treatment. However, the percentage of Competibacter in the system, as a major group of glycogen-activating organisms, has increased significantly. In the presence of erythromycin, oxytetracycline and its mixed antibiotics, GAOs have a more competitive advantage. Finally, after 7 days of exposure to various antibiotics, the resistant bacteria in each reactor showed significant differences.
【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

【参考文献】