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抗生素与重金属对猪场废水厌氧消化的抑制效应及其调控对策

Inhibitory Effect of Antibiotics and Heavy Metals on Anaerobic Digestion of Piggery Wastewater and Its Control Strategy

【作者】 孙建平

【导师】 郑平;

【作者基本信息】 浙江大学 , 环境工程, 2009, 博士

【摘要】 厌氧消化技术被广泛应用于猪场废水处理工程中,但废水中所含的抗生素和重金属等特殊污染物会对废水的厌氧消化产生自抑制作用,影响工程稳定运行。为了探明抗生素和重金属的抑制状况,消除抑制物对厌氧消化的影响,以发光细菌毒性试验和厌氧消化抑制试验为基础,系统研究了抗生素和重金属的独立抑制、联合抑制、蓄积抑制等,提出了“识别筛选-重点清除”调控对策。主要成果如下:(1)研究了猪场废水的综合毒性。水质分析表明猪场废水中含有抗生素阿莫西林、氟苯尼考、金霉素、磺胺二甲氧,同时含有重金属铜、锌、铬等毒性成分。发光细菌法测定表明,猪场废水的毒性相当于18.2mg/L氯化汞。厌氧消化抑制试验表明猪场废水具有较强的自抑制作用。以氯化汞半抑制浓度为指标,抗生素和重金属对猪场废水毒性的贡献率分别为31%和23%。(2)研究了抗生素的抑制效应。发光细菌毒性试验表明,猪场废水中常见的几种抗生素均具毒性,其毒性强弱依次为金霉素、氟苯尼考、阿莫西林、磺胺二甲氧,IC50值分别为1.17mg/L、15.45mg/L、78.62mg/L、83.00mg/L;抗生素各水平组合对发光细菌均具有毒性,相对发光度抑制率为12.1%~79.5%,联合毒性表现为相加或拮抗作用;厌氧消化试验表明,所试抗生素对厌氧消化均具有抑制作用,抑制强弱顺序与发光细菌试验法所得的毒性强弱顺序相同;以蔗糖、丁酸盐和乙酸盐为基质厌氧消化试验表明,金霉素和阿莫西林对水解发酵和产氢产乙酸的抑制效应强于产甲烷。(3)研究了重金属的抑制效应。发光细菌毒性试验表明,猪场废水中常见的几种重金属均具毒性,其毒性强弱依次为Cu(Ⅱ)、Zn(Ⅱ)、Cr(Ⅲ),IC50值分别为0.68mg/L、1.18mg/L、11.32mg/L;重金属离子各水平组合均具毒性,相对发光度抑制率为41.40%~93.0%,联合毒性表现为相加或拮抗作用;厌氧消化试验表明,所试三种重金属离子对厌氧消化均具有抑制效应,抑制强弱顺序与发光细菌试验法所得的毒性强弱顺序相同;以蔗糖、丁酸盐和乙酸盐为基质厌氧消化试验表明,三种重金属离子对水解发酵和产氢产乙酸的抑制作用均强于产甲烷。(4)研究了抗生素和重金属的联合抑制效应。发光细菌毒性试验和厌氧消化抑制试验表明,抗生素和重金属的联合均具有抑制效应,对发光细菌发光强度的抑制率为44%~100%,对厌氧消化累积产甲烷量抑制率为27.88%~83.65%,三种抑制剂的联合毒性表现为相加和拮抗作用。(5)提出了“识别筛选-重点清除”调控对策,并进行了验证。经正交试验,识别筛选出猪场废水中的主要抑制因子有金霉素、Cu(Ⅱ)和Zn(Ⅱ),采用预处理重点清除后,其抑制物浓度为8.0mg/L、1.0mg/L和1.2mg/L;经预处理后猪场废水的厌氧消化效率提高,稳定性增强,该对策可用于指导工程实践。

【Abstract】 Anaerobic biological treatment(anaerobic digestion) is widely used in piggery wastewater treatment process, however, antibiotics and heavy metals as special contaminants in this kind of wastewater have self-inhibition effect on the biotreatment technology. To find the law of the inhibitory effect of antibiotics and heavy metals on anaerobic biological treatment the photobacteria toxicity test and anaerobic digestion inhibition test were adopted. The rule of the individual inhibition, the joint inhibition, and the accumulative inhibition of antibiotics and heavy metals were studied through statistical methods. "Identification-Removal" control strategy was proposed to eliminate the inhibitory effect on anaerobic biological treatment. The main results are as follows:(1) Study on the general toxicity of piggery wastewater. The results showed that the toxicity of piggery wastewater was in equivalent to 18.2mg/L of mercury chloride. The piggery wastewater has strong self-inhibition on anaerobic digestion. The contribution percentages of antibiotics and heavy metals to the general toxicity of piggery wastewater were separately 31% and 23%.(2) Study on the inhibitory effect of antibiotics. The results of photobacteria toxicity test showed that the order of antibiotics toxicity was aureomycin > florfenicol > amoxicillin) sulfamethazine, of which the IC50 value were 1.17mg/L, 15.45mg/L, 78.62mg/L, and 83.00mg/L, respectively. The different levels of antibiotics had inhibitory effects on relative light illumination intensity of photobacteria and the inhibitory ratio of illuminatioin intensity was 12.1%~79.5%. The joint toxicity of four kinds of antibiotics was antagonistic or additive. Results of anaerobic digestion experiments indicated that the order of inhibory effect was the same as the result of photobacteria experiments and aureomycin was the strongest in the four kinds of antibiotics. The results of sensitive step test showed that hydrolysis fermentation and hydrogen-production acetogenisis were the rate-limiting steps in the inhibition of aureomycin or amoxicillin.(3) Study on the inhibitory effect of heavy metals. The results of photobacteria toxicity test indicated that the order of heavy metals toxicity was Cu (Ⅱ)、Zn (Ⅱ)、Cr (Ⅲ), of which the IC50 value were 0.68mg/L, 1.18mg/L, and 11.32mg/L, respectively. The different levels of heavy metals had inhibitory effects on relative light illumination intensity of photobacteria and the inhibitory ratio of illuminatioin intensity was 41.4%~93.0%. The joint toxicity of three kinds of heavy metals was antagonistic or additive. Results of anaerobic digestion experiments indicated that the order of inhibory effect was the same as the result of photobacteria experiments. The inhibitory effect of Cu (Ⅱ) was the strongest in the three kinds of the factors and the inhibitory effect of Zn (Ⅱ) was highly accumulative. The results of sensitive step test showed that hydrolysis fermentation and hydrogen-production acetogenisis were the rate-limiting steps in the inhibition of heavy metals.(4) Study on the joint inhibitory effect of antibiotic and heavy metals. The results of photobacteria toxicity test and anaerobic digestion test indicated that the different levels of antibiotic and heavy metals had inhibitory effects on relative illumination intensity and anaerobic digestion. The inhibitory ratio of illuminatioin intensity and accumulative methane production were 44.0%~100.0% and 27.88%~83.65%, respectively. The interaction between aureomycin and Cu (Ⅱ) was antagonistic and was of additive effect between aureomycin and Zn(Ⅱ).(5) The "Identification and Removal" control strategy was proposed for anaerobic digestion of piggery wastewater. The results showed that Aureomycin, Cu (Ⅱ) and Zn (Ⅱ) were significant factors, the inhibitory concentration of which were 8.0mg/L, 1.0mg/L and 1.2mg/L, respectively. The effectiveness and stability of anaerobic digestion was increased significantly after piggery wastewater was pretreated. The "Identification-Removal" control strategy can be used as a guide to the engineering practice.

  • 【网络出版投稿人】 浙江大学
  • 【网络出版年期】2011年 02期
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