煤炭地下气化废水的微生物修复研究

Study on microbial remediation of underground coal gasification wastewater

煤炭地下气化产生的废水污染直接限制了该技术的推广应用,针对此问题,采用筛选到的降解苯酚菌JP和降解萘菌KN,对模拟煤炭地下气化产生的废水进行降解修复试验。结果表明:经过72 h培养,煤炭地下气化废水的TOC下降80%以上,有机污染物种类减少近50%,酚类、杂环化合物、多环芳烃为代表的有机污染物种类和质量浓度减幅明显;重金属离子质量浓度均有所降低,Pb,Cd,Cu质量浓度降幅较大,最高可达100%;降解菌能在煤炭地下气化废水中存活,并能有效去除有机污染物和重金属离子。降解机理研究表明,JP菌降解煤炭地下气化废水中的吲哚时与喹啉和酚类物质存在共代谢,其对喹啉的降解遵循吡啶环开环途径;KN菌对喹啉的降解同时存在苯环开环与吡啶环开环2种途径,对多环芳烃的降解遵循水杨酸途径;两菌混合在对中间产物和终产物的利用上存在协同机制,有利于有机污染物的彻底清除。

The risk of groundwater pollution caused by underground coal gasification directly limits the application of this technology. In this paper,the phenol degrading bacteria JP and naphthalene degrading bacteria KN were selected to degrade and repair the gas washing water produced by simulated underground coal gasification. After 72 hours of culture,the TOC value of gas washing water decreased by more than 80%,the types of organic pollutants decreased by nearly half,the types and concentrations of highly toxic organic pollutants represented by phenols,heterocyclic compounds and polycyclic aromatic hydrocarbons decreased significantly.The concentration of heavy metal ions decreased,and the concentration of Pb,Cd and Cu decreased greatly,even up to 100%. The results showed that the degrading bacteria could survive in underground coal gasification wastewater and could effectively remove organic pollutants and heavy metal ions. The degradation mechanism showed that JP bacteria had a cometabolism with quinoline and phenols when degrading indole in gas washing water,and its degradation of quinoline followed the pyridine ring opening pathway. The degradation of quinoline by KN bacteria had two ways as benzene ring opening and pyridine ring opening,and the degradation of aromatic hydrocarbons follows the salicylic acid path. There was a synergistic mechanism in the utilization of intermediate products and end products,which was conducive to the complete removal of organic pollutants.