氟化工废水处理系统中活性污泥的耐毒性及微生物群落结构特征分析

氟化工废水具有毒性强、有机负荷高、可生化性差及水质成分复杂等特征,采用功能微生物技术降解氟化工混合废水是当前水处理研究的热点问题.本研究以某氟化工企业污水处理厂一期工程活性污泥S1、二期工程活性污泥S2及城市污水处理厂活性污泥S3为对象,研究3种污泥对氟化工混合废水的耐毒性和微生物群落结构特征.通过Strathtox活性污泥呼吸仪测得污泥S1、S2、S3在葡萄糖模拟废水中的最佳呼吸速率分别为(174.00±1.14)、(189.20±1.11)、(134.50±2.30)mg·L~(-1)·h~(-1),表明3种污泥具有初始活性;在氟化工原始废水中平均呼吸速率分别仅为(5.60±0.70)、(8.87±0.97)、(5.83±0.25)mg·L~(-1)·h~(-1),说明氟化工原始废水存在抑制微生物正常代谢的有毒有害物质.通过固相萃取获得的氟化工有机混合废水实验表明,3种污泥最佳呼吸速率分别为(53.02±0.79)、(68.60±0.96)、(38.10±1.06)mg·L~(-1)·h~(-1),与原始废水中的呼吸状况相比,3类污泥的呼吸作用有显著增强,表明3种活性污泥对氟化工有机混合废水有较强的适应性.应用PCR-DGGE技术对3种活性污泥的微生物多样性研究表明,3种活性污泥微生物多样性较为明显,其中,污泥S1的香浓布朗指数达到1.69.通过进一步的切胶克隆测序,成功鉴定出Kineococcus gynurae等6种能够适应氟化工有机混合废水的优势菌种.验证实验证实,污泥S2对初始总有机碳浓度为250 mg·L~(-1)的氟化工有机废水降解率达到70%,表明氟化工原始废水经过脱盐和消除重金属处理后,其可生化性显著增强.上述研究结果为氟化工混合废水高效处理工艺的开发提供了重要理论依据.

Tolerance abilities and microbial community characteristics of activated sludges in fluoride wastewater treatment plants

Due to the high toxicity, high organic loading, poor biodegradability and complicated components of fluorine chemical wastewater,it is a key issue to treat fluorine containing wastewater by the functional microbe. In this study, three kinds of activated sludge named S1, S2 and S3 were used to study the toxicity-tolerance abilities and microbial community characteristics. Both S1 and S2 were collected from the fluorine chemical industrial wastewater treatment units, while S3 was collected from a domestic wastewater treatment unit. Respiration rates of activated sludge were measured by means of a Strathtox Respirometer. The results show that the optimal respiration rates of sludge S1, S2, S3 in glucose wastewater were (174.00±1.14),(189.20±1.11) and (134.50±2.30) mg·L^-1·h^-1, respectively. In fluorine chemical wastewater, their optimal respiration rates were only (5.60±0.70), (8.87±0.97) and (5.83±0.25) mg·L^-1·h^-1, respectively. It was clearly indicated that there were harmful substances in wastewater that were toxic to activated sludge. Furthermore, by the solid-phase-extraction (SPE) purification method, mixed organic fluorine chemical wastewater was made. It was found that the optimal respiration rates of sludge in such kind of wastewater were (53.02±0.79), (68.60±0.96) and (38.10±1.06) mg·L^-1·h^-1, respectively. It was implied that the microbes in all the sludge had the adaptabilities for the purified organic fluorine chemical wastewater. The PCR-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) analyses illustrated that the microbe diversities of all these sludge were significant and the Shannon-Brown index of S1 was even 1.69. By cloning and sequencing analyses, 6 kinds of dominant functional microorganisms such as Kineococcus gynurae were identified. It was found that they can adapt the fluoride chemicals containing organic wastewater. The verification experimental results further proved that the total organic carbon (TOC) degradation rate by sludge S2 was above 70% for the fluorine chemical organic wastewater with the initial TOC content of 250 mg·L^-1. It was demonstrated that after the desalination and the elimination of heavy metals the biodegradability of the fluoride chemical raw wastewater can be greatly enhanced. All the results can provide the theoretical basis of the technique development for the treatment of the fluoride chemical wastewater.