研究报告
黄斯艺,何江涛,何宝南,赵谢洁.地下水硝酸盐反硝化修复过程中生物膜抑制缓堵模拟实验研究[J].环境科学学报,2022,42(4):186-194
地下水硝酸盐反硝化修复过程中生物膜抑制缓堵模拟实验研究
- Biofilm inhibition and porous media clogging mitigation in nitrate denitrification remediation
- 基金项目：中央高校基本科研业务费项目（No.2652019295）
- 作者
- 单位
- 黄斯艺
- 中国地质大学（北京）水资源与环境工程北京市重点实验室，北京 100083
- 何江涛
- 中国地质大学（北京）水资源与环境工程北京市重点实验室，北京 100083
- 何宝南
- 中国地质大学（北京）水资源与环境工程北京市重点实验室，北京 100083
- 赵谢洁
- 中国地质大学（北京）水资源与环境工程北京市重点实验室，北京 100083
- 摘要：为缓解地下水污染原位生物修复过程中生物膜形成造成的多孔介质渗透性损失，采用纳米乳化油为碳源，市售反硝化细菌为菌种，开展静态批实验，模拟地下水硝酸盐氮反硝化修复过程；选取蛋白酶、多糖酶以及群体感应抑制剂香草醛为生物膜抑制剂，分析不同反应体系硝酸盐氮的降解情况，探究3种添加物的不同组合方式对于反硝化细菌生物膜的抑制作用.结果显示，多糖酶、蛋白酶以及香草醛的投加能够有效促进硝酸盐氮的降解和亚硝酸盐氮的还原.4个实验组别的NO3-N降解速率为0.28~0.30 mg·L-1·h-1，约为空白组的2.55~2.73倍，且NO2-N无明显积累.群体感应抑制剂香草醛与蛋白酶的结合对以假单细胞菌属为主的反硝化细菌生物膜的抑制效果最好.定量评估结果表明，生物膜去除效果依次为香草醛和蛋白酶的混合物（81.3%）＞蛋白酶和多糖酶的混合物（68.6%）＞蛋白酶（54.1%）＞多糖酶（49.1%），单位质量多糖酶、蛋白酶和香草醛对于胞外聚合物的去除量分别为30.07、65.34 mg·mL-1和0.71 mg·mg-1.基于多孔介质一维柱概念模型计算显示，投加不同添加物的实验组中多孔介质渗透性损失均存在不同程度的恢复，在中砂和细砂介质中，其恢复程度分别为15.0%~33.2%和16.2%~34.0%.反硝化细菌所分泌的粘性胞外聚合物是造成多孔介质生物堵塞的主要原因.
- Abstract：To alleviate the permeability loss of porous media caused by the formation of biofilm in the process of in-situ bioremediation of contaminated groundwater， experiments were conducted with reactors in which microorganisms were inoculated with denitrifying bacteria， and nano emulsified oil was used as carbon source to simulate the process of nitrate denitrification remediation. Protease， polysaccharase and quorum sensing inhibitor vanillin were selected as biofilm inhibitors to investigate the nitrate removal in different reaction systems， and explored the biofilm inhibition using different combination of three inhibitors. The results showed that polysaccharase， protease and vanillin could effectively promote the nitrate removal and the reduction of nitrite nitrogen. The NO3-N removal rate of the four experimental groups was 0.28~0.30 mg·L-1·h-1， which was 2.55~2.73 times higher than that of the control reactor， and there was no significant accumulation of nitrite. The combination of vanillin， a quorum sensing inhibitor， and protease had the best inhibition performance on denitrifying biofilm. The results of quantitative evaluation showed that the removal efficiency of biofilm， from high to low， was ordered as： the mixture of vanillin and protease （81.3%） > the mixture of protease and polysaccharase （68.6%） > protease （54.1%） > polysaccharase（49.1%）. The removal rates of extracellular polymeric substances per unit mass of polysaccharase， protease and vanillin were 30.07 mg·mL-1， 65.34 mg·mL-1 and 0.71 mg·mg-1， respectively. The results of one-dimensional column model of porous media showed that the permeability loss of porous media in the experimental groups with different inhibitors had different recovery rate. The permeability recovery of medium sand and fine sand were 15.0%~33.2% and 16.2%~34.0%， respectively. The extracellular polymeric substances secreted by denitrifying bacteria is the main reason for the bioclogging of porous media.
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