The College of Material and Environment Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang, China.
The Institute of Municipal Engineering, The College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, Zhejiang, China.
Environ Res. 2021 Mar;194:110642. doi: 10.1016/j.envres.2020.110642. Epub 2020 Dec 19.
Bio-clogging is a major problem in the operation of constructed wetlands (CWs) and is caused by accumulation of biofilm and extracellular polymeric substances (EPS) in the substrate. B. subtilis can successfully produce α-amylase and endoglucanase, which can degrade polysaccharides and, consequently, disperse the EPS. Therefore, the addition of B. subtilis was used to decrease the bio-clogging of lab-scale vertical-flow constructed wetlands (VFCW) in this study, and the feasibility and performance of VFCWs were assessed. The results indicate that the addition of B. subtilis can degrade the polysaccharides in the clogging matter and thereby increase the porosity of the substrate. The hydraulic conductivity of Column 1 (with addition) increased by six times, which was 57 times that of control (Column 2). Meanwhile, the chemical oxygen demand (COD) removal rate also increased after the addition of B. subtilis. The microbial communities show that the richness and diversity within the substrate increased after addition. The relative abundance of functional groups of chemoheterotrophy, aerobic chemoheterotrophy, as well as that connected to N cycles also increased, which implied the improvement of the pollution removal efficiency. Meanwhile, the copy number of α-amylase and endoglucanase increased significantly in Column 1 with the addition of B. subtilis, which offers further support for a hydrolase-induced reduction of polysaccharides and the efficiency of B. subtilis on bio-clogging alleviation. The results showed that B. subtilis addition is an effective and safe solution to control the bio-clogging for CWs. However, further research about long-term effect assessment and dosing strategy optimization should be conducted.
生物堵塞是人工湿地（CWs）运行中的一个主要问题，是由生物膜和细胞外聚合物（EPS）在基质中的积累引起的。枯草芽孢杆菌可以成功地产生α-淀粉酶和内切葡聚糖酶，这两种酶可以降解多糖，从而分散 EPS。因此，本研究中添加枯草芽孢杆菌以减少实验室规模的垂直流人工湿地（VFCW）的生物堵塞，并评估了 VFCWs 的可行性和性能。结果表明，添加枯草芽孢杆菌可以降解堵塞物中的多糖，从而增加基质的孔隙率。（添加枯草芽孢杆菌的）第 1 柱的水力传导率增加了六倍，是对照（第 2 柱）的 57 倍。同时，添加枯草芽孢杆菌后，化学需氧量（COD）去除率也有所提高。微生物群落表明，添加后基质内的丰富度和多样性增加。化能异养、好氧化能异养以及与 N 循环相关的功能组的相对丰度也增加了，这意味着去除污染的效率得到了提高。同时，添加枯草芽孢杆菌后第 1 柱中α-淀粉酶和内切葡聚糖酶的拷贝数显著增加，这进一步支持了水解酶诱导多糖减少和枯草芽孢杆菌对生物堵塞缓解的效率。结果表明，添加枯草芽孢杆菌是控制 CWs 生物堵塞的一种有效且安全的解决方案。然而，应该进行进一步的关于长期效果评估和剂量策略优化的研究。
