School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, China; Department of Civil and Environmental Engineering, Water Technology Center, Hong Kong Branch of Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science & Technology, Clear Water Bay, Hong Kong.
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, China.
Environ Res. 2021 Apr;195:110838. doi: 10.1016/j.envres.2021.110838. Epub 2021 Feb 10.
The existence of abundant biofilms on sewer pipeline walls can lead to negative environmental impacts, such as poisonous gas release and pipe corrosions through transforming various pollutants. Investigating the formation process of sewer biofilms is of importance in advancing knowledge of sewer operation and maintenance. In this study, the changes in physical characteristics, microstructure, and microbial communities of sewer biofilm were analyzed in-depth in a pilot-scale gravity sewer during a 45-day operation. The results show that a high specific surface area at the early stage could channel the substrates for stimulating the primary colonizers (e.g., Cytophagia, Sphingobacteriia, Alpha-, and Betaproteobacteria), which could excrete an extracellular matrix to facilitate biofilm growth. The sewer biofilms were gradually formed with 62 g VS/m organic content, 1.2 mm biofilm thickness, and 89 mg/cm dry density after 45 days operation. Moreover, the biofilm growth promoted the emergence of facultative bacteria and anaerobes (affiliated with Flavobacteriia, Gemmatimonadetes, Deltaproteobacteria, and Epsilonproteobacteria). Microelectrode analysis further verified that an anaerobic zone existed in mature biofilm with a negative oxidation-reduction potential (-105 mV), where approximately 0.1 μmol/L of sulfide was produced. Our results suggest that the migration of the microbial community correlated with the changes in the evolved physical characteristics and microstructure of sewer biofilm, and this can contribute to the strategies for sulfide control for improving sewer maintenance.
污水管道壁上大量生物膜的存在会导致负面的环境影响，例如通过转化各种污染物释放有毒气体和腐蚀管道。研究污水生物膜的形成过程对于推进污水运行和维护知识具有重要意义。在这项研究中，在一个 45 天的运行中，在一个中试规模的重力污水管中深入分析了污水生物膜的物理特性、微观结构和微生物群落的变化。结果表明，在早期阶段具有高比表面积可以为刺激主要定植菌（例如 Cytophagia、Sphingobacteriia、Alpha- 和 Betaproteobacteria）的基质提供通道，定植菌可以分泌细胞外基质来促进生物膜的生长。经过 45 天的运行，污水生物膜逐渐形成，有机含量为 62 g VS/m，生物膜厚度为 1.2 mm，干密度为 89 mg/cm。此外，生物膜的生长促进了兼性菌和厌氧菌（与 Flavobacteriia、Gemmatimonadetes、Deltaproteobacteria 和 Epsilonproteobacteria 有关）的出现。微电极分析进一步证实，成熟生物膜中存在一个无氧区，其氧化还原电位为负（-105 mV），大约产生 0.1 μmol/L 的硫化物。我们的研究结果表明，微生物群落的迁移与污水生物膜演变的物理特性和微观结构的变化相关，这有助于制定控制硫化物的策略，以改善污水维护。
