Control strategies for biofilm control in reclaimed water distribution systems from the perspective of microbial antagonism and electrochemistry

Tianzhi Wang; Tianjiao Zhang; Xingda Dai; Weijie Wang; Jiehua Wang

doi:10.1016/j.scitotenv.2022.155289

Control strategies for biofilm control in reclaimed water distribution systems from the perspective of microbial antagonism and electrochemistry

Sci Total Environ. 2022 Aug 15:834:155289. doi: 10.1016/j.scitotenv.2022.155289. Epub 2022 Apr 18.

Authors

Tianzhi Wang¹, Tianjiao Zhang², Xingda Dai², Weijie Wang², Jiehua Wang³

Affiliations

¹ School of Environmental Science & Engineering, Tianjin University, Tianjin 300350, China; College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China.
² School of Environmental Science & Engineering, Tianjin University, Tianjin 300350, China.
³ School of Environmental Science & Engineering, Tianjin University, Tianjin 300350, China. Electronic address: jiehuawang@tju.edu.cn.

PMID: 35447190
DOI: 10.1016/j.scitotenv.2022.155289

Abstract

Biofilm formation in reclaimed water (RW) distribution systems presents significant technical challenges to RW utilization. Two main technologies to control biofilm formation, microbial antagonism (MA) and electrochemical oxidation (EO), are not yet widely used in drip irrigation systems (DIS) and their mechanisms of action need further clarification. In this study, we first showed that the MA and EO treatments reduced biofilm formation by about 62% and 68%, respectively, and extracellular polymeric substance (EPS) content by 14% and 49%, respectively, in biofilms compared with raw RW type 1 (R-RW1) in unused pipes, thus effectively improving the performance of DIS. When MA-RW and EO-RW were applied to already clogged systems, the degree of clogging alleviation varied depending on the severity of the original clogging. We recommend adding the antagonist, Bacillus subtilis, to RW at 25% clogging for the maximum effect and to slow the microbial adaptation process. Compared to MA, the recovery effect of EO was slower initially but lasted longer and had a significantly better alleviating effect on severely clogged pipelines. Illumina Mi-SEQ high-throughput sequencing data showed that both MA and EO resulted in a significant decrease in microbial diversity, dynamic changes in bacterial community structure, and disruption of network interaction and network modularity. Meanwhile, both treatments promoted the growth of specific microorganisms, enhanced the interaction between certain microbial components, and improved the efficiency of information, matter, and energy exchange within the modules. In summary, we verified the dredging effect of two strategies on DIS under different water conditions, revealed the differences in their mechanisms of action, and proposed their application scenarios. Our results will help improve the efficiency of RW in agricultural drip irrigation systems and effectively reduce maintenance costs.

Keywords: Biofilm; Drip distribution systems; Electrochemical oxidation (EO); Microbial antagonism (MA); Reclaimed water (RW).

MeSH terms

Antibiosis
Biofilms
Electrochemistry
Extracellular Polymeric Substance Matrix*
Water*

Substances

Water