Insight Into Impacts of Sewage Discharge and River Self-Purification on Microbial Dynamics and Pathogenicity in River Ecosystem

Abstract

Sewage directly discharge causes serious environmental problems. Here, the effects of treated and untreated sewage on the river ecosystem were investigated. The variations of microbial community structure, including infectious pathogenic bacteria and functional bacteria related to nitrogen, phosphorus, and COD metabolism were studied in detail. Bacterial diversity and richness were significantly decreased, while, Proteobacteria containing various infectious pathogens, such as Vibrio and Helicobacter, significantly increased after the discharge of raw sewage. Although the microbial structure was slightly restored and the abundance of most pathogenic bacteria was also slightly reduced through river self-purification, direct discharge of raw sewage caused severe and short-term irreversible damage to the river environment. Direct discharge also introduced various pollutants such as nitrogen, phosphorus, and COD, increasing the corresponding functional bacteria and their related genes. Furthermore, the high abundance of pathogenic bacteria of the drain outlet was mainly from raw sewage rather than bacteria reproduction caused by water deterioration according to the RDA analysis. With these results, direct discharge disturbed the ecological balance of the river. Therefore, more attention is needed to provide a hygienic situation for people and all sewage should be treated properly. In conclusion, all sewage should be treated properly before discharge into ecosystems to mitigate its negative impacts on receiving water bodies.

Effects of Prometryn Exposure on Hepatopancreas Oxidative Stress and Intestinal Flora in Eriocheir sinensis (Crustacea: Decapoda)

“…At the genus level, we found that prometryn significantly increased the abundance of Zoogloea and a Firmicutes bacterium ZOR0006 but decreased the abundance of Shewanella in all exposure groups. Zoogloea has been reported to have multifunctional metabolic capabilities, including effects such as influencing the secretion of extracellular polymeric substances (EPS) [78]. The Firmicutes bacterium ZOR0006 belongs to the family Erysipelotrichaceae and is thought to be associated with metabolic disorders and inflammatory diseases in the host [79,80], which were indeed found to be significantly associated with hepatopancreatic immunity and inflammation in Pearson correlation analysis.…”

Methods to alleviate the inhibition of sludge anaerobic digestion by emerging contaminants: a review

“…Industrialization has resulted in a significant deterioration in the integrity of the water resources as a result of unmanaged wastewater disposal from industrial operations such as mining, pharmaceuticals, and textile (Ali et al 2017;Xie et al 2022). Industrial activities contribute a range of inorganic and organic contaminants to water systems, altering the water quality upon which biological life relies (Azzam and Tawfik 2015).…”

“…Sewage sludge or biosolids are organic and inorganic compounds produced by the biological activity of microbes in wastewater treatment plants Xie et al 2022). The production of biosolids has grown in recent decades as a result of the use of aerobic methods in sewage treatment, such as the activated sludge process (Abdul et al 2022b;Tawfik et al 2022a).…”