Physicochemical and Biological Effects on Activated Sludge Performance and Activity Recovery of Damaged Sludge by Exposure to CeO2 Nanoparticles in Sequencing Batch Reactors

Abstract

Recently, the growing release of CeO2 nanoparticles (CeO2 NPs) into sewage systems has attracted great concern. Several studies have extensively explored CeO2 NPs’ potential adverse impacts on wastewater treatment plants; however, the impaired activated sludge recovery potentials have seldom been addressed to date. To explore the physicochemical and biological effects on the activated sludge performance and activity recovery of damaged sludge by exposure to CeO2 NPs in sequencing batch reactors (SBRs), four reactors and multiple indicators including water quality, key enzymes, microbial metabolites, the microbial community structure and toxicity were used. Results showed that 10-week exposure to higher CeO2 NP concentration (1, 10 mg/L) resulted in a sharp decrease in nitrogen and phosphorus removal efficiencies, which were consistent with the tendencies of key enzymes. Meanwhile, CeO2 NPs at concentrations of 0.1, 1, and 10 mg/L decreased the secretion of tightly bound extracellular polymeric substances to 0.13%, 3.14%, and 28.60%, respectively, compared to the control. In addition, two-week recovery period assays revealed that the functional bacteria Proteobacteria, Nitrospirae and Planctomycetes recovered slightly at the phyla level, as analyzed through high-throughput sequencing, which was consistent with the small amount of improvement of the effluent performance of the system. This reflected the small possibility of the activity recovery of damaged sludge.

Activated Sludge Microbial Community and Treatment Performance of Wastewater Treatment Plants in Industrial and Municipal Zones

“…Activated sludge (AS) processes are the most widely used biological processes in wastewater treatment plants (WWTPs) worldwide, and they have been employed for pollutant removal for more than a century, owing to their high nutrient removal, toxin degradation, and biomass retention capabilities [1][2][3]. Microbial community structure and diversity affect the performance and functional stability of WWTPs [4][5][6]. Therefore, knowledge of AS microbial community structure and microbial functions will facilitate sludge population optimization and improve WWTP operation.…”

The effect of “Fishery-PV Integration” on Penaeus monodon culture and research on the micro-ecological environment

“…Water quality data indicate that levels of ammonia nitrogen, nitrite, and nitrate show consistent trends during the breeding period, with maximum values reached between 65 and 85 d, and may be related to increased food intake and excretion of shrimp in the later period of farming . Additionally, more nitrifying and denitrifying bacteria were identified in water and effluent, including Nisaea denitrificans (Urios et al, 2008), Halomonas (Wang and Shao, 2021), Nitrospira (Zhang C. et al, 2014), Dechloromonas denitrificans and Planctomyces (Feng et al, 2019), which all play a role in the nitrogen removal process. Therefore, the enrichment of nitrogen-removing bacteria may be one of the reasons for the rapid decline of the average contents of ammonia, nitrite, and nitrate in the later cultured period.…”

The effect of “Fishery-PV Integration” on Penaeus monodon culture and Micro-ecological environment

“…Halomonas (Wang, et al, 2021), Nitrospira (Zhang, et al, 2014), Dechloromonas denitrificans and Planctomyces (Feng, et al, 2019), etc., which all play a role in the nitrogen fixation process.…”