Under-loaded operation of an anaerobic-anoxic-aerobic system in dry and wet weather dynamics to prevent overflow pollution: Impacts on process performance and microbial community. (May 2023)

• Record Type: Journal Article
• Authors: Jiang, Lu-Man; Zhang, Zhenjian; Li, Yunhui; Xu, Jialei; Wang, Kun; Ding, Xinya; He, Junli; Qiu, Zhan; Zhou, Hua; Zhou, Zhen
• Is Part Of: Bioresource technology. Volume 376(2023)
• Publication Date: 2023-05
• Subjects: Wastewater treatment -- Hydraulic loading rate -- Wet weather -- Nutrients removal -- Microbial community; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2023.128837
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: We studied under-loaded performance of a full-scale WWTP to control overflow. Long-term under-load of WWTPs didn't affect pollutant removal and shock resistance. Under-loaded operation enlarged flocs size with overgrowth of filamentous bacteria. Under-loaded operation slightly worsened sludge settleability and floc aggregation. A remarkable increase in Thuricola confirmed the risk of flocs disintegration. Abstract: Effects of low hydraulic loading rate (HLR) in dry weather and high HLR in wet weather on pollutant removal, microbial community, and sludge properties of a full-scale wastewater treatment plant (WWTP) were extensively studied to explore the risk of under-loaded operation for overflow pollution control. Long-term low HLR operation had an insignificant effect on the pollutant removal performance of the full-scale WWTP, and the system could withstand high-load shocks in wet weather. Low HLR resulted in higher oxygen and nitrate uptake rate due to the storage mechanism under the alternating feast/famine condition, and lower nitrifying rate. Low HLR operation enlarged particle size, deteriorated floc aggregation and sludge settleability, and reduced sludge viscosity due to the overgrowth of filamentous bacteria and inhibition of floc-forming bacteria. The remarkable increase in Thuricola and the contract morphology of Vorticella in microfauna observation confirmed the risk of flocs disintegration in low HLR operation.