Shock load effects on WWTP performance under low loads following capacity expansion for combined sewer overflow control
Expanding wastewater treatment plant (WWTP) capacity is an effective approach to control combined sewer overflow. However, this often leads to low-load operation in dry weather and sudden peak flow during rainfall, with limited research on their impacts on WWTP performance. In this study, the design...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-04-01
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| Series: | Desalination and Water Treatment |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1944398625001638 |
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| author | Xiaomeng Han Tianyue Yu Weigang Wang Shihu Shu Yanping Zhu Hui Li Caihao Hu |
| author_facet | Xiaomeng Han Tianyue Yu Weigang Wang Shihu Shu Yanping Zhu Hui Li Caihao Hu |
| author_sort | Xiaomeng Han |
| collection | DOAJ |
| description | Expanding wastewater treatment plant (WWTP) capacity is an effective approach to control combined sewer overflow. However, this often leads to low-load operation in dry weather and sudden peak flow during rainfall, with limited research on their impacts on WWTP performance. In this study, the design capacity of pilot-scale anaerobic-anoxic-oxic reactors was same as the peak flow, while the actual inflow rate was 70 % and 50 % of the design capacity in Reactor 1 (R1) and Reactor 2 (R2), respectively. After a period of operation, the influent flow was increased to 100 % of design capacity following rainfall. Results showed R1 maintained stable pollutant removal, sludge characteristics, and bacterial community structure, showing resilience to shock load. Nevertheless, R2 experienced reduced COD, NH4+-N and TN removal efficiency, along with fluctuations in sludge concentration, activity, floc size, soluble microbial products (SMP), and extracellular polymeric substances (EPS). The bacterial communities associated with pollutant removal, filamentous bacteria, and EPS synthesis underwent significant changes, which might contribute to the performance difference. These findings highlight the importance of maintaining operational flows at no less than 70 % of peak flow to ensure stability under shock load. Operating at 50 % capacity may reduce resilience to the peak flow induced by rainfall. |
| format | Article |
| id | doaj-art-86cbafcd6b9c45219be817d976529675 |
| institution | OA Journals |
| issn | 1944-3986 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Desalination and Water Treatment |
| spelling | doaj-art-86cbafcd6b9c45219be817d9765296752025-08-20T02:32:04ZengElsevierDesalination and Water Treatment1944-39862025-04-0132210114710.1016/j.dwt.2025.101147Shock load effects on WWTP performance under low loads following capacity expansion for combined sewer overflow controlXiaomeng Han0Tianyue Yu1Weigang Wang2Shihu Shu3Yanping Zhu4Hui Li5Caihao Hu6College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Shanghai Urban Water Resources Development and Utilization National Engineering Center Co. Ltd., Shanghai 200082, ChinaCollege of Environmental Science and Engineering, Donghua University, Shanghai 201620, ChinaCollege of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Correspondence to: No. 2999 North Renmin Road, Shanghai 201620, China.College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Correspondence to: No. 2999 North Renmin Road, Shanghai 201620, China.College of Environmental Science and Engineering, Donghua University, Shanghai 201620, ChinaCollege of Environmental Science and Engineering, Donghua University, Shanghai 201620, ChinaCollege of Environmental Science and Engineering, Donghua University, Shanghai 201620, ChinaExpanding wastewater treatment plant (WWTP) capacity is an effective approach to control combined sewer overflow. However, this often leads to low-load operation in dry weather and sudden peak flow during rainfall, with limited research on their impacts on WWTP performance. In this study, the design capacity of pilot-scale anaerobic-anoxic-oxic reactors was same as the peak flow, while the actual inflow rate was 70 % and 50 % of the design capacity in Reactor 1 (R1) and Reactor 2 (R2), respectively. After a period of operation, the influent flow was increased to 100 % of design capacity following rainfall. Results showed R1 maintained stable pollutant removal, sludge characteristics, and bacterial community structure, showing resilience to shock load. Nevertheless, R2 experienced reduced COD, NH4+-N and TN removal efficiency, along with fluctuations in sludge concentration, activity, floc size, soluble microbial products (SMP), and extracellular polymeric substances (EPS). The bacterial communities associated with pollutant removal, filamentous bacteria, and EPS synthesis underwent significant changes, which might contribute to the performance difference. These findings highlight the importance of maintaining operational flows at no less than 70 % of peak flow to ensure stability under shock load. Operating at 50 % capacity may reduce resilience to the peak flow induced by rainfall.http://www.sciencedirect.com/science/article/pii/S1944398625001638Wastewater treatment plantLow loadInfluent shock loadResilienceSludge characteristicsBacterial community |
| spellingShingle | Xiaomeng Han Tianyue Yu Weigang Wang Shihu Shu Yanping Zhu Hui Li Caihao Hu Shock load effects on WWTP performance under low loads following capacity expansion for combined sewer overflow control Desalination and Water Treatment Wastewater treatment plant Low load Influent shock load Resilience Sludge characteristics Bacterial community |
| title | Shock load effects on WWTP performance under low loads following capacity expansion for combined sewer overflow control |
| title_full | Shock load effects on WWTP performance under low loads following capacity expansion for combined sewer overflow control |
| title_fullStr | Shock load effects on WWTP performance under low loads following capacity expansion for combined sewer overflow control |
| title_full_unstemmed | Shock load effects on WWTP performance under low loads following capacity expansion for combined sewer overflow control |
| title_short | Shock load effects on WWTP performance under low loads following capacity expansion for combined sewer overflow control |
| title_sort | shock load effects on wwtp performance under low loads following capacity expansion for combined sewer overflow control |
| topic | Wastewater treatment plant Low load Influent shock load Resilience Sludge characteristics Bacterial community |
| url | http://www.sciencedirect.com/science/article/pii/S1944398625001638 |
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