WANGBo-wen,MAHua-ji,PANHui,et al.Optimization of Operation Mode of Modified Step Feed-Multistage A/O System for Sewage Treatment[J].China Water & Wastewater,2025,41(5):8-17.
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Optimization of Operation Mode of Modified Step Feed-Multistage A/O System for Sewage Treatment

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第41卷 Number: 第5期 Page: 8-17 Column: Date of publication: 2025-03-01
Author(s):
WANG　Bo-wen1; 2;  MA　Hua-ji1; 2;  PAN　Hui3;  WANG　Yan-ning1; 2;  ZHANG　Shi-ze1; 2;  YUAN　Hong-ying1; 2;  MU　Rong1; 2;  ZHANG　Ran1; 2
（1. Tianjin Key Laboratory of Aquatic Science and Technology， School of Environmental and Municipal Engineering， Tianjin Chengjian University， Tianjin 300384， China； 2. Municipal Experimental Teaching Demonstration Center of Environmental and Municipal Engineering，Tianjin Chengjian University， Tianjin 300384， China； 3. Department of Architecture and Civil Engineering， Hebei Construction Material Vocational and Technical College， Qinhuangdao 066000， China）
Keywords:
step feed-multistage A/O process;  nitrogen and phosphorus removal;  settleability;  bioactivity;  mass balance
Abstract:
The bench-scale modified step feed-multistage A/O system was set up to treat synthetic sewage. It was operated successively with three-stage mode and two-stage mode. The process performance, settleability and bioactivity of activated sludge, and mass balance of process system under optimized operation mode were investigated. The results showed that the effluent water quality under two-stage mode could stably met the requirements of class I-A in GB 18918-2002. The removal efficiencies of TN and TP under two-stage mode were 82.80% and 92.98%, respectively. They were both higher than those under three-stage mode. The settleability of activated sludge was desirable. The average sludge settling volume (SV) and sludge volume index (SVI) were 36.80% and 80.74 mL/g, respectively. There was no filamentous bulking. While the filamentous bulking arose easily under three-stage mode, which could result in the operation failure. The bioactivity of activated sludge under two?stage mode was higher than that under three-stage mode. The specific phosphorus release rate, specific denitrification rate, specific nitrification rate, and specific phosphorus uptake rate were 0.77 mg/(g·h), 3.99 mg/(g·h), 1.12 mg/(g·h), and 0.21 mg/(g·h), respectively. They were 1.33 times, 4.56 times, 1.30 times, and 1.90 times of those under three-stage mode. Compared with three-stage mode, the two-stage mode was desirable for the modified step feed-multistage A/O system. The balances of COD, nitrogen and phosphorus were 93.81%, 97.79% and 83.77%, respectively. The carbon sources consumed for nitrogen removal was 5.25 g/g, and it was 4.12 g/g for the first stage and 6.65 g/g for the second stage. The carbon sources consumed for phosphorus removal was 11.29 g/g.
Last Update: 2025-03-01