WangXinyu,ShenLiqing,LuChangyu,et al.Pilot-scale Study on CO2 Addition for Coagulation Optimization and Aluminum Control[J].China Water & Wastewater,2026,42(17):67-72.
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Pilot-scale Study on CO2 Addition for Coagulation Optimization and Aluminum Control

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第42卷 Number: 第17期 Page: 67-72 Column: Date of publication: 2026-09-01
Author(s):
Wang　Xinyu1;  Shen　Liqing2;  Lu　Changyu1;  Lin　Wei3;  Hao　Xinli1;  Fan　Juhong3
（1. Hebei Province Key Laboratory of Sustained Utilization & Development of Water Resources， School of Water Resource and Environment， Hebei GEO University， Shijiazhuang 052160， China； 2. Tongxiang Water Affairs Group Co. Ltd.， Tongxiang 314502， China； 3. Yangtze Delta Region Institute of Tsinghua University Zhejiang， Jiaxing 314022， China）
Keywords:
carbon dioxide;  pH;  aluminum control;  coagulation
Abstract:
To address the challenge of significantly reduced coagulation efficiency caused by wetland source water temperatures exceeding 30 ℃ and pH greater than 7.8 in summer, a method of replacing traditional polyaluminum chloride (PAC) pH adjustment with carbon dioxide (CO2) pretreatment for aluminum control was proposed, and its underlying mechanism for improving coagulation performance was investigated. The results showed that CO2 pretreatment could precisely regulate the raw water pH to 7.2. Under this condition, the residual aluminum concentration in the effluent of the V-type filter remained consistently below 0.02 mg/L, while the removal rates of total suspended solids (TSS), dissolved organic carbon (DOC), and permanganate index were significantly enhanced. Floc characterization and Zeta potential measurements revealed that after CO2 addition, the average floc particle size increased and the floc structure became denser, accompanied by a rise in Zeta potential. These findings indicated that the coagulation process was optimized through enhanced charge neutralization and improved floc compactness.
Last Update: 2026-09-01