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Enhanced coagulation for high alkalinity and micro-polluted water: the third way through coagulant optimization
Mingquan Yan1, Dongsheng Wang, Jiuhui Qu
1Department of Environmental Engineering, College of Environmental Science and Technology, The Key Laboratory of Water and Sediment Sciences, MOE, Peking University, Beijing, China. Yankingcn@yahoo.com
Water Research
|January 22, 2008
Summary
A novel composite polyaluminum chloride (HPAC) effectively removes natural organic matter (NOM) and turbidity in high alkalinity water. This optimized enhanced coagulation method surpasses traditional treatments, offering a cost-effective solution for water purification.
Area of Science:
- Environmental Science
- Water Treatment Technologies
- Materials Chemistry
Background:
- Conventional coagulation struggles with natural organic matter (NOM) removal in high alkalinity/pH water.
- Current enhanced coagulation methods involve water acidification or increased coagulant doses, leading to increased corrosivity and cost.
- There is a need for more efficient and cost-effective water treatment solutions for challenging water chemistries.
Purpose of the Study:
- To demonstrate an improved enhanced coagulation method using a novel coagulant for treating high alkalinity/pH water.
- To develop and evaluate a composite polyaluminum chloride (HPAC) coagulant.
- To assess the efficiency of HPAC in removing dissolved organic carbon (DOC) and turbidity.
Main Methods:
- Development of a novel composite polyaluminum chloride (HPAC) coagulant, combining polyaluminum chloride (PACl) with additive coagulant aids.
- Comparative analysis of HPAC against traditional coagulants (alum, ferric salts) for NOM and turbidity removal.
- Pilot-scale testing involving sequential water treatment steps: pre-ozonation, coagulation, flotation, and sand filtration.
Main Results:
- HPAC demonstrated 30% greater efficiency than alum and ferric salts in dissolved organic carbon (DOC) removal.
- HPAC proved highly effective in removing turbidity from water.
- Pilot-scale tests confirmed synergistic removal of particles and organic matter using HPAC in a multi-step treatment process.
Conclusions:
- The developed HPAC coagulant offers a superior and more efficient alternative for enhanced coagulation in high alkalinity/pH water.
- HPAC overcomes the limitations of traditional and current enhanced coagulation methods, reducing corrosivity and treatment costs.
- The study validates HPAC's effectiveness in a pilot-scale setting, highlighting its potential for practical water treatment applications.
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