The cost of treating water purification plant water treatment residuals is high, with a low recovery rate and unstable effluent water quality, particularly in plants using lake and reservoir water sources in severe cold regions. Maximizing water resource utilization requires integrating water treatment residuals concentration and treatment effectively. Here, ceramic membrane technology was employed to separate supernatant and substrate after pretreatment. Optimal settling was achieved using 75 μm magnetic powder at 200 and 4 mg/L of nonionic polyacrylamide co-injection. Approximately 65% of the separated supernatant was processed by 0.1–0.2 μm Al2O3 ceramic membranes, yielding a membrane flux of 50 L/m2h and a water recovery rate of 99.8%. This resulted in removal rates of 99.3% for turbidity, 98.2% for color, and 87.7% for color and permanganate index (chemical oxygen demand, COD). Furthermore, 35% of the separated substrate underwent treatment with 0.1–0.2 μm mixed ceramic membranes of Al2O3 and SiC, achieving a membrane flux of 40 L/m2h and a water recovery rate of 73.8%. The removal rates for turbidity, color, and COD were 99.9%, 99.9%, and 82%, respectively. Overall, this process enables comprehensive concentration and treatment integration, achieving a water recovery rate of 90.7% with safe and stable effluent water quality.

Process study of ceramic membrane treatment for water treatment residuals from lake and reservoir water purification plants in severe cold regions
    Abstract
    1 Introduction
    2 Methods
        2.1 Drainage water characteristics
        2.2 Small pilot test setup
        2.3 Methods for analyzing drainage water quality
        2.4 Methods for analyzing the nature of drainage water
        2.5 Ceramic membrane performance evaluation and characterization
            2.5.1 Performance evaluation
        2.6 Ceramic membrane characterization
    3 Results and discussion
        3.1 Pretreatment process selection
            3.1.1 Inorganic flocculant dosing test
            3.1.2 Combined organic and inorganic flocculant dosing
        3.2 Ceramic membrane treatment of drainage water process research
            3.2.1 Screening of ceramic membrane types
            3.2.2 Ceramic membrane pore size screening
            3.2.3 Screening of process operating parameters
                3.2.3.1 Membrane flux screening 
        3.3 Aeration screening
        3.4 Cycle operating mode screening
    4 Conclusions
        4.1 Pretreatment experiment
        4.2 Ceramic membrane performance
        4.3 Long-cycle operation test
    References

• Tiefu Xu(School of Civil Engineering, Heilongjiang University, Harbin 150080, China)
• Yu Huang(School of Civil Engineering, Heilongjiang University, Harbin 150080, China)
• Wenfei Ye(Shanghai Investigation, Design and Research Institute Co., Ltd, Shanghai 200124, China)
• Man Wang(School of Civil Engineering, Heilongjiang University, Harbin 150080, China)
• Yuejia Chen(School of Civil Engineering, Heilongjiang University, Harbin 150080, China)
• Hong Yang(Shanghai Investigation, Design and Research Institute Co., Ltd, Shanghai 200124, China)
• Binqiao Ren(Institute of Advanced Technology, Harbin 150028, China)