General Approach

Surface water treatment for drinking compliance follows a full-process strategy: “Source Early Warning → Conventional Treatment → Advanced Treatment → Safe Disinfection → Distribution Security.” Surface water sources are susceptible to seasonal algae blooms, organic matter fluctuations, temperature variations, and sudden pollution incidents. A multi-barrier treatment process combination ensures effluent meets the Standards for Drinking Water Quality (GB 5749) requirements.

Core Technical Routes

① Source Early Warning + Emergency Pretreatment: Establish an online raw water quality early warning system equipped with powdered activated carbon (PAC) and potassium permanganate emergency dosing facilities. Enables rapid response to sudden organic pollution, algal toxins, or taste-and-odor events. Applicable to water supply systems with potential contamination risks within source water protection zones.

② Conventional Treatment Enhancement (Pre-Oxidation + Enhanced Coagulation): Pre-chlorination or ozone pre-oxidation of raw water targets algae and organic matter removal. Enhanced coagulation with increased PAC and polymer coagulant dosage improves turbidity and algal cell removal efficiency. Applicable to eutrophic lakes and reservoir sources in southern regions.

③ Advanced Treatment (Ozone-Activated Carbon + Membrane Technology): Ozone oxidation degrades organic micropollutants. Activated carbon adsorption removes taste-and-odor compounds and organics. Ultrafiltration and nanofiltration remove algae, algal toxins, and macromolecular organics. Applicable to surface water with significant quality fluctuations or trace organic contamination requiring advanced treatment.

④ Seasonal Algae-Specific Control (Air Flotation + Biological Pretreatment): Dissolved air flotation (DAF) efficiently removes algal cells. Biological pretreatment basins with ceramsite or volcanic rock media biologically oxidize ammonia nitrogen and organic matter. Applicable to eutrophic reservoirs and river sections with frequent algal blooms.

⑤ Low-Temperature and Low-Turbidity Water Treatment (Micro-Flocculation + Magnetic Loading): Under low-temperature conditions, polymer coagulants form micro-flocs. Magnetic loading accelerates flocculation and sedimentation. Applicable to northern reservoir sources with low-temperature and low-turbidity raw water during winter.

Key Considerations

The core principle of surface water treatment for drinking is “adapting to change and ensuring safety.” Surface water quality varies significantly with seasons, climate, and upstream conditions, necessitating water quality early warning mechanisms and emergency response protocols.

Southern regions should prioritize algae blooms and organic matter management. Northern regions should focus on low-temperature, low-turbidity conditions and winter ice-cover water quality challenges.

It is recommended to divide the annual operation into distinct regimes based on seasonal source water quality patterns—such as high-algae periods, low-temperature periods, wet seasons, and dry seasons—with corresponding operational strategies developed for each condition.