Application of 3-Free Direct Filtration Technology in Water Treatment Projects at Coal-Fired Power Plants

Release time:

2026-04-09

The All-Without-Components Direct Filtration (ASSFBR) technology, with its three core features—no power requirement, no consumables, and shock resistance—has emerged as a highly efficient water-treatment solution for coal-fired power plants, primarily deployed in four key application scenarios.

　　The All-Without-Components Direct Filtration (ASSFBR) technology, with its three core features—no power requirement, no consumables, and shock resistance—has emerged as a highly efficient water-treatment solution for coal-fired power plants, primarily deployed in four key application scenarios.

　　1. Reuse and Resource Recovery of Coal Slurry Water (Core Application Scenario)

　　- Application scenarios: coal slurry water with high suspended solids (SS up to several thousand mg/L), such as flushing water in coal-handling systems, spray-water for coal yards, and coal-washing wastewater.

　　-Process flow: a skid-mounted integrated system for front-end coagulation followed by three-stage direct filtration and advanced treatment, utilizing plant-site residual pressure or liquid-level differences to enable gravity-flow filtration.

　　- Core performance: Effluent SS consistently below 5 mg/L, meeting reuse standards; the coal fines recovered during backwashing can be directly returned to the coal yard, enabling resource recycling; no consumable replacements are required, significantly reducing operation and maintenance costs.

　　- Project examples: The coal-washing wastewater treatment and reuse project at the Guangzhou Nansha Thermal Power Plant and the Wenzhou China Resources Thermal Power Plant has been successfully implemented.

　　Power plant.jpg

　　2. Advanced Treatment of Recycled Water Wastewater

　　- Application scenario: Wastewater from recirculating cooling water systems, characterized by high salinity (TDS 1500–5000 mg/L), high hardness, the presence of corrosion and scale inhibitors, and a certain level of suspended solids.

　　-Process flow: Direct filtration serves as the core pretreatment unit, replacing the conventional “coagulation–sedimentation + ultrafiltration” process, thereby ensuring that the effluent SDI is less than 3 and meets the feedwater requirements for RO reverse osmosis.

　　- Core advantages: Passive operation reduces energy consumption, exhibits excellent resistance to high-hardness fouling, and prevents clogging common in conventional membrane systems; can be used as makeup water for recirculating cooling water or as pretreatment for boiler feedwater, thereby increasing the concentration factor.

　　3. Preliminary Treatment of Comprehensive Wastewater from Power Plants

　　- Application scenario: Mixed wastewater from plant-site domestic sewage, chemical cleaning effluent, desulfurization wastewater, etc., characterized by significant water-quality fluctuations and complex compositional profiles.

　　-Process route: Used as a front-end pretreatment step for biochemical systems (such as MBR and activated sludge processes), or as a pre-treatment unit prior to RO-based desalination.

　　- Core benefits: highly efficient removal of suspended solids and colloids, ensuring stable influent water quality; excellent resistance to high-load shocks, eliminating the need for frequent parameter adjustments and protecting downstream biochemical and membrane systems.

　　4. Pre-treatment for Zero Liquid Discharge of High-Salinity Wastewater

　　- Application scenarios: High-salinity wastewater such as flue-gas desulfurization effluent from power plants and boiler blowdown, which requires zero discharge.

　　-Process flow: a combined system of direct filtration, softening, and nanofiltration/reverse osmosis, serving as the core pretreatment unit for the zero-discharge system.

　　- Core advantages: low-cost removal of suspended solids, reducing the risk of scaling in downstream evaporation and crystallization systems; no consumable losses; compatibility with high-salinity feedwater; and enhanced overall stability of zero-discharge systems.

　　Core technological advantages tailored to power plant needs

　　1. Power-free water production: Utilizes the plant’s elevation head or residual pressure for gravity filtration, eliminating the need for additional booster pumps and significantly reducing energy consumption at high flow rates.

　　2. No consumable replacements: Utilizing a permanent filter column, combined air–water backwashing restores filtration capacity, eliminates solid waste generation, and reduces annual operation and maintenance costs by more than 80%.

　　3. Strong shock resistance: The system maintains stable operation even when influent SS levels fluctuate, ensuring that effluent quality meets standards and accommodating the variable operating conditions typical of power plants.

　　4. Space-saving and highly efficient: The skid-mounted design reduces the footprint to only 1/3 to 1/2 that of a conventional sedimentation tank, making it ideal for plant expansion and renovation.

　　Summary of Application Value

　　The “three-no” direct filtration technology delivers dual value—water conservation, energy efficiency, cost reduction, and resource recovery—by precisely addressing the pain points of water treatment in coal-fired power plants, and its feasibility has been validated in multiple plant projects. Its core value lies in:

　　- Achieve a high rate of reuse for coal slurry water, circulating water, and wastewater, thereby reducing fresh water consumption;

　　- Replaces traditional high-cost processes, reducing water treatment costs to as low as RMB 0.023 per ton and significantly lowering plant electricity consumption and O&M expenses;

　　- Assist power plants in achieving “zero emissions” and clean production, and enhance the level of resource recycling.

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