I. Working Principle
This system employs hollow-fiber ultrafiltration (UF) membrane filtration technology with membrane pore sizes of 0.01–0.1 μm; utilizing a physical screening mechanism, it effectively retains suspended solids, colloids, bacteria, viruses, and large-molecule organic compounds from the water, while significantly reducing the SDI (Pollution Index) to ≤3. The system can operate as an independent water purification unit to directly produce treated water that consistently meets regulatory standards, or it can serve as a pre-treatment stage for reverse osmosis (RO) systems, providing clean and stable feed water for RO processes.
The key to the UF system lies in maintaining membrane flux and delaying membrane fouling through timed air–water backwashing and Chemical Enhanced Backwashing (CEB), thereby significantly extending the service life of the membrane modules and reducing operating and maintenance costs.
• Physical screening: 0.01–0.1 μm – captures suspended solids, colloids, bacteria, and viruses
• Stable reduction of SDI: Provides clean feedwater for subsequent processes (e.g., RO).
• Intelligent backwashing maintenance: Air–Water Backwashing + CEB – maintains permeate flux and extends membrane service life
II. Process Flow
The system is divided into three major functional sections – Pre-treatment and Pressurization Section, UF (Ultrafiltration) Main Filtration Section, and Product Water Distribution Section – with a rated water production capacity of 20,000 L/h (approximately 20 m³/h).
Raw water → Raw water storage tank → Raw water booster pump → UF ultrafiltration unit (air–water backwash + CEB)
↓ (UF treated water, SDI ≤ 3)
Water production tank → Distribution pump (constant pressure) → Water usage point
(Alternatively, can be used as pre-treatment before RO → integration into the RO system)
① Pre-treatment and Boosting Section
The raw water is buffered in a raw water tank before being pumped into the ultrafiltration unit by a booster pump, providing a stable flow rate and pressure for the UF membranes.
② UF Ultrafiltration Main Filtration Section
The hollow fiber UF membrane performs physical rejection under pressure-driven conditions, and the produced water is directed into the product water tank; the system automatically initiates an air–water backwash based on time or pressure differential, and performs a chemical enhanced backwash (CEB) at a preset interval to maintain membrane flux and rejection performance.
③ Water Distribution Section
The UF treated water is buffered in a storage tank before being delivered to all water usage points via a distribution pump operating at constant pressure; the entire system is controlled by a PLC-based interlinked control system, with real-time monitoring and interlocking mechanisms for liquid level, pressure, flow rate, and membrane pressure differential (TMP).
III. Application Areas
This system is designed to meet the membrane-based advanced treatment requirements across various application scenarios—including municipal, industrial, and resource recovery applications—and is primarily deployed in the following contexts:
• Surface water pretreatment: Purification of surface water sources such as rivers, lakes, and reservoirs
• Wastewater resource recovery and reuse: reclaimed water reuse, advanced treatment and reuse of industrial wastewater
• Swimming pool water treatment: circulating water purification and turbidity control
• Advanced drinking water treatment: Upgrading municipal water supply systems and implementing advanced drinking water purification processes
• RO System Front-End Protection: As a pre-treatment step for reverse osmosis systems, it significantly extends the service life of the RO membranes.
