UF+RO Integrated Membrane-Based Advanced Treatment System
Principle · Process Flow · Application Fields
I. Working Principle
This system employs ultrafiltration (UF) as a pre-treatment unit for reverse osmosis (RO), leveraging the physical screening capability of PVDF hollow-fiber membranes to initially remove suspended solids, colloids, bacteria, and microorganisms from the raw water, thereby significantly reducing the SDI (Pollution Index) to ≤3 and providing clean, stable feedwater for the RO process; subsequently, under pressure-driven conditions, the RO unit performs deep desalination, retaining over 98% of dissolved salts, organic matter, and microorganisms, thereby producing desalinated water that meets regulatory standards.
The core philosophy of UF pre-treatment is "addressing pollution at its source": ultrafiltration first ensures that the water quality entering the reverse osmosis system is stable and controllable, thereby significantly extending the service life of the RO membranes, reducing the frequency of chemical cleaning, and lowering overall operating costs. The coordinated operation of the two-stage membrane system not only guarantees the quality of the product water but also enables cost-effective advanced water treatment.
• Ultrafiltration pre-treatment: removes suspended solids, colloids, and bacteria; reduces the SDI pollution index.
• Reverse osmosis desalination: achieves deep desalination under pressure-driven conditions, retaining dissolved salts and organic matter.
• Synergistic benefits: Significantly extends the service life of RO membranes and reduces operating and maintenance costs
II. Process Flow
The system is divided into three major functional sections – the ultrafiltration pretreatment section, the reverse osmosis desalination section, and the product water distribution section – from raw water intake to product water distribution.
Raw water → Raw water tank → Raw water booster pump → UF ultrafiltration unit (automatic backwashing)
↓ (UF treated water, SDI ≤ 3)
UF water storage tank → RO high-pressure pump → RO reverse osmosis system (automatic flushing)
↓ (RO treated water; desalination rate ≥ 98%)
RO treated water tank → Distribution pump (constant pressure) → Water usage point
① Ultrafiltration (UF) Pre-treatment Section
The raw water is buffered in a raw water storage tank before being pumped by a booster pump into the ultrafiltration unit. The PVDF hollow-fiber ultrafiltration membrane retains suspended solids, colloids, bacteria, and microorganisms, while reducing the SDI value to ≤3, thereby providing clean feed water for the RO process; the system performs automatic backwashing based on time or pressure differential to maintain membrane flux and operational stability.
② Reverse Osmosis (RO) desalination stage
The UF treated water is pressurized by a high-pressure pump and then fed into the RO membrane stack, where it undergoes deep desalination under pressure, retaining over 98% of dissolved salts, organic matter, and microorganisms; the resulting water is stored in the RO product water tank. The system is equipped with an automatic low-pressure flushing function upon startup and shutdown to mitigate concentration polarization and membrane fouling.
③ Water Distribution Section
The RO 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 concentrated water is either discharged in compliance with regulatory standards or reused. 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 conductivity.
III. Application Areas
This system is designed to meet the demand for advanced membrane-based treatment and desalination across various application scenarios, including municipal, industrial, and resource recovery applications; it is primarily deployed in the following fields:
• Surface water treatment: Purification and desalination pretreatment for surface water sources such as rivers, lakes, and reservoirs
• Wastewater resource recovery and reuse: reclaimed water reuse, advanced treatment and reuse of industrial wastewater
• Municipal water advanced treatment: upgrading municipal water supply systems and advanced purification of drinking water
• Industrial Park Water Supply: Centralized water supply for industrial parks and production-grade purified water preparation
• Seawater desalination pretreatment: The seawater desalination system incorporates a pre-treatment ultrafiltration stage to ensure the quality of the feed water for the RO process.
Function
