Step 1: Roughing Filtration. Feed water is first pumped through a 100-150 micron auto self-cleaning strainer or disc filter. This protects the delicate hollow fibers of the skid-mounted ultrafiltration system from large debris and sharp particles that could cause mechanical damage.
Step 2: Low-Pressure Membrane Separation. The water is then pressurized to merely 1-3 bar (0.1-0.3 MPa) and forced through the high-tensile PVDF or PES hollow fiber membranes. Operating on a dead-end or cross-flow topology, the 0.03 μm pores act as an absolute physical barrier. This municipal water purification plant successfully achieves a 4-log (>99.99%) reduction of bacteria, viruses, cysts, and suspended solids without heavily relying on chemicals.
Step 3: Automated Backwash & CEB. Unlike RO, UF operates with frequent automated cleaning cycles. Every 30-60 minutes, the Siemens PLC triggers a reverse flow of clean filtrate (Backwash) combined with air scouring to dislodge particulate matter from the membrane surface. Once a day, a Chemically Enhanced Backwash (CEB) using Sodium Hypochlorite (NaOCl) and Acid/Alkali is performed to eliminate biofouling and restore Transmembrane Pressure (TMP).
Step 4: Output as Drinking Water or RO Pre-treatment. The resulting filtrate guarantees a turbidity of < 0.1 NTU. This ultra-clean water can be directly distributed as community potable water, or sent to a downstream high-pressure RO stack as the ultimate pre-treatment, massively extending the life of the RO elements.
