As the core component of water‑treatment systems, ultrafiltration units are widely applied in purified‑water production, reclaimed‑water reuse and industrial pure‑water preparation.
When the equipment runs continuously for a long time, faults frequently occur due to improper installation, membrane fouling, worn‑out fittings and incorrect operation. These issues lower water‑production efficiency, worsen water quality, raise maintenance costs and shorten the service life of ultrafiltration membranes.
Most maintenance workers struggle to find root causes quickly once abnormalities happen.
Today we list seven frequent failures of ultrafiltration systems with accurate cause analysis and practical solutions. Even new‑comers can finish troubleshooting efficiently.
Ⅰ. Equipment Water Leakage
Leaks mostly appear at flanges, pipe joints and sealing areas. Minor leakage wastes water resources. Severe leakage disturbs operating pressure and brings about secondary failures.
✅ Causes and Solutions
1.Improper component installation
Pipes and connectors are mis‑aligned and poorly fitted.
Take parts apart and reinstall them in proper positions to guarantee tight fitting.
2.Loose flange bolts
Machine‑produced vibration loosens bolts and widens sealing gaps.
Tighten flange bolts evenly in a diagonal sequence to stop leakage caused by uneven stress.
3.Aged or damaged gaskets
Long‑term compression and water‑quality‑related corrosion deform and break gaskets.
Disassemble joints, fit new gaskets of the same size and reassemble all parts.
Ⅱ. Low Permeate Flow‑Rate
If the produced‑water flow falls below the designed value, the overall water‑treatment capacity will drop and fail to meet production‑water requirements.
✅ Causes and Solutions
1.Abnormal inlet‑outlet pipelines
Valves are partly closed, pipes are bent or blocked by impurities.
Inspect all pipeline valves fully. Open valves completely, clear blockages and repair deformed pipes.
2.Flow‑meter malfunction
Dirty probes or damaged instruments give false low‑flow readings.
Clean flow‑meter probes and check instrument performance. Replace the device if faults cannot be fixed.
3.Fouled ultrafiltration membranes
Sediment, colloids and microorganisms build‑up and block membrane pores.
Carry out back‑washing or intensive chemical cleaning based on fouling levels to restore membrane permeability.
Ⅲ. Excessively High Operating Trans‑membrane Pressure
Exceeded transmembrane pressure serves as a key sign of membrane fouling and abnormal settings. Long‑term high‑pressure operation speeds up fiber ageing of ultrafiltration membranes.
✅ Causes and Solutions
1.Severe ultrafiltration‑membrane fouling
Built‑up pollutants increase water‑flow resistance.
Apply chemical backwashing for light fouling and professional chemical cleaning for heavy fouling.
2.Pressure gauge malfunction
Faulty instruments show inaccurate readings and create false high‑pressure data.
Calibrate the pressure gauge and install a new one once it gets damaged.
3.Over‑high permeate flow rate
Over‑loaded operation leads to sharp pressure‑difference rise.
Adjust operating parameters and keep the water output within the designed range.
Ⅳ. Sub‑Standard Permeate Water Quality
Excessive turbidity and contaminants in output water mainly come from three factors: poor raw‑water quality, faulty membrane modules and testing errors.
✅ Causes and Solutions
1.Unqualified raw‑water quality
Sudden rise of turbidity and excessive impurities overload the system.
Switch to qualified water sources or install pre‑treatment units upfront to reduce raw‑water turbidity.
2.Fouled and ineffective ultrafiltration membranes
Blocked pores weaken its filtering capacity.
Carry out chemical cleaning and backwashing to remove surface dirt and restore filtration performance.
3.Measurement errors
Uncalibrated meters and improper operations produce false results.
Calibrate testing instruments regularly and standardize operating steps to avoid human‑caused deviations.
4.Broken membrane fibers
High‑pressure operation, aging and external damage break fibers. Raw water leaks directly and pollutes produced water.
Find broken fibers by air‑tightness tests and block them. Replace the whole membrane module if fiber damage is serious.
Ⅴ. Low Backwash Flow Rate
Insufficient back‑wash flow fails to thoroughly wash away pollutants on membrane surfaces. Long‑term buildup worsens membrane fouling and greatly shortens membrane service life.
✅ Causes and Solutions
1.Abnormal backwash pipelines
Partially‑opened valves and scale buildup block pipelines.
Inspect and fully open control valves, then thoroughly clear debris and scale inside pipes.
2.Inadequate water supply from the back‑wash pump
Pump blockage, damaged impellers, cavitation and partly‑opened valves are common issues.
Open valves fully, clear dirt inside the pump, repair impellers and adjust working conditions to eliminate cavitation. Replace parts if needed.
3.Abnormal readings of the flow meter
Blocked probes and instrument breakdown lead to incorrect data.
Clean probes and test the meter. Replace it when repairs prove ineffective.
4.Fouled ultrafiltration membranes
Clogged membrane pores hold back back‑wash water flow.
Perform chemical backwashing or intensive cleaning to unclog pores and recover flow‑rate.
Ⅵ. Excessively High Backwash Pressure Difference
Excessive backwash pressure difference indicates abnormal working conditions. It not only fails to clean membrane elements but also may damage ultrafiltration membranes and trigger equipment breakdowns.
✅ Causes and Solutions
1.Fouled ultrafiltration membranes
Stubborn contaminants raise resistance against back‑wash water flow.
Remove pollutants thoroughly by chemical backwashing and intensive deep‑driven cleaning.
2.Failed pressure gauge
Deviated readings and damaged instruments lead to falsely high pressure‑difference values.
Calibrate the gauge and replace it right away once damaged.
3.Over‑high backwash flow rate
Over‑loaded backwash causes a sharp rise in pressure difference.
Adjust parameters and keep back‑wash flow within the equipment’s designed range.
Ⅶ. Valve Failures
Valves serve as core automatic‑control parts for the whole set‑up. Valve breakdowns cause improper pipeline switching and bring about chain‑reaction problems regarding flow rate and pressure difference.
✅ Causes and Solutions
1.Insufficient air‑supply pressure (for pneumatic valves)
Low air pressure and air‑leaking pipelines prevent valves from fully opening or closing.
Adjust air‑supply pressure to its rated value, find and fix leakage points to stabilize the air‑supply system.
2.Valve feedback malfunction
Failed feedback transmitters and abnormal signals stop the system from detecting valve status.
Check wiring and components of feedback transmitters. Replace them in case of severe damage.
3.Mechanical failures inside valves
Stuck valve stems, worn‑out valve cores and aging parts occur frequently.
Test valve operation manually and clear blocking debris. Install a brand‑new valve if repairs do not work.
???? Maintenance Summary
Most faults of ultrafiltration equipment arise from four main factors: inadequate maintenance, out‑of‑range parameters, aging fittings and pipeline blockage.
Regular inspections, instrument calibration, membrane cleaning and component maintenance in daily use will greatly cut costs and improve working efficiency.
When abnormalities occur, refer to this fault checklist for quick troubleshooting so as to ensure steady and long‑term equipment operation.
