Best Guide: The Most Common Operational Problems in Industrial RO Systems and How to Solve Them| Insights by AQUALITEK

The Most Common Operational Problems in Industrial RO Systems

1. Introduction

Industrial reverse osmosis (RO) systems are critical for producing high-purity water in sectors such as power generation, pharmaceuticals, food processing, and electronics manufacturing. However, during continuous operation, various problems can arise that reduce system efficiency, increase energy consumption, and shorten membrane lifespan. Understanding these problems and addressing them early is vital for maintaining stable operation and controlling costs.

2. Common Operational Problems

(1) Membrane Fouling

Membrane fouling is the most frequent issue in RO operation. It occurs when suspended solids, colloids, or organic matter accumulate on the membrane surface, forming a barrier that increases differential pressure and decreases permeate flow.
Causes: Inadequate pretreatment, poor filtration, or sudden feed water quality fluctuations.
Solutions:

•Install multi-media or ultrafiltration pretreatment.

•Regularly clean membranes with appropriate chemical agents.

•Monitor SDI (Silt Density Index) to ensure it remains below 5.

(2) Scaling

Scaling occurs when dissolved salts—such as calcium carbonate, calcium sulfate, or barium sulfate—exceed their solubility limits and crystallize on the membrane surface.
Causes: High feed water hardness and improper antiscalant dosing.
Solutions:

•Use acid dosing or antiscalant chemicals.

•Conduct periodic cleaning with citric acid or other scale removers.

•Maintain optimal recovery rates to avoid oversaturation.

(3) Biofouling

Biofouling results from bacterial growth and the formation of biofilms on the membrane surface or in pipelines. Once formed, biofilms are difficult to remove and can cause severe performance decline.
Causes: High organic content, stagnation, and inadequate disinfection.
Solutions:

•Pre-chlorination or UV disinfection of feed water.

•Regular sanitation with biocides.

•Maintain continuous flow to prevent microbial buildup.

(4) Organic Fouling

Organic molecules such as humic acids, oils, and surfactants can block membrane pores or reduce surface hydrophilicity, leading to reduced permeate flow.
Solutions:

•Use activated carbon filters or coagulation pretreatment.

•Periodically clean membranes with alkaline cleaning agents.

(5) Mechanical and Hydraulic Issues

Pressure fluctuations, pump failures, or improper valve control can cause vibration, water hammer, or even membrane damage.
Solutions:

•Use pressure relief valves and soft-start controllers.

•Regularly calibrate instruments and inspect pumps and pipelines.

(6) Chemical Degradation

Excessive chlorine exposure or improper cleaning chemicals can cause irreversible membrane oxidation.
Solutions:

•Ensure dechlorination using sodium bisulfite.

•Use pH-controlled cleaning agents and avoid oxidants unless specified safe by the membrane manufacturer.

3. How to Monitor and Prevent Operational Problems

An effective RO operation strategy should include:

•Online monitoring of pressure, conductivity, and flow.

•Scheduled chemical cleaning (CIP) based on normalized performance data.

•Comprehensive pretreatment combining filtration, softening, and disinfection.

•Regular performance audits to identify early signs of degradation.

4. Conclusion

Operational problems in industrial RO systems are inevitable, but with systematic monitoring, optimized pretreatment, and regular maintenance, their impacts can be minimized. Proactive management not only extends membrane lifespan but also ensures consistent water quality and lower total lifecycle costs.