**Solutions for RO Membrane Blockage**

 

1. **Enhance Pretreatment**: If suspended solids, colloids, and organic matter in the water are not effectively removed, it can lead to scaling or fouling on the membrane surface. Implementing ultrafiltration pretreatment can help; for example, in a certain electronics factory where the source water SDI was 8 and not cleaned regularly, the membrane life was 14 months. After adding ultrafiltration pretreatment to reduce the SDI to 3, the membrane life was extended to 42 months. Additionally, a multimedia filter should be backwashed every 24 hours, and the activated carbon filter should be regenerated weekly.

 

2. **Control Operating Parameters**: Under standard water temperature (25°C), the operating pressure should be maintained between 1.0-1.2 MPa, and during high summer temperatures, the pressure should be reduced to 0.8 MPa (for every 1°C rise, reduce pressure by 2%). The conventional system recovery rate should be ≤75%, and for high hardness water sources, it should be reduced below 60%. Before starting, perform a low-pressure rinse (0.3 MPa) for 3-5 minutes to expel air and accumulated impurities from the membrane housing; after shutdown, rinse the membrane surface with product water for 10 minutes to prevent salt crystallization on the concentrate side (if shut down for more than 24 hours, a protective solution is needed).

 

3. **Regular Chemical Cleaning**: When the system’s product water output decreases by 15%, the desalination rate drops by 5%, or the operating pressure increases by 10%, immediate chemical cleaning is required. Before chemical cleaning, rinse with fresh water for 30 minutes to avoid reactions between the chemicals and contaminants. Different agents can be used for different pollutants; for instance, citric acid can be used to remove inorganic scales, sodium hydroxide for organic materials and microorganisms, and sodium hypochlorite as an oxidant to kill microorganisms.

 

4. **Ensure Protection in Special Scenarios**: If the system is shut down for more than 7 days, configure a 1% sodium bisulfite solution (pH 3-4) to fill the membrane housing and close all valves, replacing the protective solution every 15 days. In summer, increase the frequency of pretreatment backwashing (twice a day) to prevent high temperatures from promoting microbial growth; in winter, if the inlet water temperature is below 15°C, increase the operating pressure appropriately (not exceeding 1.3 MPa) to avoid a decrease in product water output.

 

**Reducing Equipment Maintenance Costs**

 

1. **Optimize System Design**: Use an integrated process of "pretreatment + double-stage RO + EDI" to enhance resource utilization through tri-level synergy, such as returning the second-stage RO concentrate back to the source water tank, which can increase source water utilization from 60% to 90%. Additionally, select suitable pipelines, such as 316L stainless steel electropolished pipes with an internal roughness Ra ≤ 0.5 μm, to reduce microbial attachment. Control the pipeline slope at 0.5%, and ensure the length-to-diameter ratio of branch pipes is ≤6:1 to avoid dead zones, allowing CIP cleaning cycles to be extended from once a month to once every three months, thereby reducing cleaning agent consumption.

 

2. **Adopt Intelligent Control**: Build a PLC + SCADA intelligent control system to monitor key indicators such as conductivity, TOC, and temperature online. The system can automatically alert for data anomalies and trigger rinsing or shutdown protection actions. Additionally, establish an equipment operation database that uses AI algorithms to predict the degree of RO membrane contamination and the risk of pump failures, allowing for early maintenance planning and reducing unplanned downtime by 70%. The remote monitoring feature can also save 80% of inspection manpower, enhancing operational efficiency by 50%.

 

3. **Recover Energy and Waste Heat**: Install a pressure exchange energy recovery device in the RO system to convert the residual pressure of the concentrate into driving force for the inlet water, reducing high-pressure pump energy consumption by 40%. In multi-effect distillation for injection water production, recover waste heat from the condensate using a plate heat exchanger to preheat source water to above 60°C, thus reducing steam consumption by 50% and lowering energy costs.