Water purification system is used in the field of food & beverage production, pharmaceutical and electronics industry and so on. For different industries, the removal accuracy of the pollutants in water is different. But the common requirement of their needed water is that the most part of impurities are removed except water molecule. The main devices in a water purification system are listed below:
System of water purification is very important to our daily life. For every industry which needs the pure water, daily maintenance is essential to the overall water purification system’s normal operation. When the installation and commissioning processes are completed, knowing about the proper daily maintenance is crucial to the lifespan of purification system, so do the same to system operating efficiency and product water quality. Daily maintenance mainly refers to the maintenance of pretreatment devices, RO system and downtime maintenance.
Proper maintenance of pretreatment devices optimizes the operation of RO purification system.
1) For the sand filter and activated carbon filter in pretreatment, the backwash period is determined by the quality of raw water. If the raw water is clean tap water, the routine backwash period is about a week. If the feed water is underground water, or the water from river and well, the period is about 3 days. The backwash process makes sure that the accumulated sludge, impurities and particles in pretreatment devices can discharge in time.
2) In order to guarantee the inlet water quality of RO device, the filter element of security filter must be replaced when differential pressure of inlet and outlet water exceeds 0.06 Mpa. The replacement period of filter element is determined by inlet water quality, and the average replacement period is 2-3 months.
3) Soften resin tank should be avoid sun exposure.
Proper maintenance of RO system affects quality of outlet water of purification system.
1) Routine record must be done for all the operating parameters of RO device. It suggests that record should be done once for every 2 hours.
2) RO membrane element needs periodic cleaning. The accumulated sediments on the surface of RO membrane affects membrane permeable capacity. For different causes, equivalent cleaning measurement can be adopted according to Chemical Cleaning Methods of RO Membrane.
Whatever one of the following conditions, membrane element should be cleaned: Normal output flow declines 10%; Salt content in water production obviously increases; Each pressure difference of RO device increases by 15% or 35kPa compared to initial running period. It is verified that there is pollution or scaling; Even though pressure difference does not increase by 15%, it has run for 3~4 months; Conduct cleaning before stopping operating due to it needs stopping running for long time.
3) Routine inspection to conductivity gauge, various pressure gauge and PLC system, maintaining normal operation of RO system.
4) Periodic inspection to the raw water pump and high pressure pump, and replace lubricating oil in time according to the maintenance manual.
Proper downtime maintenance prolongs the lifespan of water purification system.
1) For short-term downtime of RO device ( less than 3 days), the purification system should be flushing once for every 24 hours , and the filtered water should be filled in RO membrane module.
2) For a long-term downtime of RO device (over 3 days), formaldehyde solution with 1% concentration should be full filled in RO membrane module. All the valves should be shut down and inspected once per month. Mildew should be prevented by controlling the environmental temperature in summer, and antifreezing should be done by adding 10-20% glycerinum into the formaldehyde solution in winter.
3)It is better to use outlet fresh water of RO device as the preserving water of system, and formaldehyde solution should be chemical reagent product.
4) When the RO membrane is composite type and the downtime period is more than a week, the RO membrane should be submerged in NaHSO3 solution with 1% concentration in order to prevent bacterial reproduction on the surface of membrane.
The maintenance of water purification system is a scrupulous process. When you do it properly, the system of water purification can get maximized production efficiency and less cost.