The new reverse osmosis membrane components are usually soaked in 1% NaHSO3 and 18% glycerol aqueous solution and stored in sealed plastic bags. Storing the plastic bag for about a year without breaking it will not affect its lifespan and performance. After the plastic bag is opened, it should be used as soon as possible to avoid adverse effects on the components caused by NaHSO3 oxidation in the air. Therefore, the film should be opened as much as possible before use.
(1)After the equipment was tested, we used two methods to protect the film. Test run the equipment for two days (15-24h), and then maintain it with a 2% formaldehyde solution; After running for 2-6 hours, use a 1% NaHSO3 aqueous solution for maintenance (the air in the equipment pipeline should be drained to ensure that the equipment does not leak, and all inlet and outlet valves should be closed). Both methods can achieve satisfactory results. The first method is more expensive and can be used when idle for a long time, while the second method can be used when idle for a short period of time.
(2) Calcium scale: can be judged based on the quality of raw water and design parameters. For carbonate water, if the recovery rate is 75% and scale inhibitors are added during design, the LSI of the concentrated solution should be less than 1; When no scale inhibitor is added, the LSI of the concentrated solution should be less than zero, and generally no calcium scale will be produced.
(3) A 1/4 inch PVC plastic pipe can be inserted into the component to test the performance changes of different parts of the component for judgment.
(4) Determine the type of pollution based on changes in device performance.
(5) Acid washing (such as citric acid, dilute HCl) can be used to determine calcium deposits based on the cleaning effect and cleaning solution. Further confirmation can be obtained through analysis of the composition of the cleaning solution.
(6) Chemical analysis of cleaning solution: Take raw water, cleaning solution, and cleaning solution, and analyze three samples.
After determining the type of pollution, it can be cleaned according to the methods in Table 1 and then disinfected for use. When the type of pollution cannot be determined, the steps of cleaning (3)+disinfection+0.1% HCl (pH 3) are usually used for cleaning.
