Introduction: As everyone knows, in the recycling of wastewater, the wastewater contains oxidants, such as potassium permanganate solution, hexavalent chromium, or oxidized pesticide fungicides, such as sodium hypochlorite solution, in the pretreatment process. Control the environmental pollution of microbial strains. If this oxidizing chemical substance is not resolved and enters reverse osmosis system, the aromatic polyamide separation layer on the surface of reverse osmosis membrane cartridge will be separated, resulting in a significant reduction in membrane characteristics that cannot be repaired, specifically as salt removal rate Reduce and increase the water production rate. Generally, the front membrane elements are more susceptible to damage than other parts. Oxidation under the neutral or alkaline pH standard will damage the membrane more. reverse osmosis element membrane damaged by oxidation cannot be detected by mechanical equipment such as vacuum pump test. Such acid damage can be evaluated based on the staining agent of reverse osmosis element membrane or the small membrane specimens.

1. Determination method of oxidation of reverse osmosis element membrane

The anatomy of reverse osmosis element membrane and the analysis of the pulsation damper can be used to determine oxidative damage. Once the membrane element is oxidized and damaged, only replace all the damaged elements without other preventive measures.

2. Preventing the oxidation of reverse osmosis element membrane

(1)Ensure that there is no oxidizing chemical substance in the reverse seepage water:
①. Classify wastewater resources, and restore and treat the wastewater containing oxidants before entering the reverse osmosis membrane 3;
②. Install an online ORP instrument panel or residual chlorine detection instrument on the reverse osmosis water inlet. According to the addition of oxidants such as sodium hydroxide, check immediately to ensure that there are no oxidizing chemicals in the water. It is recommended that the ORP value should not exceed 300mV, and the permanganate index component should be less than 0.1ppm. If it exceeds the above data information, an oxidizer should be added or the amount of oxidant should be increased, and the operation of the system should be terminated if necessary.
(2) The reverse osmosis cleaning system should be separated from the ultrafiltration membrane cleaning system to prevent the permanganate index of the ultrafiltration system from leaking into the reverse osmosis system software.

(3) Use non-oxidizing bactericides such as isothialine or DBNPA.