In the water quality pretreatment system, activated carbon filters can adsorb residual chlorine that cannot be removed in the previous stage of filtration to prevent the subsequent reverse osmosis membrane from being oxidized and degraded. At the same time, they can also adsorb small molecule organic matter and other pollutants leaked from the previous stage, which has a significant adsorption and removal effect on odors, colloids, pigments, heavy metal ions, etc. in water, and also has the effect of reducing COD. It is possible to further reduce the SDI value of RO inlet water to ensure SDI<5, TOC<2.Oppm。

Activated carbon filters mainly use activated carbon organic flocculants with high carbon content, high molecular weight, and large specific surface area to physically adsorb impurities in water to meet water quality requirements. When water flows through the pores of activated carbon, various suspended particles, organic matter, etc. are adsorbed in the pores of activated carbon under van der Waals forces; At the same time, chlorine (hypochlorous acid) adsorbed on the surface of activated carbon undergoes a chemical reaction on the carbon surface and is reduced to chloride ions, effectively removing chlorine and ensuring that the residual chlorine content in the effluent is less than 0.1ppm, meeting the operating conditions of the RO membrane. As time goes by, the trapped substances in the pores and between particles of activated carbon gradually increase, causing the pressure difference between the front and back of the filter to rise until it fails. Under normal circumstances, based on the pressure difference before and after the filter, reverse water flow is used to backwash the filter material, so that most of the trapped substances adsorbed in the pores of activated carbon are stripped off and carried away by the water flow, restoring the adsorption function; When the saturated adsorption capacity of activated carbon is completely exhausted, it should be regenerated or replaced to meet engineering requirements.