Water treatment activated carbon for the removal of chroma and turbidity: turbidity is caused by suspended substances such as mud sand, clay, organic matter, inorganic matter, plankton, etc. Caused by particulate matter. The turbidity and color in the water are mainly removed by the conventional treatment process of “coagulation-sedimentation-filtration-disinfection”. Although the water treatment activated carbon-ozone system is not as effective in removing turbidity and color in water as the conventional treatment process, it also plays a certain role in removing it.
The removal of turbidity by activated carbon system for water treatment mainly relies on the interception effect of the carbon column. However, the influent turbidity of the carbon column should not be too large, otherwise it will increase the recoil frequency of the carbon column, accelerate the wear of the activated carbon, shorten the service life of the activated carbon, and increase the cost of water treatment. In addition, when organic matter is present in the water, it is easy to adsorb on the surface of the particles and cause steric hindrance to stabilize. Ozone can oxidize and decompose these organic matters, thereby inducing destabilization of the particles. The use of pre-ozonation can generally improve the removal efficiency of particles and turbidity in the coagulation filtration process, while at the same time it often reduces the removal of organic matter in the coagulation process. The coagulation unit removes large molecules of organic matter, and ozonation will produce small molecules with low molecular weight and strong polarity, which will affect the effect of coagulation. However, the small-molecule organics after ozonation usually have better biodegradability than the large-molecule organics before ozonation. In addition, small molecules are more easily absorbed by organisms. Therefore, the removal of organics is completed by the biological activated carbon unit.
Ozone has outstanding decolorizing ability. The color of natural water comes from the decomposition products of humic acid. Usually, the unsaturated part in the decomposition products is the cause of the color development of these substances, which is called chromophore. Ozone can break the C=C double bond to generate ketones, aldehydes or carboxylic acids. Once this conjugated part is destroyed by oxidation, the color will follow, but this does not mean that the organic matter that causes the chromaticity can be completely oxidized to CO2 and H2O, but the chromophore is destroyed. The biological activated carbon ozone system has a good chromaticity removal effect, which is mainly due to ozonation, adsorption on the surface of activated carbon and biodegradation. It should be pointed out that the total effect of chromaticity removal also includes changes in the absorbability and biodegradability of organics in the water after ozonation. In addition, part of the removal of chromaticity by the biological activated carbon-ozone system is to directly pass through the carbon column to intercept the color-causing particulate matter and suspended colloids.