Ozone has a good effect on COD removal, but its utilization efficiency is not high in practical industrial application. The main reason is that there are some other pollutants that will consume a lot of ozone, such as chroma and suspended solids, which greatly prolongs the amount and time of ozone.
Meanwhile, the dosage and removal effect of ozone will also be affected by the contact mode. The influencing factors of ozone oxidation mainly include the following aspects:
Dosage of ozone and water-soluble ozone
The dosage of ozone directly affects the removal effect of ozone on COD. Generally, the ratio of ozone dosage to COD removal in water is 2 ~ 4:1 in industry.
The actual dissolved amount of ozone in water will also affect the COD removal rate. Generally, there is an ozone oxidation threshold. When the concentration of dissolved ozone in water is lower than a specific value, ozone almost does not significantly remove COD. The threshold varies according to different water quality conditions.
Water quality impact
Water quality impact mainly refers to that other pollutants, such as chroma, NO2-N, suspended solids, etc., will affect the application and removal effect of ozone. Among them, there are many investigations on SS in water in engineering. Generally, it will enter the ozone section after pretreatment and filtration.
PH has a great influence on ozonation degradation. The pH of the system will directly affect the production of various free radicals dominated by hydroxyl radicals.
The contact mode between ozone and sewage will also have different effects on the oxidation effect. At present, the contact modes mainly include gas aeration disc aeration and jet device gas-liquid mixing. The general engineering experience is that the jet device for ozone has the highest gas-liquid mixing efficiency, but the operation cost will also increase.