Bromate Control In Ozone-Activated Carbon Process

The eastern section of the South-to-North Water Transfer Project are of great significance to ensure people’s stable life and the production of agriculture and industry in Shandong Province.Now,with the deterioration of water quality conditions and the increasing demand for water quality,ozone oxidation process is applied to water treatment plant frequently,the subsequent bromate disinfection by-product problem is also increasingly serious.In order to investigate the effect of ozone oxidation on the bromate generation risk in the actual operation of the waterworks in the eastern part of the South-to-North Water Transfer Project,the effect of the raw water quality on the bromate production,potassium permanganateControl of Bromate Formation by Divided Dosing Process and Removal of Bromate by Activated Carbon.This paper examines the following:1.The water samples of the Nansi Lake were mixed with the water samples of Dongping Lake,the water samples of Xicheng Reservoir,the water samples of Shuangwangcheng Reservoir and the water samples of the Yangtze River,and the water quality of the mixed water samples was improved by coagulation.Ozone oxidation treatment.The dosage of coagulant is 24 mg/L(the active ingredient of Al2O3 is more than 10 %,the dosage of ozone is 0-10 mg / L,and the volume of experimental water is 2 L.The results showed that the dosage of ozone was 10-10μg/ L,and the dosage of ozone was between 8-10 mg/L.When the amount of ozone is the same,the amount of bromate produced after coagulation is higher than that of uncoagulant.Mixed water samples after ozone treatment,DOC,ammonia and other components have a certain degree of increase,UV₂₅₄,turbidity with the increase in ozone dosage decreased.2.Ozone oxidation experiment was carried out on the basis of the water samples of the Nansi Lake or Dongying Reservoir or the water samples of Qingdao Sikongtan Reservoir and the raw water along the reservoirs along the Shandong section of the South-to-North Water Diversion Project.The bromine ion concentration,ammonia concentration,organic concentration,p H,peroxidation Hydrogen concentration and ozone oxidation of the pre-oxidation process and ozone dosing method.It can be seen:（1）Due to the role of organic matter,raw water ozone concentration decay rate was significantly higher than the pure water decay rate;（2）Ozone dosage is not changed,the higher the bromide ion concentration in the water sample,the greater the bromate production.When the bromide ion concentration increased from 250μg/L to 450μg/L,the amount of bromate was increased by 40%.（3）Ozone process has a high removal rate of UV₂₅₄,the removal of DOC is poor,preozonized water SUVA value decreased.The lower the SUVA value of the water sample,the more bromate production,when the ozone dosage is 5mg / L,SUVA value decreased by 10%,bromate production increased by 61%.（4）Ozone dosage is constant,the higher the p H,the greater the amount of bromate generation.Ozone dosage is 5mg/L,when the p H dropped from 8.5 to 7.5,the bromate production decreased by 32%.（5）Hydrogen peroxide can effectively inhibit the formation of bromate.When the ozone dosage is 5.0 mg/L,the amount of hydrobromide produced by adding hydrogen peroxide is reduced by about 20% to 100%.（6）Pre-oxidation of potassium permanganate can inhibit the formation of bromate in the ozone process,and ammonia can improve the pre-oxidation of potassium permanganate.When the potassium permanganate/ammonia concentration is 1mg/L,the bromate inhibition rate is close to 68% compared with the water sample without preoxidation.Potassium permanganate concentration of 1mg/L,when the ammonia concentration from 0.6mg/L to 1mg/L,the bromate inhibition rate increased by 54%.（7）The use of multi-point plus ozone can effectively inhibit the formation of bromate.When the dosage of ozone is 8mg/L,the inhibition rate of bromide is about 76%,and the inhibition rate of bromide at the three points is more than 95%.And the greater the total amount of ozone,the greater the inhibition rate of the addition of bromide to the bromate formation.3.The continuous adsorption of activated carbon on bromate was investigated using activated carbon column.At the same time,the effects of ultrasonic and microwave on the adsorption of bromate on activated carbon were explored.The analysis shows that:（1）The residence time of the activated carbon column and the concentration of the influent bromate were positively correlated with the removal rate.Under the continuous operation condition,the activated carbon could effectively remove the bromate salt,but the effect of removal was decreased obviously after a certain period of time.After continuous operation of activated carbon column 8 days after the bromate removal rate straight down to zero.（2）Activated carbon adsorption bromate,the coexistence of nitrate ions and bromate there is a competitive relationship.When the bromate concentration is 200μg/L and the nitrate concentration is 20-60mg/ L,the removal rate of bromate by activated carbon is about 30%.（3）Saturated activated carbon by regeneration,can effectively restore its ability to adsorb bromate.Microwave regeneration of carbon to remove bromate effect can reach 80% of new carbon.Ultrasonic regeneration of carbon can only reach about 10% of new carbon.