Formation Of Inorganic By-products Of Chlorine Dioxide In Drinking Water And Its Control Method

As the fourth generation of drinking water disinfectant, chlorine dioxide has theadvantages of high efficiency, broad spectrum and has no organochlorines generatedwhen reacts with organics in water. In recent years, many water plants started usingchlorine dioxide as water treatment agent, and results prove that the ideal. However, theproblem of inorganic byproducts which easily exceed has never been effectivelyresolved, seriously hindered the development of chlorine dioxide.On the basis of related literatures and field investigation, the research train ofthought of this paper comes from the three main sources of chlorine dioxide inorganicbyproducts, the process of chlorine dioxide decomposition, producing and reaction withwater.Study the law of inorganic byproducts produced in the process of its decomposition,analyses the influence of the temperature, light intensity, pH and initial concentration ofchlorine dioxide on attenuation rate and the rules of byproducts generated, the resultsshow that the discharge of inorganic byproduct less affected by decomposition. Thefactors which influencing the rate of decomposition, light intensity> temperature>pH> initial concentration, avoiding light is the most effective measures to slow theprogress of the chlorine dioxide decomposition itself.Study the rule of inorganic byproduct produces by chlorine dioxide generatorwhich of different principle, analyze the influence of generator operation conditions onthe conversion, purity of ClO2and the production of chlorate, the results show that theR11generator itself do not produce chlorate and chlorite; Run under the volume rate ofhydrochloric acid and sodium chlorate is1:1.2and the temperature of65℃, thechlorate produced by R5generator can be reduced to a certain degree; R5generatorincrease mother liquor circulation, the production of chlorate reduce by25%; Increasedthe gas-liquid separation device can fundamentally solve the disadvantages of thegenerator producing chlorate.Study the law of inorganic byproduct produced in the process of pretreatment. Theresults showed that the existence of the chlorine will promote chlorite into chlorate, andthe discharge of chlorate can be reduced by increase the purity of chlorine dioxide. Theproduction of chlorine dioxide by-products depends on chlorine dioxide dosing quantity,less affected by other factors. When the dosage of ClO2between0~1.0mg/L, thequantity of chlorite is0.7times of the dosing quantity of ClO2, when the ClO2dosingquantity is1.0~3.0mg/L, the quantity of chlorite is0.5times of the dosing quantity ofClO2, when the ClO2dosing quantity is3mg/L~5.0mg/L, the quantity of chlorite is0.4 times of the dosing quantity of ClO2.The time intervals between adding ClO2andcoagulant should be controlled in10min, and the dosage should be approximate threetimes of manganese content when used to remove manganese in raw water. The dosingposition of chlorine dioxide should after the coagulant, and the dosage should be under1mg/L when ClO2is used for removing algae.