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ABSTRACT
Low drinking water quality standards may be explained by inefficient water treatment technology, the use of outdated chemicals as disinfectants and secondary water pollution during its transportation to the ultimate consumer via the poor quality water supply systems. The paper describes chlorine dioxide disinfection technology with the help of DCh-100 at drinking water treatment plant with capacity of 45600 m3/day. DCh-100 type automated unit is made in Russia. The DCh-100 local automated plant producing a highly efficient and economical "Chlorine Dioxide and Chlorine" Compound Disinfectant from readily-available raw materials (sodium chlorate, sodium chloride, and sulfuric acid) for drinking water treatment and disinfection. The optimal chlorine dioxide dosing was identified: 1) During primary chlorination at the stage of pretreatment oxidation (chlorine was used for secondary disinfection). The dose of chlorine dioxide was 0.43-0.85 mg/l at the research season. 2) During two-stage scheme of water disinfection. Chlorine dioxide was used for pretreatment oxidation and secondary disinfection. The dose of chlorine dioxide was 0.30-0.40 mg/l for pretreatment oxidation and 0.15-0.20 mg/l for secondary disinfection process. 3) During one-stage disinfection. The dose of chlorine dioxide 0.26-0.33 mg/l was chosen. For the given disinfecting modes the optimal dosing of coagulants and flocculants was identified1.
Keywords: drinking water, disinfection, chlorine dioxide, water treatment plant, optimal dose.
INTRODUCTION
Disinfection is the process by which disease-causing pathogens are destroyed. Disinfection also provides additional protection for any contamination that may occur in the distribution system. The commonly used chemical disinfectant in Russia is chlorine gas. But now chlorine dioxide is increasingly used for disinfection in small drinking water treatment plants.
Chlorine dioxide is an extremely effective disinfectant, which rapidly kills bacteria, viruses, and Giardia, and is also effective against [1].Cryptosporidium. Odor [2] and disinfection byproducts such as trihalomethanes [3, 4] could be efficiently controlled by chlorine dioxide disinfection. ClO2 also destroys sulfides, cyanides, and phenols [5], controls algae [6], and neutralizes iron and manganese ions [7].
This article defines the optimum working dose of the chlorine dioxide and the coagulant on water treatment plant (WTP) of the city of Zlatoust (Russia, Chelyabinsk region) in winter.
1. METHODS
1.1. ZLATOUST DRINKING WATER TREATMENT PLANT
The city of Zlatoust is located in Chelyabinsk Region (Russian Federation). Its population is about 170 000...