The technology of water purification from the source in conditions of high anthropogenous impact (substantiation, design, introduction)

Summary

The concept of «efficient water purification» is suggested, the selection criteria are set out. Process flow diagram of water abstraction and purification facilities has been designed including: primary water purification with removal of suspended solids and phytoplankton in prefilters with floating media; chemical water treatment in the process of clarification in lamella plate clarifiers and filtration in two-stage filters with inert and heavy media with regular addition of fine-granulated sorbent between the stages; combined water disinfection with the use of weak sodium hypochlorite solution and uv-radiation. The results of pre-design testing the technology of the Don River (the Bol’shaia Kalancha river arm in conditions of high anthropogenous impact) water purification at the test bench are presented. Chemical free water filtration in prefilter media provides for reducing phytoplankton loading approximately by 26–38% and suspended solids loading by 10–35% at the basic facilities at less than 50 m/h filtration rate. Uniform and efficient mixing and floc formation are provided within 0.5–1.5 and 10–15 minutes, relatively, at the speed of the mixer blade rotation of 185 and 60 rpm and recommended coagulant dosage of 2.5 mg/l (10 mg/l in case of sharp deterioration of the water quality). The operation of a nanofiltration plant during the period of water quality deterioration ensured reducing hardness, total dissolved solids, sulfate and chloride concentrations. The basic process parameters of separate units of the process flow scheme that provide for reliable compliance with the standard water purification degree are defined. Based on the study results the recommendations on designing were developed and the water abstraction and purification facilities with a capacity of 150,000 m3/day were designed. At present the facilities are under construction.

Key words

reagent treatment , suspended substances , phytoplankton , natural water , filtration , anthropogenous impact , efficient water purification technology , water abstraction and purification facilities , pre-design testing