The use of ozone in surface water purification for public water supply of small communities

Summary

Two options of using ozone in purification of water from surface water supply sources with excess concentrations of organics in block-modular plants of small capacity are considered. Ozone effecting the changes in the basic water quality parameters is shown. The use of ozone in surface water purification extends the potential of the technologic process control under frequent seasonal fluctuations of the raw water quality, improves the quality of water after purification which is most important in the operation of small capacity plants. Besides, ozonation provides for reducing significantly the dosages of chemicals (coagulant and flocculant), and in some cases (during certain seasons) eliminating completely their use. The process studies carried out in a block-modular plant manufactured by «Moskosvskie Ozonatory» Company showed that the ozonation of the Volga River water for public water supply can be carried out using two process schemes: ozonation and sorption in carbon filters; or coagulation, ozonation and sorption. The parameters and conditions of using the ozonation, coagulation and sorption methods were specified; their efficiency at the minimum required chemical dosages was determined. It was stated that the use of ozone in block-modular plants for surface water purification provided for improving significantly the quality of drinking water regardless of the seasonal fluctuations in raw water quality; improving the integrity of the water supply system by all the parameters including microbiological ones. The effect of certain structural and technological solutions at the facilities on the water purification efficiency was noted.

Key words

potable water , ozonization , surface water source , coagulation , organic pollutants , block-modular plant

Shortcomings and omissions in low-capacity wastewater treatment complexes being under design, construction or operation (for discussion)

Summary

In recent years, massive use of packaged plants designed for wastewater treatment in small settlements and food industry enterprises has been noted. Today, the market is saturated with offers from both domestic and foreign companies involved with designing, assembling and commissioning packaged plants based on advanced technologies for wastewater treatment that provide for reducing biochemical oxygen demand (BOD), suspended solids, nitrogen and phosphorus to maximum permissible concentrations. Thorough analysis of the designs of many packaged plants and recalculation checks, full-time training of operating personnel of the packaged units under operation, as well as on-site and remote participation in commissioning these facilities gave the authors of this article the opportunity to identify the reasons that mitigate the achievement of the required degree of wastewater treatment. The main reasons for the unsatisfactory performance of newly commissioned packaged plants are design faults, omissions and poor operation. Of the many reasons, only frequently occurring, poorly chosen engineering solutions are considered. Each unsuccessful technical solution is accompanied by detailed comments proving the negative effect on both the technological process and effluent quality. The use or even simple knowledge of the results of the work presented for discussion will prevent designers and manufacturers from the future replication of design shortcomings and omissions in newly constructed facilities, and will allow them to determine possible options for upgrading already operating packaged units to bring them to the normal process
mode.

Key words

wastewater treatment , designing , construction , sewerage treatment facilities , block-modular plant , commissioning , design shortcomings and omissions

Efficient treatment of surface runoff

Summary

The experience of practical operation of flow-through systems for surface runoff treatment in different real-life environment on the territory of the Russian Federation showed their complete technological failure. In the estimation of specialists, the process and design parameters of flow-through plants do not comply with the design standards in force in the Russian Federation, the declared degree of surface runoff treatment being unachievable; that is, virtually, flow-through systems simulate treatment processes. Along with the traditional set of pollutants typical for surface runoff (sand, suspended solids, oil products and heavy metals), microplastics pose a real threat to water bodies that receive storm water. Technological inconsistency of flow-through treatment systems and new objective tasks of removing additional types of pollution from surface runoff necessitate the use of reliable process solutions for the treatment of surface runoff.

Key words

surface runoff , local treatment facilities , block-modular plant , pilot tests , flow-through systems , accumulating systems , microplastic

The use of ozone in surface water purification for public water supply of small communities

Summary

Shortcomings and omissions in low-capacity wastewater treatment complexes being under design, construction or operation (for discussion)

Summary

Efficient treatment of surface runoff

Summary

Journal VST