Experience of retrofitting the technology of wash water utilization at the Omsk water treatment facilities

Summary

The main phases of addressing holistically the problem water source pollution with wastewater generated at the Omsk water treatment plant are considered. The results of technologic pre-engineering that provided for determining the optimal flow scheme of the treatment process and filter wash water reuse as well for defining the process parameters of combined treatment of river and wash water are presented. It is shown that the chemicals mainly used for drinking water purification can be used for filter wash water treatment. The studies were carried out by test coagulation method, i. e. by adding various amounts of polluted wash water and chemicals used at the water treatment plant into raw river water. The efficiency of combined treatment of river water is improving with increasing the amount of added polluted wash water. The design concepts and process flow scheme of water treatment that provided for constructing and commissioning filter wash water reuse unit with minimum capital expenditures are presented. The operating experience affirmed the correctness of the adopted process and design solutions. As a result the abstraction of raw river water was reduced by 9–13% and wash water discharge into the Irtysh River- the water source was completely abandoned. Wash water treatment is carried out together with raw river water at the water treatment facilities. Herewith the drinking water quality fully meets the requirements of Sanitary Regulations and Norms 2.1.4.1074-01.

Key words

water treatment , reagent treatment , wash water , water reuse , resource conservation

Developing a unit for water pretreatment for the hybrid chemical-membrane purification system

Summary

At the present day developing and upgrading the methods for water pretreatment in membrane purification plants is a relevant objective. The purpose of this work has been the development and study of a small-sized water pretreatment unit based on the chemical method for the purification of heavily polluted water with high efficiency in terms of the degree of purification, chemical and energy consumption. A water pretreatment unit based on a dosing and mixing device for chemicals including jet hydrodynamic mixers – ejectors, has been developed. The device allows dosing chemical solutions in a wide range of injection coefficients and provides for improving the removal of hardness salts and heavy metals by more than 20%, and of oil products – by 8% compared to standard mixing with a blade mixer (120 rpm) owing to the mass transfer proceeding in an intense hydrodynamic field at Re >> Recr. Hybrid alumosilicic chemical was developed and studied that provided for reducing the concentration of toxic residual aluminum in purified water by an order of magnitude more (up to 0.02–0.05 mg/l) in comparison with other aluminum-containing reagents owing to the formation of mesoporous alumosilicic structures possessing the effect of volumetric sorption in 6–8 pH range. An experimental model of a portable water treatment plant with a unit of chemical pretreatment and membrane post-treatment based on the microfiltration technology using a porous titanium carbide membrane and low-pressure reverse osmosis technology with the use of a membrane made of a thin-film polyamide composite has been designed. It is shown that using a pretreatment unit provides for increasing the performance of the microfiltration device up to 3.7 times while removing oil products and hardness salts from water, and up to 4.3 times while removing heavy metals (copper). It is also shown that the developed version of the portable plant provides for a preset degree removing the main pollutants from heavily polluted wastewater in at the lowest specific energy consumption of 2.57 kWh/m³ compared to the analogues.

Key words

mobile plant , reagent treatment , microfiltration , water treatment , hybrid system , pretreatment , membrane methods , low-pressure reverse osmosis

Improvement of Treatment Technique of High Colour and Low Turbidity Water

Summary

Humic substances are governing natural pollutants of high color and middle color river water. NII VODGEO has conducted the studies of effects of non-organic and organic coagulants in combination with high molecular flocculants. In the course of studies the efficiency of water treatment with aluminium oxychloride and Polysept has been compared. To improve efficiency of treatment flocculants Praestol have been used. Molecular-mass distribution of humic acids in influent water and water treated with reagents has been investigated. Results of the experiments with natural water have been confirmed with the use of model solutions prepared on the basis of sodium humate and also humic substances extracted from soil, turf and river water.

Key words

coagulant , flocculant , reagent treatment , high color water , humic acids , fulvic acids , molecular-mass distribution , aluminum oxychloride , organic coagulant Polysept