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UDC 628.179.2

Aksenov V. I., Galkin Iurii

Zero waste VIZ-Stal’ LLC recycling system of industrial water supply

Summary

The history of developing the first in metallurgy zero waste recycling system of industrial water supply of a transformer steel cold rolling plant at the Verkh-Isetsk steelworks (Ekaterinburg) is described. Since building the plant was planned in the centre of the city with the population of 1.5 million people on the bank of the Verkh-Isetsk pond near the drin­king water intake it was required to design a system of industrial water supply with complete elimination of the wastewater and industrial wastes discharge into the environment. The first step of developing the system was retrofitting a vitriol unit for the removal of environmentally hazardous wastes – spent concentrated pickling plant liquor. Hereafter the flotation technology of oil emulsion wastewater treatment was developed. In the course of experimental studies the efficiency of using clarifiers with suspended sediment in the process of removing palm oil from recycled water of the cold rolling mill was investigated. Most attention was paid to the technical solutions of processing the wastes generated in the process of industrial wastewater treatment. The unit for oil waste incineration was designed. Wastewater sludge was initially dewatered in the filter-presses, and then dried. Designing an evaporation plant for thermal desalination of blowdown water of the closed-loop cycles of the transformer steel cold rolling plant and wastewater from the chemical treatment of the thermal power plant effluent provided for the zero discharge of the entire industrial water supply system. The experience of the Verkh-Isetsk steelworks, particularly in relation to processing solid wastes and wastewater desalination, was used in designing efficient water supply systems for various industries including the upgrade of the Novolipetsk steelworks water supply system.

Key words

wastewater , desalination , steel industry , spent pickling plant liquor , zero discharge water supply system , environment

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UDC 628.179.34

Lerner А. D., Inchagov А. D. , Sliusarenko A. V.

Ways to reduce unaccounted-for-water in public water supply systems

Summary

In the process of improving the efficiency of water and wastewater services the reduction of unaccounted-for-water is of crucial importance. New approaches to the evaluation of these amounts with the selection of physical losses of the utilities resource are suggested. The world experience of taking measures on reducing these amounts by concluding contracts with private operators guided by the actual results of achieving the projected reduction of the specific physical leakages and water losses is considered. The comparative financial evaluation of the measures on constructing water intakes and reducing unaccounted-for-water is presented. Economic, social and political factors inhibiting the process of actual reducing unaccounted-for-water are considered. The main reason of public utilities being reluctant to take measures on the reduction of water leakages lies in the lack of financial incentives and organizational projects. It is concluded that the owners of the water supply systems, as a rule local authorities, shall be involved in solving the problem. It is worth kee­ping in mind that reducing unaccounted-for-water (including the use of performance-based service contracting) shall not be considered as a new formula for eliminating numerous shortcomings in the operation of water utilities, because these shortcomings result from the more fundamental problems. Successful public water supply management without introdu­cing new capacities, in its turn, can predetermine the structural reforms required to ensure the efficient operation of water and wastewater services and private business in satisfying the growing water demand of population and industries.

Key words

water leaks , unaccounted-for water , utilities resource management , performance-based service contracting , water supply efficiency

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UDC 628.1.032

Vasil'eva A. I., Kantor L. I., Trukhanova N. V. , Melnitsky I. A.

Polycyclic aromatic hydrocarbons in the water sources of Ufa

Summary

The results of long-term monitoring of the polycyclic aromatic hydrocarbons concentrations in drinking water and water sources at the three water intakes of Ufa with the use of high performance liquid chromatography with fluorimetric detection are presented. The qualitative and quantitative composition of polycyclic aromatic hydrocarbons has been investigated. The identification of possible sources of polycyclic aromatic hydrocarbons inflow into the Ufa River was carried out with the help of the system analysis of the relative composition of polycyclic aromatic hydrocarbons by some typical ratios of molar concentrations of separate compounds. The prevalence of petrogenic sources of polycyclic aromatic hyd­rocarbons inflow was found out. Studying the seasonal dynamics of their concentration in the Ufa River water showed that the maximum concentrations were observed during autumn-winter period, and minimum concentrations in summer. Comparing the results of the studies with the published data on river pollution in Europe, America, and China showed that the level of polycyclic aromatic hydrocarbons in the Ufa River was basically low or close to the natural background. Monitoring of polycyclic aromatic hydrocarbons in the major water source of Ufa is a reasonable requirement since any deviation from the background pollution level or any changes in the qualitative composition of polycyclic aromatic hyd­rocarbons can be indicative of the increased man-induced impact on the water source and consequently of the risk of the drinking water quality deterioration.

Key words

potable water , polycyclic aromatic hydrocarbons , pyrogenic and petrogenic sources of hydrocarbons emission , molar concentration ratio

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UDC 628.165:66.081.63

Removing calcium carbonate from reverse osmosis concentrate
by crystallization with seeding agent

Summary

The technology of removing calcium carbonate from reverse osmosis concentrate in the process of crystallization with seeding agent is described. Seed crystals are suspended in recycling concentrate flow. Owing to calcium carbonate depositing on the seeding agent the total salt content of concentrate decreases and high filtrate flow rate is provided that facilitates concentrate disposal. To implement the technology membrane apparatus with «open channel» are used that are resistant to the impact of membrane transfer of slightly water-soluble salts and suspended matter. Seed crystal growing is provided by dosing into concentrated caustic soda solution. Grown seed crystals were partially removed by sedimentation after hydraulic membrane wash. With the help of experimental diagrams it is possible to determine calcium carbonate crystallization rate depending on the influent water composition, the number of the seeded crystals, and filtrate yield. Process flow diagram of a continuously operating reverse osmosis plant is suggested. The methods of the process design are described: selecting the amount of recycling seed crystals, determining caustic soda consumption and tank size for calcium carbonate sludge precipitation. The estimations showed that to provide for calcium carbonate crystallization du­ring continuous operation of the reverse osmosis plant caustic soda solution in amount of less than 5% of its stoichiometric amount required for the precipitation of the same amount of calcium carbonate from the influent water shall be regularly dosed into the recycling concentrate flow.

Key words

concentrate , water stabilization , concentrate utilization , reverse osmosis unit , calcium carbonate crystallization , seed crystals

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UDC 628.16.066.7

Volftrub L. I.

The experience of operating lamella settlers and clarifiers with built-in flocculation chambers

Summary

The results of upgrading primary water treatment facilities – flocculation chambers, sedimentation tanks and clarifiers based on the use of low-flow and low-pressure recirculators and lamella honeycomb modules made of polyethylene film 250–300 µm thick designed by ECOHOLDING Group experts are presented. The developed method of jointing film into a honeycomb construction with an inner rigid frame provides for the ruggedness and spacial stability of the honeycomb module and allows stretching it on the frames on perimeter only. Firm jointing of the film allows manufacturing a honeycomb construction of any size and angle of slope providing minimum loss of clarifying surface of the facilities of any configuration, both radial and rectangular. For long-term operated facilities honeycomb modules are tailormade after each of them has been measured. The possibility of ensuring the required recirculation rate at low head loss and minimum liquid flow rate to prevent the recycled suspension from destruction and facilitate efficient floc formation is an essential advantage of the developed methods of recirculator designing and constructing. The presented high-efficient methods of coagulation and sedimentation improvement form the basis of prefabricated «Struiia» and «Vlaga» modular water treatment units with 100–12000 m3/day capacities. The units are designed for natural water treatment: turbidity and color removal, softening, defluorination, de-ironing (composite forms, high concentrations of iron) and disinfection. They are used in water supply systems of settlements, towns, hospital care and health resorts, sport centers, fish farms, industrial enterprises or separate production facilities.

Key words

turbidity , water treatment , modernization , residual aluminium , flocculation chamber , lamella settler , clarifier , honeycomb module

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УДК

От обработки осадка до выработки энергии: комплексное решение компании ANDRITZ (Австрия)

Аннотация

Группа компаний Andritz AG – международный машиностроительный концерн (со штаб-квартирой в городе Грац, Австрия), которому уже более 150 лет, поставляет комплексные установки и отдельные машины для различных отраслей промышленности. Производство сепарационного (включая тепловое) оборудования для химических, металлургических, пищевых, коммунальных предприятий – одно из ведущих направлений деятельности отделения концерна – Andritz Separation.

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UDC 628.35:661.63

KOZLOV M. N., Kevbrina M. V., Nikolaev Yu. A., Dorofeev A. G., GRACHEV V. A., KAZAKOVA E. A., Aseyeva V. G., Zharkov A. V.

Single-reactor technology of nitrogen removal from wastewater

Summary

The experts of R&D Centre of «Mosvodokanal» OJSC developed high-effective technology of removing nitrogen from wastewater. The technology was tested at the Kur’ianovo wastewater treatment plant of the city of Moscow during processing filtrate of the digested sludge belt thickeners. The method is based on the use of specific Anammox-bacteria that oxidize ammonium with nitrite under anoxic conditions. Filtrate is processed in a sequencing batch reactor with complete mixing (SBR-reactor). Partial nitrification processes (ammonium oxidation into nitrite), ammonium oxidation with nitrite and organic matter oxidation are carried out in one reactor. Retention of extremely slow growing biomass of Anammox-bacteria has been a critical problem for all the reactors. In this particular case the problem was solved with bacteria adhesion on the reactor walls and the feed as well as with flotation. To evaluate the treatment efficiency standard methods were used. The developed single-reactor modification of the anoxic oxidation of ammonium differs from the well-known by the following parameters: high nitrogen removal efficiency, the method of biomass bacteria retention in the reactor, the availability of new Anammox bacteria, heterotrophic denitrification. All other conditions being equal the integration of Anammox single-reactor technology requires the size of the facilities ten times smaller than double-reactor technology; for this reason it is more preferable for implementation. The new technology was given the name AUTOHETAMMOX.

Key words

wastewater , nitrogen removal , bioreactor , nitrification-denitrification , anammox bacteria

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UDC 628.356

Dorofeev A. G., KOZLOV M. N., Aseyeva V. G., Kevbrina M. V.

Causes and methods of control of foam formation in aeration tanks

Summary

The phenomenon of foam formation caused by the development of filamentous microorganisms is a common problem observed at the wastewater treatment facilities. Foam types, microorganisms responsible for activated sludge bulking and foaming are described. The causes stimulating mass growth of filamentous microorganisms in aeration tanks: high concentration of grease and oil products in wastewater, high sludge age and low concentration of dissolved oxygen in aerobic zones of aeration tanks have been analyzed. The experts of R&D Centre of «Mosvodokanal» OJSC developed the criteria of evaluating the number of filamentous nocardioformic actinomycetes in the process of microscopic investigation of the sample. The simple and practical method of quantitative determination of activated sludge filamentous microorganisms developed and used in «Mosvodokanal» OJSC is presented. Special attention is paid to the methods used in the world practice for prevention and elimination of foaming in aeration tanks: improvement of primary settling tanks operation, sludge age control, optimization of dissolved oxygen concentration, chlorination, the use of extractors, surface foam traps, anti-foaming agents, coagulants and polymers. The analysis of world practice gives evidences that methods of foam control shall be selected with account of the specific features of the technology used and parameters of incoming wastewater. Comprehensive measures including both short-term and long-term methods of foam control turn to be most efficient. In connection with global prevalence of foaming phenomenon at the biological municipal wastewater treatment facilities it seems appropriate to take into account the technical and technological means of foam elimination already at the stage of designing treatment facilities.

Key words

wastewater , biological treatment , foaming , filamentous bacteria , activated sludge bulking , anti-foaming agent

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UDC 628.35:661.5

Kevbrina M. V., Gavrilin A. M., Kozlov I. M.

The new form of pre-fermentation process arrangement for removing nutrients from wastewater

Summary

The concentration of readily available organic matter determines the process stability of biological phosphorus removal from wastewater. The low value of this parameter is typical for municipal wastewater in Moscow. Raw wastewater sludge pre-fermentation (acidofication) is one of the methods of increasing the readily available organic matter fraction. A new arrangement of pre-fermentation process has been implemented in the industrial-scale aeration tanks of the Moscow wastewater treatment facilities operating after the process flow scheme of the University of Cape Town (UCT). Compared to the traditional pre-fermentation process flow scheme taking place in a primary settling tank or reactor prefermenter the process is arranged in the first anaerobic zone of the aeration tank. Here, in the absence of mixed liquor mixing, a thickened layer of activated sludge is formed accompanied by pre-fermentation of organic matter sorbed onto sludge. Meanwhile the anaerobic zone carries on its main function in the treatment process related to biological phosphorus release by means of phosphate accumulating bacteria consuming volatile fatty acids. Increasing the concentration of volatile fatty acids in mixed liquor in anaerobic zone by means of pre-fermentation stabilizes phosphate removal from processed wastewater. Arranging pre-fermentation process in the first corridor of the aeration tank is more advanced and cost-effective compared to the traditional process arrangement in settlers-prefermenters owing to saving expenditures on mixing and eliminating construction or upgrade of additional tanks (prefermenters, settling tanks).

Key words

wastewater , acidification , readily available organic matter , prefermentation , raw sludge , biological dephosphatation