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UDC 504.75.06:628.31

Pupyrev E. I., Shelomkov A. S.

Economic assessment of environmentally safe wastewater treatment technologies

Summary

In the competitive environment in Russia customers and investors shall take into account economic factors when designing municipal wastewater treatment facilities. Cost-effective and environmentally efficient wastewater treatment technologies are determined with account of regional specific features when siting the treatment facilities. Three representative groups of settlements are specified: rural (less than 20 thousand residents), towns (50-100 thousand residents), cities and megacities. The characteristics of municipal wastewater typical for every group are presented. Wastewater of rural settlements contains high concentrations of suspended solids and nutrients. Effluents of towns and cities contain heavy metals resulting as a rule from raw industrial wastewater discharges. The requirements to the effluent quality of typical settlements are presented. For every group of settlements the environmentally acceptable treatment technologies are suggested and economically substantiated. The following wastewater treatment technologies have been analyzed: full aerobic biological treatment; advanced biological treatment with nutrients removal (nitrogen, phosphorus); advanced biological treatment with nutrients removal (nitrogen, phosphorus) with tertiary treatment at filtration facilities and sorption filters. The suggested approach to the selection of a wastewater treatment technology with account of the economic and environmental conditions can be used in designing other systems of ecological purpose.

Key words

biological treatment , best available techniques , ecological safety , biogenic elements , municipal wastewater , economic assessment

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UDC 628.5.504.06

Zacharias Berndt

Hamburg – St. Petersburg: cooperation in water sector

Summary

The information on the cooperation between municipal water utilities – Hamburg Wasser and State Unitary Enterprise «Vodokanal of St. Petersburg» is presented. St. Petersburg is an economic, research and cultural centre, major transport hub and big sea port of the North-Western region of Russia. The city produces a substantial impact on the environment and water quality of the Baltic Sea. Hamburg is the second big German city and one of the biggest European ports. Hamburg and St. Petersburg since long have been bound by trading relations that provided for establishing the first German-Russian commonwealth of twinned cities. At present this background forms the framework for the cooperation of Hamburg Wasser and Vodokanal of St. Petersburg, the companies that provide for drinking water supply, wastewater disposal and wastewater sludge utilization. In this respect mutual exchange of experience in the field of operation upgrade and optimization, improvement of operation and power efficiency of the public water supply and wastewater networks and facilities as well as in the field of improving the existing regulatory framework is of high value. The requirements to the protection of the water bodies are extremely high for both companies, therefore both in Hamburg and St. Petersburg large-scale wastewater collection systems are under construction. All the Hamburg Wasser water and wastewater treatment facilities are fully independent of external power supply. At present in Vodokanal of St. Petersburg energy optimization of the pumping stations and upgrade of the wastewater treatment facilities operation are carried out.

Key words

losses of water , water supply , power saving , water disposal , specific water consumption

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UDC 628.316:66.081.63

Pervov A. G., Matveyev N. A.

The use of membranes for surface runoff and recycling car wash water treatment

Summary

The results of investigating the technology of surface runoff and recycling car wash water treatment with the use of reverse osmosis systems equipped with specially designed membrane units with «open» channel that provide for processing water with high concentration of suspended matter are presented. For processing raw wastewater in the membrane unit two concentrating stages are used: at the first stage – reverse osmosis membranes that ensure high quality treatment, and at the second stage – nanofiltration membranes that ensure concentrating solutions with high salt content with the minimum power consumption. The specific feature of the technology is in the utilization of the reverse osmosis concentrate that is removed from the system together with wet sludge. The results of the laboratory studies of storm water membrane treatment with the use of special roll elements with «open» channel and new BLF membranes are presented. It is stated that increasing permeate output to 0.9 results in 2.5–3-fold decrease of the equipment capacity. Car wash water undergoes the same treatment. The pilot tests show that increasing salt concentration in recycling water higher than 17 000 mg/l is impractical. The relationships of the increase of pollutant concentration in permeate and membrane capacity depending on the increase of the salt content in water under treatment and the ratio of volume concentrating in a reverse osmosis unit are presented. The parameters of membrane units operating with wastewater of this type with efficient removal of oil products, detergents and other pollutants are determined. Possible utilization of concentrate is shown.

Key words

suspended substances , filtrate , oil products , concentrate , reverse osmosis , surface runoff

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UDC 628.345.9.001.9

Linnikov O. D., Rodina I. V.

Comparative efficiency evaluation of a number of known flocculants

Summary

The results of comparative evaluation of coagulating activity of a number of known flocculants at full identity of all basic factors that affect the process of suspended and colloid-dispersed solids are presented. The investigations were carried out in laboratory conditions with model suspension of titanium dioxide in tap water with average solid phase particle size of 4.5 µm. The known flocculants were tested to compare their efficiency. The following series was received: Nalco 8103 ≤ Nanofloc ≤ VPK-402 ≤ Praestol 611 = Praestol 2510 ≤ Praestol 853 ≤ Praestol 655 ≤ Praestol 2500 ≤ Praestol 650. Comparing the flocculant efficiency with a fixed dosage of 5 mg/l resulted in another series: Nalco 8103 ≤ Nanofloc ≤ Praestol 611 ≤ VPK-402 ≤ Praestol 2510 ≤ Praestol 853 ≤ Praestol 655 ≤ Praestol 2500 ≤ Praestol 650. It was suggested to use 5 mg/l dosage of the following flocculants in the process of water clarification: Nalco 8103, VPK-402, Praestol 650, Praestol 655, Praestol 853, Praestol 2500, and 10 mg/l dosage of Nanofloc, Praestol 611, Praestol 2510. It was noted that the ion activity of the flocculants did not affect much their coagulating capacity. In the carried out tests the efficiency of all the tested flocculants was almost an order lower compared to that of aluminium- and iron-containing inorganic coagulants. The received results of the investigations can be used in removing suspended solids from natural and waste water.

Key words

clarification , coagulant , flocculant , sedimentation , suspension , coagulating capacity

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UDC 628.292.001.24

DAGILEV M. A.

Calculating the capacity of a receiving tank of a sewage pumping station

Summary

Methods of designing pumping stations according to the requirements of the updated version of SNiP 2.04.03-85 – «Set of rules 32.13330.2012. Code. Sewers. Public utilities» are presented. The basic requirements of the regulatory document and pumping unit manufacturers to the design of pumping stations are considered. It has been established that to provide for correct designing the minimum effective capacity of the pumping station receiving tank with several single-type pumps meeting the requirement to the number of pump starts is necessary: it should not exceed the maximum permissible number of starts for a definite time period. It is evident that the maximum number of starts occurs when all the normal pumps are in operation except one that is operating in turns. A formula of calculating the required effective capacity of a pumping station receiving tank with several single-type normal pumps has been derived. An optimal principle of pump operation at similar pumping stations is determined, pump operation modes, their start and shutdown levels are conside­red. An example of calculating the effective capacity of a pumping station receiving tank is set. Possible reducing the pumping station footprint is shown. The use of the suggested formulae for calculating the effective capacity of a pumping station receiving tank with guaranteed failure-free operation of the pumping units during the entire life cycle and retai­ning the manufacturer’s warranty is substantiated.

Key words

sewerage pumping station , capacity , pump , receiving tank , effective capacity , cycle time

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UDC 628.31:614.71

Kolycheva M. A.

Controlling malodorous emissions of wastewater treatment facilities

Summary

Wastewater treatment facilities feature malodorous emissions into the atmosphere that result from the process of wastewater treatment and contain mercaptans, hydrogen sulfide, ammonia, amines etc. The preventive measures against negative impact of malodorous emissions on the urban development include two stages: collection of the polluted emissions and their subsequent purification. Preventing emissions into the atmosphere and collecting gases are carried out by installing covers on the aeration facilities. The advanced and technically perfect method of air purification is used in «Iatagan» gas converters. The principle of «Iatagan» units operation is based on the combined effect of bulk barrier-streamer discharge and ozone on the molecules of hazardous and malodorous gases. The use of «Iatagan» gas converters is the best solution of the air purification problem at the wastewater treatment facilities.

Key words

air cleansing , sewerage treatment facilities , malodorous emissions , ozone , gas converter

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UDC 628.316.12:546.72

Filatova E. G., Pomazkina O. I., Dudarev V. I., Soboleva A. A.

Removing iron with carbon sorbent from plating wastes

Summary

The results of investigating adsorption capacity of sorbents in relation to iron ions (III) under static and dynamic conditions (with the use of isotherms and kinetic adsorption curves) are presented. To provide for removal of iron ions (III) and tertiary treatment of plating wastes IPI-T activated carbon was used that was produced from the wastes of phenol-formaldehyde resin production and modified with sulfosalicylic acid for IPI-Tm sorbent production was used. The maximum rate of sorbate passing through the sorbent layer was 5–7.5 ml/min which corresponded to the linear velocity of 1.5–2 m/h under full-scale conditions. The main factor that affects the sorption process is pH with optimal value of 1.79. Constants of BET adsorption equation for IPI-Tm modified sorbent were determined. The limiting sorption capacity of the monolayer was 128 mmol/kg, for IPI-T sorbent – 20.8 mmol/kg, limiting adsorption А∞ – 100 mmol/kg, adsorption equilibrium constant – 1·104; at that standard Gibbs energy of adsorption was 22.819 kJ/mol. Under dynamic conditions the time of the protective effect of IPI-Tm sorbent was 4 hours, i. e. 2 hours longer compared to IPI-T sorbent, and the volume capacity for IPI-Tm was 7.2 mg/l, i. e. twice as high as that for IPI-T.

Key words

wastewater , carbonic sorbent , adsorption , galvanic production , iron ions (III) , isotherm , kinetic curve

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UDC

KSB equipment safeguarding the health and environmental safety

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UDC 628.218

Chupin R. V.

Designing looped wastewater systems with bypass sewers

Summary

The aspects of simulating fluid movement in wastewater disposal systems of looped structure are considered. It is shown that separate bypass sewers can operate both with gravity and pressure flows. Meanwhile preliminary studying the flow hyd­raulic parameters is required. In the process of hydraulic network designing potential threat of wastewater underfloo­ding and surface spilling have to be analyzed first. It is suggested to determine wastewater flow rates that are distributed among separate bypass sewers on the basis of energy and mass-conservation equations (similar to Kirchhoff’s laws). General design procedure is proposed and examples of designing wastewater disposal systems with bypass network sections for the entire range of possible fluid movement modes including emergency situations are presented. The aspects of improving wastewater system integrity by introducing looped structures are considered. For the operators the design procedure can be helpful in centralized control systems in case of isolating accident failures or optimizing flow modes. In case of automatic flow distribution the design procedure provides for advance estimating control action on gate valves and simulating the aftereffect of their opening or closing. Looped structures can be used in the process of wastewater disposal system reconstruction and development; whereas the developed procedure of hydraulic designing will allow the design engineers to substantiate their parameters.

Key words

water disposal system , underflooding , bypass sewer , pressure and gravity flow