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Number 12 / 2014
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Literature lists to articles (doc)
Index of the Articles (doc, pdf), Published in the Water Supply and Sanitary Technique Magazine in 2014.
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UDC 628.14:62-523
Ageev M. K.
Current trends in water supply optimization
(review)
Summary
The main aspects of introducing SCADA-systems for automated control of water supply and wastewater disposal processes: synchronization of software with the installed control systems; erection of a programmable logic controller, introduction of algorithms of systemic optimization, synchronization of the telemetry system and control system at the facilities are considered. The basic technical factors (e. g. when a programmable logic controller and RTU blocks have been already connected to the centralized control system; the availability of separate algorithms at RTU-block level) that shall be taken into account when making a decision on the introduction and in the process of designing automated control systems as well as the principles of SCADA system operation by a special operating department are described. By the example of the companies that have introduced SCADA-systems for water and wastewater industry an analysis of the results in terms of absolute and relative indices is given. The capacity of some pumping stations operated by EBMUD Company was improved by more than 27%. During the first week of the system operation WSSC Company registered about 400 dollars per day cost cutting just at one of the pumping stations. For the second week this amount increased to 570 dollars per day and for the third week exceeded 1000 dollars per day. Similar effect was noted at other 17 pumping stations. Thus, SCADA-systems contribute to financial advantages by optimized and improved efficient control of water supply and wastewater disposal processes. The use of the relative international experience for the project implementation in Russia has been an effective solution.
Key words
automated control system , water and wastewater management , SCADA-system , plant management , automated accounting
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UDC 628.16:546.(72+711)
Askerniia A. A., Sorokina A. Iu., Dubinina G. A.
Microbiological aspects of natural underground water deironing and demanganation
Summary
The purpose of the presented work was studying the role of microorganisms that participated in the transformation of iron and manganese compounds in technogenic drinking water purification systems. The studies were carried out at the water treatment facilities of the Novourengoisk gas chemical complex and of Iuzhnyi settlement of Barnaul city. At different stages of water treatment process alongside with studying the composition of bacterial communities and number of different physiological and taxonomical groups of microorganisms performing bidirectional processes of Fe and Mn compounds oxidation and recovery the analysis of physical and chemical parameters of the studied water (concentrations of O2, CO2, CH4, NH3, soluble forms of Fe2+ and Mn2+, pH, temperature, oxidability) was carried out with an account of the observation seasonality. It is shown that during the operation of a single-stage water purification system the filters uploaded with inert filtering material are functioning as biofilters, and transformation of Fe and Mn compounds in technogenic water purification systems is provided by the microorganism activity. Precipitated forms of Fe and Mn sludge are represented by exclusively biogeneous (bacterial) structures of iron- and manganese-oxidizing bacteria. Depending on the physical and chemical conditions the latter are presented mostly either by Gallionella species (the Novourengoist water treatment facilities) or by filamentous ferrobacteria Crenothrix and Siderocapsa – Arthrobacter unicells. The efficiency of biological deironing and demanganation of underground water during single-stage purification process is determined by the physical, chemical and microbiological properties of the raw water and depends on the conditions required for microorganism evolution that are provided by the adequate choice of the process equipment and operation modes.
Key words
ground water , single-stage deironing and demanganation , autotrophic ferrobacteria , heterotrophic microorganisms
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UDC 628.171.001.24
Novitskaia O. S., Tkachuk A. A.
The impact of excessive water pressure on total domestic water consumption
Summary
The pattern of total domestic water consumption and water losses in residential buildings is presented. The main factors that influence the pattern formation are considered. It is taken into account that water consumption is formed not only as beneficial water use that reflects the actual water demand, but also as water losses including water wastage, nonproductive losses through valves and water leakages. It is shown that beneficial water consumption is associated with natural and physiological aspects; water wastage is determined by socio-economic conditions; nonproductive water losses are mostly formed under the impact of technical factors; whereas water leakages – under the impact of time factor. The relationships obtained during field tests between water flow rate and pressure are presented that take into account water consumption increase because of leakages and nonproductive use in residential sector. On the basis of the relationships the calculated nonproductive water rates and leakages in residential sector caused by excessive pressures at different water consumption patterns and diurnal average are cited as an example. It was stated that the highest nonproductive water use was observed at the maximum water consumption, the lowest nonproductive water use was observed at night (in percentage ratio); whereas in case with water losses – vice versa. The average daily water losses in a building calculated with account of water losses caused by excessive pressures at every floor were up to 40%. Considering the relationship between water flow rates in the distribution network and excessive pressures provides for approximating the estimated hydraulic pressure head in the distribution network to the actual values and improving the efficiency of the optimization measures.
Key words
water saving , excessive head , water leaks , beneficial water use , water wastage and nonproductive water use
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UDC 628.112.24
Ivashechkin V. V.
Durable wells with built-in downstream of the filter regeneration systems
Summary
The results of the studies of the durability of 224 unserviceable wells of 11 underground water intakes of Minsk city are presented. It is shown that the average service lifetime of the wells of typical design is 18–22 years, and the main causes of their outage are sanding and residual colmatage that cannot be removed by traditional repair works within the filters. A new design of a ground water well equipped with a system of downstream of the filter regeneration consisting of 4–5 polyethylene injection tubes (piezometers) is presented. The tubes have perforations opposite the well filter and are lead out onto the wellhead, installed in the hole clearance on the external boundary of the gravel package. Process flow schemes of chemical and chemical free well washing are suggested. It is shown that the symmetrical arrangement of the tubes provides for the radial directional washing flow in the gravel package at simultaneous operation of an airlift or a pump installed in the filter column. The technology of well construction is considered. The results of field testing the system of downstream of the filter regeneration of a new well in the mode of hydrodynamic washing drill mud and sludge out of the gravel package are presented. The suggested design of a water well with a gravel filter is specified by improved repairability, simplicity and can be recommended for underground water abstraction from soft water bearing rock.
Key words
water well , gravel filter , downstream of the filter regeneration , injection tube , near filter zone
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UDC 628.16.067.1
Filatov A. I.
Method of designing tubular porous rapid filter drainage
Summary
In recent years the specialists of water treatment plants pay much attention to rapid filter drainage systems of porous type. This design excludes the drawbacks typical for drainage systems with supporting gravel layers, major of them being gravel layer slip that causes frequent filter reloading (typically every 3–5 years). The method and basic formula for calculating tubular porous drainage are presented. In view of specific design tubular porous drainage calculations differ significantly from calculating widely used tubular perforated drainage systems of high resistance with supporting gravel layers. In the latter the pressure loss required for uniform filter wash occurs in one stage – in drainage openings. In tubular porous drainage design the pressure is successively lost in two stages – in the openings and outside porous layer, or in three stages – in the upper drain openings, inner porous layer, bottom drain openings. The summarized pressure loss in the mentioned two stages must provide for 95% uniformity of filter wash.
Key words
water supply plant , rapid filter , pressure losses , tubular porous drainage , wash uniformity
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УДК 628.356
Berezin S. E., Ovseichuk B. V., Ustiuzhanin A. V.
Air flow control in wastewater treatment
Summary
Energy consumption for the treatment and transportation of 1 m3 drinking water and wastewater in Russia is several times higher compared to the developed countries; whereas the capital investments are several times lower. This fact determines the advisability of investing into water and wastewater projects with the highest energy saving potential. This potential can be realized through the control of energy intensive units in line with diurnal and seasonal changes in water consumption and amount of wastewater removed. Up to 50% of electrical energy consumed by wastewater management is accounted for air blowers. Adjusting their operation can reduce energy consumption by 35%. Air flow control is an economically efficient measure both in the terms of energy consumption and return on investments in wastewater management. Three main methods of air supply for aeration are considered: throttling with a baffler at the suction nozzle of the air blower; adjusting the shaft speed with a variable-speed drive; adjusting the angle of the air flow attack before and after the impeller with the help of turning vanes installed inside the air blower. For comparison, e. g. in Germany, controlled air blowers are used at 390 wastewater treatment facilities in 145 cities. But in Russia from 297 cities with more than 50 thousand population they are used only at 15–20 wastewater treatment facilities. Instead, low efficient adjustment of sewage pumps in RF is used more often than in energy efficient countries. From global best practices the use of controlled air blowers instead of regular ones was paid off during 2–4 years at numerous facilities.
Key words
wastewater , aeration , pumping station , water supply-sewerage services , frequency-regulated electric drive , air blower
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UDC 628.35:661.5
Streltsov S. A., Nikolaev Yu. A., GRACHEV V. A., Aseyeva V. G., Mikhailova Iu. V.
Improving the efficiency of wastewater treatment by the method
of activated sludge enrichment with nitrifying bacteria
Summary
Ammonium concentration in effluent is one of the most important indicators of biological wastewater treatment efficiency. Ammonium oxidation to nitrates (nitrification) is executed by nitrifying bacteria characterized by low growth rate and high sensitivity to some adverse technologic factors (e.g. low oxygen concentration, toxicants). To provide for stabilizing the number of nitrifying bacteria, increasing their activity in bioreactors with activated sludge and improving the efficiency of removing nitrogen compounds from wastewater different processing technologies are used. One of them is bioaugmentation (inoculation of essential microorganisms or arrangement of conditions for their evolution with the purpose of improving the specific activity of biosystem, e.g. activated sludge). The specialists of R&D Centre of «Mosvodokanal» JSC studied the efficiency of nitrification process in an installation working after the process flow scheme developed in the University of Cape Town in combination with an additional bioaugmented reactor. In the reactor activated sludge is being enriched with nitrifying bacteria. At increased ammonium load simulated by adding liquid phase of digested sludge the main process line did not provide for reducing ammonium to the maximum permissible concentration of pollutants in fishery water bodies. The use of bioaugmented reactor allowed reducing ammonium concentration (N–NH4) from 40–50 to 0.4 mg/l. With that the resistance of nitrifying bacteria of activated sludge to toxicants (thiourea) showed no increase. However with the availability of a bioaugmented reactor the inhibiting effect was somewhat abated.
Key words
wastewater , biological treatment , nitrification , bioaugmentation , scheme of the University of Cape Town , bioaugmented reactor
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UDC 628.147.2
Karmazinov F. V., Melnik E. A., Ipatko M. N., Il'in Iu. A., IGNATCHIK V. S., Ignatchik S. Iu.
The method of evaluating the economic efficiency of water supply systems with pumping stations equipped with tanks
Summary
A method of evaluating the economic efficiency of the water supply systems with pumping stations equipped with tanks is presented that provides for optimizing at the design stage water conveying systems in remote areas. These systems are characterized by: low energy efficiency because of the pressure loss during water discharge and low network reliability during bypass operation caused by pressure fluctuation. The method takes into account the specific features of simultaneous operation of two subsystems: pipeline and valving subsystem and booster pumping subsystem. The selection of net discounted flow rate over the life cycle as a uniform optimization criterion for all the subsystems is substantiated. It is stated that the economic and energy efficiency of the investment projects of upgrading water conveying systems is a function of the actual inlet pressure in the supply pipelines and depends on the engineering measures aimed to improve it. These measures include the use of valves for downstream pressure control, mini-hydropower units and auxiliary low head pumping stations. By the example of Parnas booster pumping station in St. Petersburg it is shown that the use of the developed method allows improving the reliability coefficients of the water supply system to P(t) > 0.95 with simultaneous 17% reduction of the net discounted flow rate over the life cycle. In this case depending on the actual inlet water pressure in the supply pipeline the energy consumption of a pumping station is reduced by 22–60%.
Key words
pressure , water supply network , energy efficiency , pumping station , control valve
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UDC 628.334.1
Streltsov S. A., Kuriatnikov E. A.
High performance design of trash screens for wastewater treatment
Summary
The reliable operation of the treatment facilities of the municipal wastewater disposal system depends significantly on the efficiency and robustness of the trash screens installed in the head of the process flow at the treatment facilities. In addition trash screens not only protect the equipment from blockages but also prevent suspended solids from polluting natural water bodies receiving effluents. In order to improve the efficiency of trash capture the use of RS screen is recommended. It is highly resistant to mechanical damage caused by large-size impurities in wastewater which results in the reduction of the failure rate and the amount of repair works. The screen design includes a device for additional rake cleaning during the reverse movement to completely eliminate any risk of the rakes being wrapped with filamentary inclusions during the operation. An original mechanism of driving chain tensioning provides for eliminating rake jerking and skewing. The design ensures screen self-sealing in the process of installation into the channel to eliminate unscreened water breakthrough between the frame and channel walls. For the period of RS screens operation the following results were noted: full absence of filter cloth clogging; 3–4 fold screen output increase compared to the previously operated models; reduction of bottom sediments in the channel before the screens; high reliability in case of peak discharge of filamentary inclusions; reduction of energy consumption.
Key words
treatment facilities , wastewater , mechanical treatment , water treatment equipment , trash screen
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