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UDC 628.33
Kuriatnikov E. A., El' A. M.
Unique design of settling tank covers at the Moscow wastewater treatment facilities
Summary
The problem of eliminating malodors emitted from wastewater is well known in world practice and is solved by isolating open surfaces at the treatment facilities from the ambient atmosphere with covers. The international experience of designing the covers for settling tanks to eliminate malodors is described. The specific features of different cover designs (domed, flat, floating), their advantages and drawbacks are considered. The design of PBI floating cover and the experience of using it on a 54 m diameter primary settler at the Liuberetskie Wastewater Treatment Facilities in Moscow are described. Floating cover for a sludge scraper basin has an original design developed by the «Moselektro» engineers which has nothing comparable in the international practice. The main advantage of PBI cover is the possibility of repairing the equipment installed inside the settling tank eliminating complete cover dismantling. PBI cover has the minimum ventilation space that provides for the significant savings because of the low power consumption of the air cleaning system. PBI covers of any diameter can be installed on the storage tanks at the treatment facilities without any modifications of the building part. The results of the process and durability tests of the sludge scraper of new design that ensures the maximum stiffness and integrity of the system are presented.
Key words
sludge scraper , sewerage treatment facilities , primary settler , domed covering , floating cover , flat cover
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UDC 628.32:62-192
GALPERIN E. M., Komarov D. S.
On integrity and maintenance of sewers
Summary
The issues of the integrity and maintenance of gravity sections of sewers are discussed. The pipelines (water, heat and gas) of the municipal utility infrastructure are characterized by pressure flow of the work product. Depressurization in such pipelines causes failures. Determining the initial stage of a gravity sewer failure is very difficult; therefore minor pipe leakages under small pressure can continue for prolonged periods. This fact requires sewer regular maintenance to ensure its integrity. However, the regulatory documents in many cases do not take into account the operation experience. Main sewer failures are blockages and structural damages. To reduce the number of blockages it is suggested to increase the minimum diameter of outdoor sewer pipes to 200 mm. To improve the conditions for sewer repair draining of pipes is recommended. A layout of installing a permanent bypass for sewer section draining for inspection, maintenance and repairs is suggested. Relatively small length of the drained sections (150–200 m) will provide for laying bypass pipe with significant fall eliminating excess digging in so that high liquid velocities and flows are ensured, and reduced bypass diameter and energy saving are predetermined. Permanent bypasses provide for high quality maintenance that in the long run extends the service life of the facilities.
Key words
reliability , maintenance , gravity sewer , draining , bypass installing , inspection , repair work
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UDC 628.171.033
Shmigol V. V., Chernosvitov M. D., Kukolkin V. N., Polst'ianov V. N.
The prospects of improving the energy efficiency of boosting pumping stations
Summary
«Samarskie kommunal’nye sistemy» LLC has been providing cold water supply, wastewater collection and treatment on the territory of the Samara urban district. One of the main tasks of the enterprise is improving the energy efficiency of boosting pumping stations. For this purpose a comprehensive approach to the selection of the number and trademark of pumping units as well as to the practicability of installing variable-speed drives is required. In contrast to the projected pumping stations with calculating the duty cycle of the pumps, with the existing stations solving the problem of minimizing wasteful energy losses requires studying the established water consumption pattern; determining the required pressure at the pumping station outlet and available pressure in the municipal distribution network. The problem of maintaining optimal pressure at the boosting pumping station outlet shall be considered: constant maximum design pressure; changed as per schedule; depending on the flow rate. Arranging a complete water audit, identifying illegal water consumers and optimizing the operation of block pumping stations with the use of variable-speed drives will provide for the significant reduction of water and energy consumption. The comparison of the dynamics and specific water consumption in separate residential buildings with the operation of the block boosting stations supplying water to separate residential buildings and blocks and with the existing regulation is presented. The diagrams of the specific water consumption patterns and variations in water consumption within 24 hours are given. The conclusions related to the prospects of improving the energy efficiency of the boosting pumping stations operated by «Samarskie kommunal’nye sistemy» LLC are drawn.
Key words
losses of water , energy efficiency , pumping station , unaccounted-for water , specific water consumption , water consumption variation
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