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UDC 628.321
Riabchikov Boris, Larionov S. Iu., Panteleev Aleksei, Shilov Mikhail
The study of enhanced water coagulation with the use of microsand
Summary
The results of the analysis of the present day advanced water coagulation equipment are presented. The results of the study showed that using the systems with sludge recycling and microsand addition was the most efficient solution. Because of the lack of reliable data on the efficiency of the given equipment, operational mode and chemical consumption, experimental units were designed that provided for testing the required modes and significant improving the process. Using sand from a packed column equipped with airlift for washing produced good results. Sand loss was less than 1%. In the process of the experimental studies it was shown that the effect of fast precipitation in the clarifier at high linear water flow rate was possible. However, the use of static chemical mixing systems does not provide for the sustainable unit operation with changing parameters – flow rate, stock solution concentration, and temperature. For that reason the unit was upgraded following Actiflo option with the use of mechanical mixers for mixing with chemicals and sand, however, with sand and sludge separation in the plate column equipped with a pulsation system to improve the wash efficiency. The designed flowsheet of sludge separation into microsand and sludge with the help of a packed column showed significant advantages compared to the system with hydrocyclones. On the basis of the obtained data terms of reference for designing a pilot unit were developed.
Key words
potable water , hydrocyclone , coagulation , microsand , flocculation , static mixer , wash column
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UDC 628.349
Adel'shin A. B., Adel'shin A. A., Grishin B. M., Bikunova M. V.
Oilfield wastewater treatment with the use of centrifugal apparatuses
Summary
The task of the studies was improving the efficiency of polydisperse oil particles removal from oilfield wastewater. The process is complicated with the presence of adsorption (inhibiting) shells of mechanical impurities on fine-dispersed oil droplets. A new technology of oilfield wastewater treatment is suggested that provides for wastewater pretreatment in hydraulic cyclones equipped with cylindrical (tubular) overflow chambers that allow stimulating the processes of oil droplets coalescence. The flow sheet of a pilot plant for studying the processes of emulsified oil droplets growth is presented. The plant comprises a hydraulic cyclone connected to the upper and lower overflow chambers. Oilfield wastewater of «Tatneft» OJSC was chosen as a test subject (oil concentration 710–800 mg/l). It was stated that the coalescence efficiency was determined by the vortex value parameter in overflow chambers and by the time of wastewater treatment in the centrifugal field. Processing the test results on the oil droplet size distribution showed that the optimal vortex parameter values for the upper overflow chamber of the hydraulic cyclone were within 20–23; whereas for the lower overflow chamber – 16–18.5. The recommended time of wastewater treatment in the upper and lower overflow chambers was relatively 24.5 and 18.5 seconds. It was experimentally determined that the residual oil concentration after oilfield wastewater treatment in the hydraulic cyclone and two hours sedimentation was less than 72 mg/l at 91% treatment efficiency. It was 6% higher compared with the wastewater sedimentation efficiency after treatment in the hydraulic cyclone only. The design of BGTO plant (hydraulic cyclone block – overflow chamber – sedimentation tank) is suggested that provides for the efficient treatment of oil effluents on industrial scale.
Key words
settling , hydrocyclone , oil effluents , oil droplet coalescence , overflow chamber , treatment plant
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UDC 628.334
Shchetinin A. I., Marchenko Yu. G.
Up-To-Date Equipment and Facilities for Mechanical Treatment of Wastewater from Coarse-Disperse Admixtures
Summary
Up-to-date equipment for wastewater treatment from coarse-disperse admixtures is considered. Designs of screens are described briefly, their advantages and shortcomings are presented. Formulas for calculation of head loss on sreens are presented. Recommendations to install screens with openings not less than 5 mm are made. The comparative analysis of different methods of sand-catchers design shows that the normative time of stay in sand catchers can be extended up to 10 minutes. Literary data treatment has made it possible to obtain formulas offered as a new calculation base for determination of efficiency of horizontal and aerated sand catchers during the designing. Up-to-date equipment for sand collection and removal is considered.
Key words
wastewater , mechanical treatment , hydrocyclone , aeration tank , screens , sand catchers
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