Introduction of membrane technologies at the wastewater treatment facilities of Molodezhnoe settlement

Summary

The experience of introducing membrane wastewater treatment technology at the wastewater treatment facilities in Molodezhnoe settlement (St. Petersburg) is presented. The treatment facilities include: a main pumping station, a combined mechanical wastewater treatment plant, a wastewater regulator, a bioreactor (aeration tank operating using nitri-denitrification technology) for enhanced nitrogen removal, a membrane bioreactor, an ultraviolet effluent disinfection unit, a screw press for excess activated sludge dewatering, aluminum sulfate dosing unit for the chemical removal of phosphorus compounds (phosphates). The effluent after disinfection is discharged through a deep-water outlet into the Gulf of Finland. Membrane filtration provides for the enhanced tertiary treatment to remove fine suspended solids and colloidal particles. To achieve a stable quality of the effluent during the operation of membrane modules, the following requirements shall be strictly met: the high efficiency of screenings removal; prevention of the ingress of foreign particles into the bioreactor after mechanical treatment; high concentration of sludge in the aeration tank and membrane unit; timely chemical washing of the membranes. During the trial operation of the treatment facilities in Molodezhnoe, the irregular hydraulic and pollution loading was noted. During the operation period the operating modes of the facilities were adjusted with account of the irregular characteristics of the incoming flow while achieving the design parameters of the process line of wastewater treatment.

Key words

wastewater , advanced biological treatment , transmembrane pressure , membrane module , membrane technology , hydraulic loading

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UDC 628.34:66.081

Maiboroda A. B., Katraeva I. V., Kolpakov M. V.

Effluent polishing with the use of ultrafiltration

Summary

The results of investigating the removal of phosphate ions and suspended solids that enhance eutrophication of water bodies from biologically treated domestic wastewater after secondary settling tank are presented. Experimental studies of effluent polishing with the use of ultrafiltration technology in combination with coagulation were carried in the laboratory of the Nizhny Novgorod State University of Architecture and Civil Engineering. The aluminium hydroxychloride dosage of 20 mg/l as Al2O3 was used as a coagulant. Hollow-fiber module manufactured by Fazerkraft Russian Company with polyvinylidenefluoride was used for tangential ultrafiltration in cycle mode. The membrane module is a device with a cylindrical shell with a bunch of hollow fibers inside with porous walls. The impact of transmembrane pressure on the filtration process was investigated. It was found that the specific flow rate of permeate increases with the increase of transmembrane pressure within the range of 0.05–0.2 bar. The tests showed that 20-fold increasing the concentration of the suspension subject to treatment does not result in any significant decrease of permeate production of the membrane module. Increasing recycling rate (of tangential flow) results in the increase of permeate flow; however, on account of technical and economic aspects, the range of low recycle flow values is of most interest. The results of the studies showed that the suggested ultrafiltration technology provided for almost complete elimination of suspended solids (more than 93% treatment efficiency), 97% reduction of phosphates in wastewater, and reduction to 0.04 mg/l aluminium concentration in permeate.

Key words

suspended substances , membrane module , wastewater aftertreatment , phosphates , ultrafiltration

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UDC 168.165

Tsabilev O. V., Strelkov A. K.

Optimization of the scheme of preparing demineralized water at the existing machine building enterprise

Summary

Machine building industry needs demineralized water for moisturizers, washing and other processes. To prepare demineralized water the method of reverse osmosis is used. The advantages of this method of water demineralization are as follows: low chemical consumption, compact size of the plants and possible flexibility of the process automation. Considering the scale of reverse osmosis use and diversity of the solvable problems designing a versatile installation meeting all the requirements is practically impossible and economically unjustified. It is evident that engineering calculations and design adaptation shall be carried out in each case. An example of upgrading the demineralization scheme with the purpose of improving the capacity and conditioned water quality is presented. The result is achieved by the use of the two-stage reverse osmosis scheme that provides for the minimum chemical costs during the operation. The modernization of the facilities was carried out in continuous-duty service. Half year operation of the upgraded two-stage scheme the sustained quality of the demineralizaed water has been observed.

Key words

reverse osmosis , membrane module , permeate , two-stage scheme , water demineralization

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UDC 628.33:62-278

KOZLOV M. N., Nikolaev Yu. A., Khramenkov S. V., Kharkina O. V.

Perspectives of Introduction of Membrane Technique at Treatment Facilities of Moscow

Symmary

Studies of the membrane technique of treatment of low-concentrated municipal wastewater at a pilot unit of up to 5 m3/day capacity have been carried out. As a result, high quality of treated water concerning suspended particles and biogenic elements has been obtained, resistance to volley entries of industrial wastewater and high efficiency of water disinfection have been reached. Results of pilot tests have made it possible to appreciate the membrane biotechnologies as perspective for realization at Moscow treatment facilities. Advantages of the technology with the use of membrane bioreactors: considerable reduction in volumes of facilities and spaces occupied by them owing to the high concentration of activated sludge, possibility of a higher load per a volume unit and also significant decrease in quantity of excessive activated sludge. Membrane bioreactor technologies are one of the perspectives of development of treatment facilities under the conditions of limited areas.

Key words

wastewater , bioreactor , hydraulic condition , biological removal of nitrogen and phosphorus , membrane module

UDC 628.161:66.081.63
DOI 10.35776/VST.2024.03.07

Barsukov Oleg, Larionov S. Iu., Panteleev Aleksei, Riabchikov Boris

Ways to reduce fouling of separation membranes and increase the performance of membrane apparatus (a review)

Summary

The widespread use of membrane technologies in the energy sector in water purification processes, wastewater treatment and other areas poses questions of their improvement in order to increase the economic efficiency, performance of membrane separation apparatus, reduce the amount of secondary waste, etc. Potentials are being sought to improve these indicators. Moreover, if the highest level has currently been reached in the development and production of membranes, and no further dramatic improvements are visible so far, then in relation to the design it is believed that there are still potentials. The paper discusses options for increasing the efficiency of membrane separation apparatus by means of the external effects on the processed water or on the membrane apparatus. This is the pulsation of the liquid flow, ultrasonic impact on it, rotation of special inserts or the membranes themselves, vibrations of the membrane element. The complexity of their design and the prospects of application for different stages of purification and concentration processes are estimated.

Key words

membrane module , membrane technology , concentration polarization , reverse osmosis and nanofiltration plants , separating diaphragms , LF oscillations , ultrasonic waves , rotation , membrane vibrations , Roсhem apparatus , New Logic Research , VSEP system