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UDC 628.1.2:62-278

Frenkel V. S.

Membrane Technologies: Past, Present and Future (the North America as an Example)

SUMMARY

Basic tendencies in the field of development of membrane processes for water and wastewater treatment in the North America are covered. Main characteristics, basic trends and features of the use of membranes including membrane bioreactors are presented. Characteristics necessary for assessment and selection of the best membrane technologies for each certain project are compared. Membrane treatment has become the fastest growing sector in water treatment, wastewater treatment and water desalination. Four types of membranes are used according to membrane pore size: microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO). All four principal types of membrane guarantee the removal of the entire spectrum of water pollutants and can be used as a stand-alone technology for a majority of applications. Integrated membrane processes combining different membrane types are becoming a cutting edge approach to meet strict water/wastewater quality regulations because they allow the smallest possible system size, minimize chemical consumption, and provide the most cost-effective solution for the greatest number of applications.

Key words

potable water , wastewater treatment , reverse osmosis , ultrafiltration , desalination , membranes , microfiltration , nanofiltration , membrane bioreactor

UDC 628.165:66.081.6
DOI 10.35776/VST.2024.06.03

Babenko Kirill, Kagramanov Georgii, Бланко-Педрехон А. М.

Desalination of sea water: trends, experience and development prospects in the Russian Federation

Summary

Fresh water is a limited and unevenly distributed resource. Despite significant fresh water resources, some regions of the Russian Federation experience a shortage of it, which affects the dynamics of the economic development and living standards. This fact requires a revision of the classical approach to the environmental management, in particular, to the extraction of fresh water from sea and brackish waters. The most common desalination technologies are thermal (distillation) and pressure membrane (reverse osmosis and nanofiltration) processes. Over the past quarter century, reverse osmosis has become the predominant water desalination technology, accounting for more than 70% of all production capacity in the world. Nevertheless, reverse osmosis has a number of significant limitations, the consideration of which while designing desalination plants is a prerequisite for the subsequent efficient and reliable operation of the facilities. Strict requirements for the quality of source water supplied to reverse osmosis membranes necessitate the use of complex and often multi-stage seawater pretreatment systems. The choice of technical solutions for pre-treatment and «architecture» of reverse osmosis plants is the subject of a comprehensive technical and economic analysis with account of local aspects, including the region of construction, its natural and climatic conditions and available infrastructure. The shortage of water resources and the climatic and oceanological conditions of the coastal regions of the Russian Federation atypical for the global desalination industry make the solution to this optimization problem relevant and appropriate.

Key words

reverse osmosis , desalination , membranes , desalination , sea water , fresh water , distillation , pretreatment

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UDC 628.165:66.081.63

Chigaev I. G.

The use of nanofiltration in brackish water softening

Summary

The results of the experimental studies with real water are presented that showed the perspectiveness of using the purification techno­logy based on polymer nanofiltration membranes in underground brackish water desalination as compared to reverse osmosis. The basic characteristics of nanofiltration membranes were studied. Possible concentrating of influent water by partial concentrate recycling was evaluated; the maximum salt concentrations in recycling water were determined. The studies on evaluating the effect of deposit formation on the basic membrane characteristics did not discover any noticeable permeability reduction; herewith the zones of intensive salt deposit formation on membranes were identified. It was determined that salt concentration in recycling water supplied on the membrane shall not exceed 42 mg-equ/l to obtain permeate with up to 6 mg-equ/l and for permeate with 2 mg-equ/l hardness the salt concentration shall not exceed 18 mg-equ/l. Influent water concentrating provides for the substantial reduction of discharged concentrate.

Key words

reverse osmosis , membranes , nanofiltration , desalination , underground brackish water , deposit formation

DOI 10.35776/VST.2022.12.06
UDC 621.395.623.3

Strelkov A. K., Tsabilev O. V., Gridneva M. A.

Vibromembrane filtration technology: eliminating the negative effect of concentration polarization (international experience)

Summary

Представлена уникальная технология мембранного разделения жидкостей VSEP, которая позволяет минимизировать негативное влияние концентрационной поляризации. Отличие технологии заключается в вибрации поверхности мембран. В результате достигается ряд ключевых преимуществ технологии. Все это существенно раздвигает границы использования мембранных методов и делает возможным применение мембран там, где ранее это было невозможно. Кроме того, процесс разделения различных жидкостей не требует использования антискалянтов, а рабочие значения удельной производительности установок и выхода фильт­рата значительно превышают таковые в традиционных системах мембранного разделения. Технология уже находит массовое применение в мировой инженерной практике для самых различных отраслей промышленности.

Key words

membranes , nanofiltration , membrane filtration , VSEP technology , concentration polarization