Membrane Ozonation of Waste Waters
Ozone Pertraction through Non-Porous Polymeric Membranes for Efficient and Energy Saving Treatment of Waste Waters and Disinfection of Drinking Water
Tech Area / Field
- ENV-WPC/Water Pollution and Control/Environment
8 Project completed
Senior Project Manager
A.V. Topchiev Institute of Petrochemical Synthesis, Russia, Moscow
- VNIIEF, Russia, N. Novgorod reg., Sarov\nKurchatov Research Center, Russia, Moscow
- Compact Membrane Systems, Inc., USA, DE, Wilmington\nKanzler Verfahrenstechnik Gesellschaft m.b.H, Austria, Graz\nCranfield University, UK, Silsoe\nIstituto di Ricerca su Membrane e Modellistica di Reattori Chimici, Italy, Arcavacata di Rende
The objective of the project is the development of novel technology of wastewater ozone treatment with the aim of increasing efficiency and reduction of energy consumption and equipment cost for wastewater treatment and disinfecting of potable water. More specifically, the objectives of the project are to develop the membrane systems for injection of ozone in the streams to be treated in order to obtain substantially larger mass transfer coefficients as compared with the existing systems (bubble columns). It is planned to evaluate the efficiency of such systems for the treatment of wastewater containing phenol and other pollutants, for disinfecting of municipal effluent streams and river water in order to remove harmful bacteria and viruses. A removal of trace concentrations of fluorine and chlorine containing pollutants, as well as of dioxins from such effluents is also most desirable.
Industrial growth and increases in the quantities of municipal waste effluent streams require development of efficient, cost and energy saving methods of treatment of liquid wastes and pretreatment of potable water. It is important that environmentally undesirable effects should not accompany these methods. In this regards, the chlorinating methods, which are now in a wide use, should be replaced soon by environmentally more friendly ozone treatment methods. The main drawback of ozonization is related to great energy consumption in ozone generation, which cause large running cost of the process. An additional difficulty is induced by relatively low solubility of ozone in water: this results in marked losses of ozone in the process of treatment and, hence, to further increases in energy consumption. Today, as can be judged by an analysis of the literature, there is no acceptable technical solution of this problem.
A technical idea on which the project is based consists of injection of ozone in the media to be treated through polymeric membranes (pertraction method). When penetrating through non-porous membranes in the process of pertraction gas gets into the liquid phase in the form of inpidual molecules, not bubbles like in injector systems or bubble column, so the conditions of its equilibrium dissolution are achieved. Due to it, an efficiency of the ozone dissolution is increased and the losses of ozone are reduced.
For realization of this technology, high flux ozone penetration membranes are needed and, in addition, their material should be stable in long term contact with ozone. Recently, one of the participating groups (Institute of Petrochemical Synthesis) has been studying membrane materials, which show the necessary complex of properties, namely, amorphous glassy copolymers of substituted perfluorodioxole and tetrafluoroethylene. They were shown to be extremely chemically stable and have extraordinary large gas permeability, by 2-3 orders larger than those of conventional glassy polymers. In addition, they are soluble in common perfluorinated solvents, and it opens a possibility to manufacture membranes on the basis of conventional solution technology. Indeed, preliminary results obtained in a group from Kurchatov Institute showed that the composite membranes formed from these polymers using porous hollow fibers as supports revealed oxygen permeance as large as 7 m3(STP)/m2 h atm, what can be considered as an unparalleled high flux.
Thus the specific aims of the project are as follows:
- Development of high flux and stable membranes suitable for injection of ozone in perse liquid effluents to be ozonated (treated) by pertraction;
- Development of new type of membrane contactor based on this principle;
- Investigation of the ozonation processes of different model solutions and industrial wastewater as well as disinfecting of natural waters with the aim of obtaining potable water, which would satisfy existing sanitary norms; formulation of the recommendations for industrial unit, its optimal scale and fields of application.
The participants have sufficient experience and competence for realization of this project Thus, the project manager, Professor Yu.Yampolskii, is an acknowledged specialist in membrane gas separation. In his Laboratory of membrane gas separation in TIPS, systematic works are being performed in development of new membrane materials. Another participant of the project, Dr.E.Krasheninnikov is known by his works on development of membranes, membrane modules and systems for solving different gas separation problems. In his laboratory in RSC KI, original methods of formation of composite, hollow fiber, high flux membranes were developed. They found applications for separation of various gas mixtures. Dr.V.Shiryaevskii from the same Institute has big experience in creation of ozonizers and their use for solving different environmental problems, e.g. potable water pretreatment, wastewater treatment, etc. At last, Dr.L.Vinogradskii has been engaged in long term studies of chemical analysis of different gas and liquid streams. The laboratory headed by him in RFNC is equipped with different instruments for chemical analysis, for control of composition and quality of drinking water and wastewater. He has a big experience in various methods of purification. This equipment will be quite useful for monitoring the processes of ozonation of various streams. It is also important, that special containers for storage and transportation of different model liquids are available, which keep the composition of the liquids unchanged.
It can be expected that, as a result of project completion, the novel technology will be created and tested – membrane ozonation of wastewater and natural waters. Its aim is a reduction of investments and energy consumption in water treatment plants and partial replacement of chlorinating processes by more environmentally friendly ozonation processes.
A commercial potential of the proposed project is high; a wide and persified expansion of new technology could take place. A fundamental interest to the proposed project can be related to the fact that today very little is known on transport parameters of ozone in polymers (permeability, diffusion, and solubility coefficients) and on the work of membrane ozonation reactors.
Two groups of participants connected in past to weapon (defense) research will take part in the project: the one from RSC KI and another from RFNC. The participation in the project will enable them to collaborate with the specialists from Russian academy of sciences, carry out joint research with them and interact with foreign collaborators. The international group of collaborators in this project manifests an interdisciplinary character of the research work planned. They include as industrial companies as universities, the specialists in polymer science, membrane technology, and ecology – ozonation, wastewater treatment, and environmental protection.
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