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Latest Information 2015 Vol. 458

Development and sale of large-size membrane module for wastewater treatment

Sumitomo Electric has developed a large-size membrane module constructed of polytetrafluoroethylene (PTFE) hollow fiber membranes*1 for membrane bioreactor*2 (MBR) applications.

In a membrane bioreactor, which is a typical wastewater treatment system that uses membranes, membranes are sunk into a microbe (activated sludge) tank to filter microbes by absorption. In most bioreactors, the membranes are continuously oscillated by aeration (air-bubbling) to prevent their contamination by microbes. However, aeration consumes a large amount of electrical energy.

The newly developed membrane module constructed of PTFE hollow fiber membranes is highly elastic and easy to oscillate, and it is not contaminated so easily by microbes. The new membrane module is 8 to 10 times stronger than membrane modules constructed of a single type of hollow fiber from other materials. The high flexibility and strength of the new module has made it possible to increase the maximum membrane length from the conventional 2 m to 3 m, thereby increasing the oscillation amplitude of the module and dramatically improving its self-cleaning power. In addition, the filtration area per module increases to a maximum of about 60 m2 by densely arranging the new membrane modules.

Owing to the advantages described above, the new membrane module reduces the aeration air quantity per unit quantity of wastewater to be treated and also saves electrical energy by more than one-third of the conventionally consumed energy. Further, the new membrane module reduces the treatment system installation area per unit quantity of wastewater to be treated to about two-thirds of the conventionally required area, thereby reducing the initial costs, such as the microbe tank construction cost and piping material cost. The Japan Sewage Works Agency’s one-year study on the membrane bioreactor process has verified that the new membrane module can reduce the total energy including aeration energy necessary for treating 1 m3 of wastewater to 0.4 kWh/m3 (target value for promoting the spread of MBR) or less.

Sumitomo Electric will introduce large-size membrane modules that can treat wastewater at lower cost into the global market of wastewater and other effluent treatment systems (membrane bioreactor) in order to further expand the company’s water treatment business. In addition to South Korea, Taiwan and China, in which we have focused on sales of our water treatment systems, the company will expand its sales network to other regions including North America and Southeast Asia.

Effluent treatment modules (membrane length: 3 m) used for the demonstration test conducted by the Japan Sewage Works Agency
Effluent treatment modules (membrane length: 3 m) used for the demonstration test conducted by the Japan Sewage Works Agency
Example of use (conventional product)
Example of use (conventional product)
*1
Hollow fiber membrane: A filter constructed of thin hollow fibers whose surfaces contain many minute pores.
*2
Membrane bioreactor process: A process for treating effluent containing mainly organic substances. This process uses microbes (activated sludge) together with membrane modules. The former degrade organic substances dissolved in the effluent, while the latter separate the microbes from solids contained in the raw effluent.
Water Processing Division

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