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POREFLON Microfiltration Membrane Module

Home > Application Example 2: Wastewater Treatment at Steelworks in China

Application Example 2: Wastewater Treatment at Steelworks in China

Background

Wastewater discharged from the cold rolling process at steelworks contains a high level of oil components such as lubricants and emulsifiers. One Chinese steelworks had been using conventional methods to treat wastewater and discharge it into the nearby river. Since in China water quality regulations applicable to discharged wastewater have become increasingly tight, conventional wastewater treatment is no longer permissible.

Objective

To meet the increasingly tight water quality regulations, the steelworks made the decision to introduce a new wastewater treatment system.

Challenge

The steelworks planned to adopt a membrane bioreactor (MBR) to improve the quality of treated water and evaluated membranes made from some other materials. Since the wastewater from the cold rolling process in steelmaking contains oil, they experienced problems such as the membrane becoming clogged with oil and it becoming impracticable to clean the clogged membrane. These problems raised concerns about long-term stable operation of MBR. In the meantime, Sumitomo Electric had been conducting long-term field tests using MBR on similar wastewater at another steelworks. This customer remarked that MBR had proved to be usable without any problems and the evaluation results had been favorable. Although we did not know it, the two steelworks were in partnership with their wastewater treatment technology, so the first steelworks also tested our products and gave it high marks. Consequently, they adopted our product and found that Sumitomo Electric's membrane performs stable filtration of oil-contaminated wastewater and can be cleaned with a high concentration of alkali.

Results

Although not many of them had been used to treat wastewater from the cold rolling process in steelmaking, the result of introducing MBR was a finer treatment than the existing method that complied with the water quality regulations. More specifically, oil contained in the raw water decreased from some 100 mg/L to 5 mg/L or less. Although it had been thought to be too difficult to remove oil using a membrane, POREFLON Membrane Module has achieved that difficult task.

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