Dual-membrane technology enables blow down reuse in Gaojing power plant

MINNEAPOLIS, MN, Aug. 20, 2009 -- Facing increased environmental regulations from the Chinese government in 2003, the Gaojing Power Plant enlisted DOW Ultrafiltration modules and FILMTEC brackish water reverse osmosis elements as a solution for reuse using the blow down from their cooling towers as boiler feed water...

MINNEAPOLIS, MN, Aug. 20, 2009 -- For the past 40 years, the Gaojing Power Plant has supplied heat and electricity to its local communities and industries. Facing increased environmental regulations from the Chinese government in 2003, the plant enlisted DOW™ Ultrafiltration modules and DOW™ FILMTEC™ brackish water reverse osmosis elements as a solution for reuse using the blow down from their cooling towers as boiler feed water.

"Water recycling systems for cooling tower blow down have become more common in fossil fuel power plants because of the large volume of wastewater needed," said Kelvin Cheung, strategic marking manager for Dow Water & Process Solution. "Coupled with the proper pretreatment and chemical dosing, DOW Ultrafiltration modules and FILMTEC membranes help eliminate problems in subsequent wastewater reuse systems."

Located in Mengtougou and constructed in the 1960s, Gaijing is one of the earliest power plants built by Datang Corporation in Beijing. Traditionally, the source of the cooling tower makeup was from surface water, but was changed to secondary effluent from the Gaobeidian Municipal Wastewater Treatment Plant in 2007. Due to the wastewater's concentration, contaminants varied substantially with seasons and cooling tower makeup quality.

Dow Water & Process Solutions' dual-membrane technology was able to overcome a waste stream containing high hardness, alkalinity, silicon dioxide and sulfate, typical in cooling water blow down to help the power plant meet increasing environmental requirements from the government. The integrated technology, together with proper pretreatment and chemical dosing, helped the plant to realize more than 70 percent reuse of the cooling tower blow down -- even after five years of operation.

This dual-membrane solution consists of DOW™ Ultrafiltration SFP-2660 and DOW™ FILMTEC™ BW30-365FR and BW30-400 reverse osmosis membranes. To learn more about Dow Water Solutions' innovative solutions, or view this case study in its entirety, visit www.dowwatersolutions.com.

About Dow Water & Process Solutions
Dow Water & Process Solutions has a 50 year legacy of providing innovative water and process solutions to both communities and industries alike. A differentiated business unit of The Dow Chemical Company, Dow Water & Process Solutions offers a broad portfolio of ion exchange resins, reverse osmosis membranes, ultrafiltration membranes and electrodeionization products, with strong positions in a number of major application areas, including industrial and municipal water, industrial processes, pharmaceuticals, power, residential water and wastewater and water reuse. More information about Dow Water & Process Solutions can be found at www.dowwatersolutions.com.

About Dow
Dow is a diversified chemical company that combines the power of science and technology with the "Human Element" to constantly improve what is essential to human progress. The Company delivers a broad range of products and services to customers in approximately 160 countries, connecting chemistry and innovation with the principles of sustainability to help provide everything from fresh water, food and pharmaceuticals to paints, packaging and personal care products. In 2008, Dow had annual sales of $57.5 billion and employed approximately 46,000 people worldwide. The Company has 150 manufacturing sites in 35 countries and produces approximately 3,300 products. On April 1, 2009, Dow acquired Rohm and Haas Company, a global specialty materials company with sales of $10 billion in 2008, 98 manufacturing sites in 30 countries and approximately 15,000 employees worldwide. More information about Dow can be found at www.dow.com

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