Operations & Maintenance – Balance of Plant – Union Power Station

Water treatment improvements cut chemical costs by 10%

Union Power Station
Entegra Power Group LLC

Challenge. The plant obtains its water from a nearby river. The process of conditioning raw water for a 2200-MW combined-cycle facility included several steps—one being the introduction of a small amount of chlorine for biological control. Concerns about the long-term maintainability of this system led the plant staff to evaluate alternatives.

Solution. Working with personnel from GE Water & Process Technologies, Trevose, Pa, it was determined that use of sodium hypochlorite (bleach) as a biological control agent might be more economical and easier to handle than chlorine.

   A trial was conducted, and it was found that indeed the hypochlorite achieved the desired result. Permanent construction of a tank and delivery system to the pipeline feeding the raw water treatment plant was completed and the system placed into full time operation.

Results. After the hypochlorite system was installed, the plant steadily reduced chlorine addition to the point it was finally stopped. A further enhancement was needed to achieve small residual chlorine content in the finished water pumped to the powerplant, so a follow-up project was done to install a permanent hypochlorite injection system on it as well.

   The water treatment plant has operated over a year now with sustained improvement. Reduction of other chemicals at the water treatment plant was achieved as well as an unexpected side benefit. Overall chemical cost has decreased by over 10%, a significant dollar amount for a  facility of this size.