In response to stricter effluent regulations, the 107-bed Pomerado Hospital in Poway, Calif., was looking for an alternative to the traditional chemicals it was using to treat scale, corrosion, and bacteria in its 600-ton cooling tower. After examining options from several vendors, the hospital chose a non-chemical treatment system from VRTX Technologies.
“We felt that it gave us the greatest benefits, including sound, proven technology that we could see working in other facilities and a simple payback that fit into our capital-improvement expectations,” Facility Manager Jonathan Huls said.
Installed in January, the system consists of a 40-gpm skid-mounted unit that includes a 150-gpm centrifugal separator/cartridge filter. The installation also includes sweeper nozzles in the cooling-tower basin.
HOW IT WORKS
The VRTX system consists of two side-stream loops connected to the sump. The nozzle design forces opposing water streams to collide with tremendous kinetic energy, creating millions of bubbles that form and collapse. This provides enough energy to change water quality. Controlled hydrodynamic cavitation precipitates mineral colloid bonds, which are removed via a side-stream filtration loop.
A strong vacuum (27.5 to 29.5 in. Hg) at the collision zone strips dissolved carbon dioxide from the water to maintain the potential of hydrogen (pH) in an alkaline environment. The cavitation process has dramatic effects on bacteria. High localized temperature during bubble collapse kills bacteria as pressure and high-velocity microjets perforate the microbial cell structure.
Because suspended solids are dropped from solution, water can be recirculated more often than with traditional chemical treatment. By increasing the cycles of concentration or the number of times water passes through the system, Pomerado Hospital is saving water at a rate of 2 million to 3 million gal. annually.
The installation has yielded several positive results, including:
Performance that has met or exceeded what would have been accomplished with conventional chemical water-treatment methods.
Elimination of the use of hazardous chemicals. Worker safety has been improved, training requirements have been reduced, and on-site water-treatment-chemical storage has been eliminated.
Elimination of scale buildup.
Microbiological control that has averaged less than 1,000 cfu per milliliter.
The generation of more than 2 million gal. of non-potable water for reuse on an annual basis.
An added benefit for the hospital has been cooling-water reuse. Because the water coming from the cooling tower at Pomerado Hospital does not contain chemicals, the water can be contained for landscaping, equipment washing, or any other non-potable application.
“The team at VRTX has provided us with excellent customer service while also providing us with a non-chemical cooling-tower treatment, which has eliminated chemicals from being discharged into the sewers and helped us lower our water usage,” Huls said. “The VRTX is working great — it is maintaining our biological and scale buildup well below normal expected levels. The system is simple and easy to maintain, even through the harsh construction conditions in which it has operated.”
VRTX's success at Pomerado Hospital has prompted owner Palomar Pomerado Health System to consider the system for its new Palomar Medical Center in Escondido, Calif., which is slated to open in 2012.
Information and image courtesy of VRTX Technologies.
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