The most interesting alternative from my point of view - to create a closed ecosystem. So some kind of shrimps eating of algae, or some kind of small fishes eating of algae and shrimps. This may be the practice object for the biological college students.

We have tested with success a bacterial control media coated on sand particles. Result: elimination of the oxidizing biocides (bromine) in cooling towers with excellent control of bacteria counts, Legionella and slime forming bacteria. The advantage of this is that the water is filtered and bacteria suppressed at the same time (in the same vessel). I would be happy to send you more on the tests.

There is a non-chemical water treatment system that utilizes Pulsed Electric Fields to control Biological growth, Scale formation and Corrosion and could run at higher cycles of to save additional water. We have over a thousand of these units all over North America including multiple data centers. Please visit www.evapco.com and look for the Pulse~Pure system or feel free to email me and I can get you in contact with our local office in your area & you might be able to visit a site with a Pulse~Pure in operation.

Too late now if you've already installed cooling towers. Next time maybe you can consider Jaeggi hybrid coolers, which provide closed circuit cooling with the same wet bulb efficiency as cooling towers. But because they operate dry for most of the year, and only use hybrid/wetted mode when necessary during higher ambient temperatures, they will save 80-90% of annual water consumption = 80-90% of biocide chemical consumption and water treatment = 80-90% less blowdown. So significantly reducing operating and maintenance costs compared to traditional cooling towers. Alternatively, due to the cooler design and operation, UV lamps are a proven effective alternative to conventional biocides - giving chemical-free cooling.
They also are neighbor-friendly with no visible vapour plumes and no emissions of water droplets or aerosols (i.e. no drift), so are also legionella-safe. Proven Swiss design, used in major data centers all over Europe and available in the USA via Jaeggi US. See www.jaeggi.us for USA and www.jaeggi-hybridcooler.com for English language European web page.

There is a good Chemical Free system called XTech, Call Liquitech in Chicago Ill, Phone: 306-693-0042 Ask for Steve Schira. They have several systems running in European and US data centres, No chemicals, increased COC, and no issues with blow down.

regards
Xander

Check these folks out: http://www.clearwater-dolphin.com/market_research.htm

There is a new technology for cooling tower water treatment which has been embraced by such corporate Data Centers on the West Coast as: Google, Microsoft and Yahoo.

In NJ the Sentinel NJ1 Data Center in Somerset NJ is currently utilizing this technology which is completely green and sustainable. There will be no problem with biocides in the tower bleed!!!

Please feel free to contact me at your convenience and we may discuss your application and this technology further.

Thanks,

Andrew R. Dougherty
Chief Engineer
Advanced Water Treatment
e-mail: awt2001@rcn.com