Pulsed-power water treatment
Pulsed-power water treatment is the process of using pulsed, electro-magnetic fields into cooling water to control scaling, biological growth, and corrosion. The process does not require the use of chemicals and helps eliminate environmental and health issues associated with the use and life-cycle management of chemicals used to treat water. Pulsed-power systems have the ability to maintain low levels of microbiological activity without using corrosive chemicals. Several reports have shown that pulse-powered systems yield significantly lower counts of bacteria colony forming units compared to chemically controlled systems.
Overview and uses
Pulsed-power systems are used to control scale, corrosion and biological activity in cooling towers without the use of chemicals, chemical tanks or pumps. Pulsed-power has been used as the sole source of water treatment in cooling systems for over a decade now with good results. The pulsed-power imparts electromagnetic fields into the cooling water and the induced fields have a direct effect in preventing mineral scale formation on equipment surfaces and controlling microbial populations to very low levels while also significantly reducing biofilms present in cooling systems. One example of pulsed-power water treatment is Dolphin WaterCare products produced by Clearwater Systems. It is a patented technology used to treat water for cooling towers, chilling systems, heat exchangers, direct evaporative coolers, and hot water systems. These systems are also used in numerous studies of pulsed-power treatment systems.
Pulsed-power is also an FDA approved method for pasteurizing fluids such as fruit juices. However, the energy needed for pasteurization is 100 times that of a pulsed-power water treatment system.
Pros and cons
Pulsed-power treatment enables chemical-free treatment of cooling tower water while providing lower bacterial contamination as it controls scale and corrosion. The cost over the lifetime of use is lower than that of chemical treatment and also reduces the health concerns of handling chemicals. Cycles of concentration are typically increased which reduces blowdown water. The resulting elimination of chemicals provides many benefits including reduced EH&S risks, environmental benefits of reusing blowdown water and elimination of chemical-laden discharge water. Pulse-power treatment is less effective on water that is extremely soft or distilled as the technology is based on changing the way minerals in the water precipitate. It also still requires energy to use.
- "Pulse-Powered Chemical-Free Water Treatment" (PDF). American Society of Heating, Refrigeration, nad Air-Conditioning Engineers. Retrieved 24 January 2013.
- ASHIRAE Press (2006). The ASHRAE Green Guide. Butterworth-Heinemann. p. 191. ISBN 0080553397.
- "Field Evaluation and Verification of Biological Control in Operating Cooling Tower Water Systems Utilizing Non-Chemical Pulse Electric Field Devices". Cooling Technology Institute. Retrieved 24 January 2013.
- Tomczyk, John (5 September 2011). "The Professor: Chemical-Free Cooling Tower Treatment". ACHR News. Retrieved 24 January 2013.
- Clearwater Systems (1 January 2005). "Chemical-Free Treatment of Recirculating Water Using Pulsed-Power". Environmental Expert. Retrieved 24 January 2013.
- "Dolphin “Pulse Power” Cooling Water Treatment". Cooling Technology Institute. 7 February 2008.
- "Pulsed Power Systems For Food And Wastewater Processing" (PDF). Diversified Technologies. Retrieved 24 January 2013.