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In order to reduce the concentration of contaminants in HVAC cooling towers, a substantial amount of water must be periodically discharged. However, this discharged water, or blowdown, contains anti-scalant, anti-corrodant and an-ti-microbiological toxic chemicals used to control scaling, fouling and corrosion. The blowdown is discharged into local sewage or stormwater systems and ultimately into the environment. Some municipal sewer agencies charge a fee to accept the discharged water from buildings because it contains hazardous materials that must be treated.

Key Facts

  • While high-efficiency crossflow fine-filtration (CFF) is a uniquely effective solution for reducing fouling, only about 15% of all the US commercial buildings use CFF systems in their cooling towers.
  • Unlike total dissolved solids, total suspended solids (TSS) can be reduced by filtration. Reducing TSS makes chlorine and other disinfectants more effective, allowing chemical treatments to be reduced by as much as 50%.
  • In the United States, Legionnaires’ disease is fairly common and serious—one of the top three causes of non- epidemic, community-acquired pneumonia. It is estimated that over 25,000 cases of the illness occur each year, causing more than 4,000 deaths. Only preventive measures, such as more effective water filtration, can end the Legionella outbreaks.