The Environmental Protection Agency's planned phase-out of chromated copper arsenate (CCA) as a wood preservative could have meant that CCA could no longer be used in the construction of cooling towers. As reported at the CTI meeting, because of fast action by several members, and by those of others, CCA may continue to be used as a wood preservative on lumber for cooling towers.
According to the American Wood Preservers Institute (AWPI), Reston, Va., "The EPA-approved labels for CCA wood preservatives have been amended to indicate that, effective December 31, 2003, CCA may be used only to treat wood or forest products that fall under the [American Wood-Preservers' Association] AWPA standards listed on the new label." The new EPA label for CCA relies on the 2001 and 2002 (C30 Only) editions of the American Wood-Preservers' Association Standards to specify the categories of wood products that may be treated as of December 31, 2003. AWPA Standard C30 specifies lumber, timbers and plywood for cooling towers.
In another presentation at the CTI meeting, the benefits and pitfalls of supplemental cooling systems were the focus of a presentation by Billy Childers of Aggreko, Houston. While supplemental cooling can relieve temperature-related bottlenecks, reduce operating costs and increase cooling system redundancy, Childers says careful implementation is necessary to achieve all the potential benefits. Childers outlined how to select and size a supplemental cooling system and stressed the need to perform proper water balancing between the existing tower and any supplemental cells or towers that are brought online to augment the cooling system.
Also presented was "Development of an On-site Hypobromite Generator," written by Timothy Keister, chief chemist and president, ProChemTech International, Brockway, Pa., and Patrick Gill, general manager of ProChemTech's Performance Chemical Div., Brockway, Pa., and presented at the CTI conference by Gill. The presentation described a technology used to control biological growth in cooling waters by electrolytically converting a nonhazardous aqueous salt solution into bromine. Bromine, produced only as needed, is effective for control of biological growth, particularly in high pH cooling waters.
The three-day conference program also included technical committee meetings on engineering standards and maintenance, water treatment and evaporative cooling performance and technology.
The next Cooling Technology Institute Conference will be held February 6-10, 2005, at the Westin River Walk, San Antonio, Texas. For more information, call (281) 583-4087 or visit www.cti.org.