Ohio EPA Proposes More Stringent Non-Contact Cooling Water Discharge Permit for Industry

February 12, 2010

The use of private well water, public water supplies, or nearby surface waters for cooling purposes is a common practice in the industry. Steel mills, metal heat treating shops, food processers, chemical manufacturers, and foundries are among the largest users of such waters for "non-contact" cooling purposes, i.e., the cooling water does not come into contact with the materials being processed. The acronym "NCCW," which stands for "non-contact cooling water," is the term employed to denote this common practice. 

For most of the industry in Ohio, a general permit is issued authorizing the discharge of NCCW to a receiving stream. The permit typically regulates the temperature and pH of the water to avoid potential adverse impacts on aquatic life. If the source water is a chlorinated public water supply, the permit also sets a maximum allowable concentration for residual chlorine in the discharge. 

On February 4, 2010, Ohio EPA issued public notice that it intends to modify the terms of Ohio's existing general permit for NCCW in order to narrow the eligibility criteria, add new monitoring requirements for total residual oxidants and total residual chlorine, and lay the foundation for stringent individual chlorine residual limits. 

With respect to eligibility, the proposed new permit would require that total flow from all NCCW outfalls at a facility, not just the flow from each individual NCCW outfall, be counted when determining whether the required 20:1 ratio between stream flow and NCCW flow is met in order to be eligible for coverage under the permit. This may adversely impact the eligibility of large facilities that have multiple NCCW outfalls, particularly if the receiving stream is small. 

If a facility's source water for cooling is a chlorinated public water supply, the proposed new permit would require regular monitoring for chlorine residual. Depending on the type and amount of chlorine used for disinfection in the public water supply, a stringent numeric chlorine limit will be added that will likely require the facility to install a dechlorination system. These new requirements are particularly problematic if a facility's incoming water has historically high chlorine, a somewhat ironic situation, since most public water suppliers chlorinate for disinfection, and must maintain a minimum chlorine residual in the water at all points in the distribution lines. 

Finally, if the facility adds certain chemicals to its NCCW to control rust and scaling, the permit would require regular monitoring of the discharge for total residual oxidants. Since the Agency's approval is required in the first instance to add these chemicals, as well as their quantities, this new requirement seems to be an unnecessary expense that should instead be addressed during the approval process for the chemical additives. 

Ohio EPA is accepting comments on the proposed new permit through March 25, 2010. Stephen N. Haughey and other members of Frost Brown Todd's Environmental Practice Group can help you evaluate the impact of the proposed new permit on your facility's operations. If you would like a pdf copy of the Ohio EPA's proposed new permit, fact sheet, and public notice emailed to you, please contact Stephen N. Haughey or any other member of the Environmental Practice Group.