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21 <br /> Orange County Health Department <br /> , col, <br /> Colleen Bridger,MPH,PhD : Prevent •Promote •Protect <br /> Health Director , ;„ Sz Partnering for the Public's Health <br /> r <br /> yr <br /> Memorandum <br /> To: Michael Harvey, Current Planning Supervisor <br /> CC: Dr. Colleen Bridger <br /> From: Tom Konsler,Environmental Health Director <br /> Date: September 6, 2012 <br /> Re: Geothermal Well Permitting <br /> This memo is in response to your questions regarding concerns about geothermal wells. There <br /> are many types of geothermal wells which can be classified as open or as closed-loop exchange. <br /> Construction and permitting of all types of wells are covered under the rules adopted by the <br /> Orange County Board of Health and administered through the Health Department. The vast <br /> majority of other counties regulate only drinking water wells. The state also has an approval <br /> process for geothermal wells,most of which are"deemed permitted"with minimal site review. <br /> By far the most common geothermal wells in this area are closed-loop and direct exchange <br /> systems. While these systems do require the construction of wells,water is not withdrawn from <br /> them. They are constructed to provide bore-holes into which watertight or gastight pipe loops <br /> are inserted for thermal exchange with the deep groundwater. <br /> Your questions were concerning the open exchange wells,commonly referred to as"pump-and- <br /> dump"systems. In these systems water is withdrawn from a conventional deep-bore well, and <br /> piped into the HVAC exchange unit. After the water runs through the unit,the water is either <br /> discharged back into the same well,discharged into a second well that is approved for injection, <br /> or discharged onto the ground,or into a creek or pond. I assume that the concerns were <br /> expressed about this third type of system as all of the other systems described would have no <br /> impact on groundwater reserves. <br /> The open discharge of geothermal water is not regulated by the state as it is not classified as <br /> wastewater. We rarely see permit requests for this type of well anymore. Our records indicate <br /> that the last one we issued a permit for was in 2009. It is my understanding that the open <br /> Environmental Health Services <br /> 131 W.Margaret Lane,Suite 140•Hillsborough,NC 27278 <br /> Phone:(919)245-2360 1 Fax:(919)644-3006 <br /> www.oratigecountync.gov/envhlth <br />