The Triangle Wastewater Treatment Plant (TWWTP) is located at 5926 Hwy 55 in southern Durham County. The wastewater collection system, comprised of approximately 105.5 miles of sewer lines and 1,742 manholes, serves customers inside and outside the City limits, including the northern part of the Research Triangle Park (RTP) in Durham County.

The TWWTP was established in the 1960’s and has had improvements completed in the 1970’s, 1980’s, and 2000’s. The latest upgrade significantly reduced the discharge of nitrogen and phosphorus into the Cape Fear River basin. The TWWTP utilizes a five stage Biological Nutrient Removal (BNR) system that discharges into Northeast Creek in southern Durham County. The upgraded facility is permitted by the state to discharge 12.0 million gallons per day. In the fiscal year 2006 the plant treated 1,485,550,000 gallons of wastewater, or an average of 4.07 million gallons per day.

TWWTP operations is currently contracted to United Water Hydro Management. Through the contract with Durham County, United Water provides staff, maintenance, and the expertise to maintain continuous service to the County’s customers. United Water operates the treatment plant and collection system within the state approved permit guidelines for the wastewater plant, collection system, and storm water runoff.