Eno River Sewer Pipe Replacement Project
Over the past several months, the City has evaluated numerous choices of materials, locations of proposed pipeline, methods of construction, and provided notification to select property owners, all in conjunction with its consultant, McKim & Creed Inc. The final design plans have been submitted to several review agencies, which have responded with approvals and necessary permits. On March 26, the City formally advertised for bids for construction of the new pipeline and lift station upgrades. Over the next few months, the City will meet with potential bidders for site visits, will receive and analyze bids, provide recommendation of award to City Council, and begin process of formal award and contract execution. Actual construction may start in mid- to late summer, and is expected to take approximately two years to complete.
- The City of Durham Department of Water Management provides sanitary sewer service to the Eno River sewer basin in Durham County, as well as limited portions of Orange County.
- The sewershed drains to an outfall which follows a portion of the Eno River and its tributary streams (see Project Aerial Map).
- The outfall is nearing the end of its service life, and requires replacement to address wet weather and future flows, while minimizing the potential for sanitary sewer overflows (SSOs).
- Upgrades to the Eno River Lift Station are also needed.
- Nearly four miles (20,400 feet) of outfall length will be studied.
- Old outfall pipes will be replaced with newer, larger pipes:
- Existing 24" pipe will be replaced with 48" pipe.
- New pipe diameters range from 15 inches to 48 inches, and increase the capacity of existing 15" to 24" pipes.
- The Eno River Lift Station currently features four pumps:
- Two pumps are rated at 4,200 gallons per minute (GPM).
- Two pumps are rated at 11,000 GPM.
- Upgrades and improvements are needed to handle a peak hourly flow of approximately 40 million gallons per day (MGD)! These upgrades may include additional pumps, new bar screens, and enhanced electrical and ventilation systems.
Please refer to the glossary below for explanations of terms commonly associated with this project.
- Outfall: A large pipe that collects wastewater flow from other smaller wastewater pipelines and transports it further downstream.
- Lift Station: A facility that pumps wastewater from the lower end of an outfall to the wastewater treatment facility or a downstream collection system.
- Sewer basin: A geographical area defined by topography and sanitary sewer infrastructure emptying into a common outlet.
- Peak hourly flow: The highest flow in a one-hour period within a 24-hour period.
- Sanitary sewer overflow (SSO): A situation in which wastewater is discharged into the environment before it reaches the wastewater treatment facility. The discharge usually occurs from manholes, plumbing fixtures or service cleanouts. Most SSOs are caused by grease and debris (rags, sticks, rocks, personal hygiene products, etc.) being flushed into the sewer system via private sewer services. Only water, human waste, and toilet paper are permitted to be discharged into the sewer system.
- Sanitary sewer system: An underground system of pipes that commonly uses gravity to transport wastewater from homes and businesses to a treatment facility, where the water is treated and released into natural water bodies like lakes and streams.
- Sewer manhole: A structure through which a person can gain access to the underground wastewater collection system. In paved areas, manholes are flush with the pavement. In unpaved areas, they are often raised several feet above the ground and are sometimes higher due to flood plain conditions.
- Wet-weather flow: Any
storm-generated flow, mostly in the form of heavy rains or melting snow and ice,
that enters the wastewater collection system.