Two Towns, One County: A Regional Approach to Wastewater Capacity
Prepared for the 2013 NC AWWA-WEA Annual Conference by Tony Boahn, PE, Vice President, McKim & Creed, Inc.
The Town of Burgaw, located in Pender County, experienced significant growth from 2003 to 2008, resulting in increased pressure on the town’s 750,000-gpd wastewater treatment plant (WWTP). The facility disposed of effluent via a point discharge to Osgood Canal, which is a direct tributary to Burgaw Creek. Burgaw Creek is listed on the Federal 303d list for biologically impaired waters. In 2008 the town’s average daily flow was approaching 80% of the treatment capacity. The current demands, coupled with significant interest from the development community, served as the impetus to develop a master plan and evaluate options to meet long-term wastewater capacity needs.
Wastewater projections indicated that 1.25 mgd of wastewater capacity would be needed. Given that Burgaw Creek was listed as biologically impaired, additional discharge capacity at this location was deemed not feasible. To meet projected demands, several alternatives were evaluated, including:
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- expanding the treatment facility with a new point discharge to the NE Cape Fear River,
- expanding the treatment facility with land application for effluent disposal, and
- installing pump stations and force main to convey wastewater to the Town of Wallace WWTP in neighboring Duplin County.
It was determined that conveying wastewater to the Wallace WWTP was the most cost-effective alternative to meet long-term needs. Wallace was in the early stages of upgrading an existing treatment plant previously owned and operated by a private industry. Pender County had purchased 2 mgd of the proposed 4.42 mgd Wallace plant capacity, but had no infrastructure in place to utilize this capacity. The Town of Burgaw subsequently negotiated an inter-local agreement with Pender County to construct a collection and conveyance system that would utilize the 2-mgd capacity owned by Pender County. The agreement stipulated 1.25 mgd of capacity for Burgaw and an additional 0.75 mgd for Pender County. The recommended system included approximately 65,000 feet of 20-inch and 24-inch force main, a 1.25- mgd pumping station, and a 2.0-mgd pumping station.
Additionally, the project included a unique adaption of the Burgaw WWTP to provide emergency wastewater storage in case the pump station/force main system was unable to convey incoming wastewater flow to the Wallace WWTP. The plant tankage was modified to include a means of diverting incoming flow to the plant tankage and re-directing flow to the pump station/force main system.
The project, which is completed and operational, eliminated a point discharge to biologically impaired waters and provided a regionalized approach to wastewater capacity in Burgaw and northern Pender County.