Historically, wastewater treatment lagoons have been one of the simplest and least expensive wastewater treatment systems to construct, operate, and maintain. One major drawback of wastewater treatment lagoons, however, is that they may not adequately remove all contaminants—such as BOD, TSS and Ammonia—from wastewater, requiring additional treatment to meet local discharge standards.
For 60 years, the Town of Clarkton relied on a wastewater treatment lagoon that discharged to Browns Marsh Swamp. But when the lagoon was no longer able to adequately treat wastewater under the requirements of its NPDES permit, the state of North Carolina placed the Town under a Special Order by Consent, a designation that indicates a wastewater treatment facility is out of compliance and effectively places a moratorium on all new wastewater hookups. Under the Special Order by Consent, the Town could not permit any new development until the wastewater situation was resolved and faced additional penalties and fines if the compliance schedule was not followed.
WithersRavenel helped the Town address its compliance issues by evaluating three options to upgrade the existing plant; land application, regionalization via pumping to the adjacent Town’s wastewater system or improvements to the existing treatment system. The most cost-effective option was a 240,000 gpd precast concrete WWTP with influent pump station improvements, influent screening, flow equalization, extended aeration, tertiary filtration, sludge holding and UV disinfection. Conjunctive reuse facilities allow the Town to utilize reclaim water for tree farm irrigation and non-potable water uses. To finance the project, WithersRavenel helped the Town obtain approximately $1.7 million in grants and low interest loans from the North Carolina Rural Economic Development Center, Clean Water Management Trust Fund, and North Carolina State Revolving Loan Program. The completed wastewater treatment plant is actually easier to operate than the wastewater treatment lagoon was, and requires the use of fewer chemicals, which is better for the community and the environment in the long run.