CMSD's Wastewater Treatment Plant Upgrades
Creative financing led to top performance while saving costs
The Contentnea Metropolitan Sewerage District operated a mid-1970s plant that served the towns of Winterville, Ayden and Grifton in North Carolina. The age of the system had left it struggling with high inflows, overflows and violations after heavy rains, and the District was placed under a Consent Order that mandated repairs and upgrades. Additionally, the plant's two-stage activated sludge process was running at its redline and enhanced nutrient removal was needed to meet the effluent limitations in the Neuse River Basin.
In developing a creative financing plan that packaged grant and loan funds from the District and its three member towns to pay for the improvements, the funding resources included the NC Rural Center, USDA-Rural Development, Clean Water Management Trust Fund, and Construction Grants & Loans (now NC-DWI). With financing in place, the project was address in two phases:
Phase 1 included a new headworks with mechanical screen and screenings compactor, vortex grit removal and Parshall Flume, lift pump station, deep bed denitrification, UV disinfection, post aeration tank and outfall to Contentnea Creek.
Phase 2 expanded the plant's capacity to 3.5 mgd with five-stage biological nutrient removal, activated sludge process, secondary clarifiers, a RAS/WAS pump station, sludge dewatering with dual screw presses and modifications to the existing basins for flow equalization and additional sludge stabilization/holding facilities.
As a result of the creatively funded solutions, CMSD is the highest performing system among its peers with current average Total Nitrogen concentration of just .98 mg/L and average Total Phosphorous concentration of 0.14 mg/L (through the first quarter of 2016).