One of the largest construction projects in the history of the City of Wilmington and New Hanover County (prior to consolidation of the utilities under the Cape Fear Public Utility Authority), the Northside Wastewater Treatment Plant Expansion project doubled the previous wastewater treatment capacity, replaced chlorination with ultraviolet disinfection, and was completed for $6 million under the original budget. The team of McKim & Creed/Hazen and Sawyer designed the improvements needed to expand the Northside Wastewater Treatment Plant from 8 to 16 MGD.
Process modifications included new headworks with the capability to remove grit smaller than 125 microns, new primary clarifiers, new aeration to allow for complete nitrification, new final clarifiers and RAS/WAS pumping, new blowers and blower building, new deep bed filters, new UV disinfection system, new effluent pumping station, additional anaerobic digesters, and an option design consideration for a new thermal dryer to produce Class A sludge. The project also involved recovering existing sewer easements, power line easements, and an abandoned railroad right-of-way to construct a new 30-inch force main. The new force main was approximately three miles long and started in an urban area; and crossed wetlands, heavy vegetation, and two large streams along a residential corridor to the downtown Wilmington district where it ended. McKim & Creed provided new easements, CAMA crossings, and topographic survey data.
For this second phase of a two-part improvements project for the Northside Wastewater Treatment Plant to expand it from 8 to 16 mgd, McKim & Creed performed PLC panel design and fabrication services for 11 control panels, PLC and HMI programming and radio. We also provided checkout/startup, and as-built documentation and training as related to the extended aeration, sludge digestion, chemical feed, disinfection, and reclaim high-service processes.