After years of planning, Wilmington’s Southside Wastewater Treatment Plant will undergo full replacement beginning later this year, according to Cape Fear Public Utility Authority (CFPUA) officials, eventually leaving the existing facility off River Road near Independence Boulevard obsolete.

Opened in 1972, the plant receives wastewater from much of the city of Wilmington and southern parts of unincorporated New Hanover County. But aging infrastructure and increased service demand from high-density growth areas along Carolina Beach and River roads, for example, have made replacement necessary.

With an estimated $400 million price tag, it will be the costliest capital project in CFPUA’s history, utility officials say.

“Replacing the Southside Plant is critical to ensuring CFPUA continues to meet our community’s current and future wastewater service demands,” said CFPUA spokesperson Cammie Bellamy.

While the Southside Plant has undergone numerous upgrades and expansions over the past five decades and continues to meet regulatory requirements, “it has reached the end of its useful life, increasing the potential for infrastructure and equipment to fail,” Bellamy said.
 

EXPANDING CAPACITY

The Southside Plant is one of two wastewater plants operated by CFPUA, along with the Northside Wastewater Treatment Plant across from Wilmington International Airport.

Currently, the Southside Plant is rated to treat up to 12 million gallons per day (MGD) of wastewater. Its replacement will expand Southside’s capacity to 16 MGD.

By 2044, the average daily flow at Southside is projected to be nearly 13.6 MGD, according to CFPUA data, with one of the most significant jumps in gallons per day coming between 2029 and 2030, just as the new plant is scheduled to come online.

Bellamy noted that for several years, CFPUA has been diverting some of Southside’s flow to its Northside Wastewater Treatment Plant, which is rated for 16 MGD.

This diversion “has allowed us to decrease demands on the (Southside) plant and extend its useful life while planning was underway for the replacement,” said Bellamy. “Completing this project will allow CFPUA to return that flow from Northside to Southside without exceeding the plant’s capacity.”
 

NEW AND IMPROVED

New and upgraded technologies at the replacement plant include new disk filters, which remove contaminants in the final stages of purification, and the addition of a biological nutrient removal treatment facility, which uses microbes, often known as “bugs,” to break down waste and remove carbon, nitrogen and phosphorus. Primary and secondary clarifiers, an ultraviolet disinfection facility and an odor control facility are among other new infrastructure. A larger administrative building and more warehouse space are also planned, while the existing plant’s biosolids handling facility will continue to serve the replacement plant.

The new Southside Plant will also be built entirely above the 500-year floodplain, decreasing the risk of flooding and related damage during major storms.

“Most of the infrastructure of the new plant will be built farther away from River Road than the current plant and behind CFPUA’s existing biosolids storage building, which will continue to serve the new plant,” said Bellamy. “This means that major plant infrastructure such as clarifiers will be largely out of view from the road.”
 

ADVANCED TREATMENT

“What excites me and our staff most about this project are all the new treatment technologies that will be implemented,” said CFPUA assistant operations director Craig Wilson, adding that some of these technologies are already at work at the Northside Plant. “It’s a win for all residents throughout New Hanover County.”

One of the most important benefits of these advanced treatment methods, said Wilson, is the impact it will have on the discharge of effluent, or treated wastewater, to the Cape Fear River.

“The environment is always a top priority,” he said. “The water discharged from the new plant will actually be cleaner and of higher quality than the river water itself.”

The new plant’s footprint will be about 20 acres on the existing plant’s 36-acre property, said Wilson and, except for a few main structures, is expected to be barely noticeable from the road. “You’ll see a lot of trees,” he said, referring to plans to use both existing and newly planted trees to screen the treatment plant from traffic.

Cutting project costs is also a priority, said Wilson.

Site work on the Southside Plant replacement is expected to take place in the fall of this year.