A good partnership can be hard to find, but Wilmington, Del., knows precisely what it is looking for in a wastewater facility operator.

The city recently hired Jacobs/OMI to operate its wastewater treatment plant, combined sewer overflow facility and renewable biosolids facility.

This has been touted as “one of the country’s largest public-private partnerships for wastewater operations,” according to a press release by Jacobs.

To give an idea of the scope of what Jacobs will work with, Wilmington’s wastewater treatment plant is designed to treat 105 million gallons per day and sees an average flow of 68 mgd. Primary treatment capacity is 250 mgd, secondary peak treatment capacity is 168 mgd and tertiary is 340 mgd.

This is largely because the plant is regional, taking in wastewater from throughout the northern one-third of Delaware, not just from the city of Wilmington.

The city has big goals for its wastewater facilities, and according to department of public works Commissioner Kelly Williams and public works Deputy Commissioner Vincent Carroccia, Jacobs/OMI is just the right firm for the job.

“We are looking forward to partnering with Jacobs to bring us into the next century: a wastewater treatment plant that reflects that we are in 2020,” Williams said. “We hope that we can achieve things like net zero and reducing landfill application.”

Wilmington will combine its CSO program, wastewater treatment plant contract operations, pump stations and renewable energy biosolids all under Jacobs, for a savings of $1 million in the first year of the contract.

“We found that because everything is interconnected, instead of having different people run different parts of the systems, we can have one clear contractor to really integrate the process in the most efficient way possible,” Williams said.

Until the mid-1990s, Wilmington used its own workforce to operate its wastewater facilities. Roughly 22 years ago, the city hired Veolia Water Technologies to take over.

“A contract operator offers access that we feel represents a long-term value for the city,” Carrocia said. “We were able to reduce costs and update facilities.”

However, what worked 22 years ago does not necessarily work now. When it came time to seek a new contract, the city took the time to assess its current needs and expectations.

“We wanted to get our goals straight and prioritize what was important to us,” Williams said.

Five companies responded to Wilmington’s request for proposals. After an extensive review process, the list was reduced to three companies capable of operating and maintaining a wastewater treatment plant the size of Wilmington’s. These remaining contractors were brought in for interviews with the city and a final selection was made.

One contractor ended up dropping out, leaving Jacobs/OMI and Veolia as the top two, with Jacobs coming out on top. 

“The city evaluation team felt that the Jacobs proposal offered the city ratepayers a better long-term value,” Carroccia said.

With Jacobs overseeing wastewater operations, the city has high hopes. Its biggest goal is to achieve net-zero status.

This will not happen right away. To start things off, Jacobs will fund a renewable energy biofuel study by PJM Interconnection. Depending on the results, the facilities could reach net-zero capability by year five of the new contract.

“There’s only one plant in the U.S. that I’m aware of that they’ve been able to get to true net zero, so it’s a fairly lofty goal,” Williams said.

Still, the city, along with Jacobs/OMI, is determined to achieve it.

Harnessing enough clean, renewable energy to go net zero revolves around sludge.

Sludge produces methane gas, which can be converted into a clean biofuel and used to power electricity-generating engines. This could potentially make enough power for Wilmington to sell back to the grid, Williams said.

Sludge is difficult to dispose of and typically ends up in a landfill. Wilmington hopes to incorporate a process that will remove the water from the sludge, making it lighter and easier to dispose of or to use as a Class A biosolid for farmland fertilization.

“The whole purpose with the the facility is to use our processes and the landfill gasses and dry the sludge and provide enough power to run our plant,” she said. “It’s a pretty lofty goal and we’re working toward making it efficient. It’s energy saving, cost saving, much better for the environment.”

Besides going net zero, Jacobs plans to upgrade the existing supervisory control and data acquisition system for the wastewater treatment plant. The SCADA system provides data on everything from flow rates and pump speeds to temperatures and chemical treatment dosing.

Another goal is to improve the combined sewage overflow monitoring system and integrate it into the new SCADA system.

While many cities would also need to factor in anticipated increases in use and capacity, this is not a concern for Wilmington.

“We’re essentially geographically restrained,” Williams said. “There are not a lot of opportunities to add a lot of growth.”

Though the partnership has just begun, Wilmington is already looking ahead. In 20 years, the city will go through the bidding process again and will need to know requirements going forward.

“We’ll ask the company for any value-added types of ideas their engineering staff wants to bring to the table,” Williams said.

Due to the nature of wastewater treatment, environmental regulations are often updated.

“The basics of wastewater treatment, you bring in sewage and dirty water and you clean it and you discharge it, in our case back to the Delaware River,” Williams said. “It’s a highly regulated process, so compliance with the regulations is paramount. All of the sudden, we may have to address some type of nutrient or some pollutant.”

While it is too soon to tell how much the city will save on energy once the wastewater facilities have gone net zero, Wilmington looks forward to what the future will bring.