Friday, January 27, 2023

NHC signs off on $857K cost increase to fend off nutrient pollution from landfill

The pools in the landfill are constantly filling with effluent water to be treated and returned to the water supply in an almost pure form. (Carl Blankenship/Port City Daily)

NEW HANOVER COUNTY — The New Hanover County Landfill is getting a major new piece of equipment to the tune of $4.6 million after Monday’s board of commissioners meeting.

The money will cover the construction of a new leachate membrane bioreactor system.

READ MORE: ‘The land is just too precious:’ The landfill will become a massive nature park in 60 years

“We jokingly call it our flux capacitor project because it’s such a mouthful,” Environmental Management Director Joe Suleyman told the board.

He said the term is used for a bacteria-rich membrane to remove organic pollutants from the wastewater produced by the landfill.

The pollutants are a concern because, if released into the environment, they could overload waterways with nutrients. It could result in algae blooms that could kill off other plants and animals.

The landfill produces about 50,000 gallons of wastewater every day. Suleyman said the material itself is a far cry from the waste produced by homes, which is run through a sanitary sewer system and returned to the water supply.

“This is some pretty toxic, nasty material,” he said. “And, as you can imagine, it’s just super concentrated with things like PFAS, PFOAS, GenX, all that wonderful stuff.”

The term wastewater is not always used to describe the substance. It is typically described as “leachate” because of its toxicity as a result of rain and anaerobic digestion sucking pollutants out of landfill waste. In November Suleyman colloquially referred to the material as “trash juice” when speaking to Port City Daily.

Suleyman said the current bioreactor system at the site was a used purchase in 1992 and built on over the years. There are no records from where it was purchased and none of his staff worked for the county at that time to indicate where it came from.

The existing bioreactor is at the end of its service life and has begun springing leaks in the form of small cracks. The system is going offline to prevent more damage. The new installation will begin in about two weeks and take eight months to complete.

In the meantime, Suleyman said the water being discharged by the facility will not be a threat to the environment, but the treatment process will place more strain on the other equipment.

The bioreactor is only one part of the system, including ultrafiltration and reverse osmosis. The entire system filters the material so effectively, it is discharged from the landfill as pure water. Suleyman said the entire leachate treatment process is one of several that protect the environment from the heavy industry and pollutants produced by running a landfill, the others being the collection of landfill gas and preventing groundwater leaching with liner systems.

New Hanover’s landfill is the only site in the state that processes its own leachate on site, rather than paying to haul it to a treatment center. Commissioner Rob Zapple described Suleyman’s management of the site as “cutting edge” in how it protects the land.

Suleyman said the other filters will make up for the lack of bioreactor, but it will put more wear on them in the meantime. He estimated the reverse osmosis facility will lose six months off its three-year filter lifespan, being consumed at almost double the normal rate during the next eight months.

Each reverse osmosis filter tube costs about $700 and with about 60 of them in the system, that equals $42,000 in the filters alone. The new system will require occasional maintenance on its pumps, motors and aerators.

Suleyman said his department knew the system wouldn’t last forever and began setting aside money for it a few years ago. Two firms bid on the project initially and the county put the project out to bid a second time but received the same two offers.

Turner Murphy, the same firm that installed the site’s reverse osmosis system, had the lowest bid at $4.6 million, $857,000 over budget. To make up for the difference, Sileyman requested a budget amendment to move $1.3 million from the department’s lagoon relining project fund to cover both the increase and a contingency fund. 

Suleyman said the department has been dedicating funding over the years to eventually follow through with the lagoon project and it was the only “stash of acorns” available. His report on the issue noted moving the money will not affect landfill operations, and the goal is to include the lagoon project in the next five-year capital improvement plan.

The new bioreactor system is expected to treat leachate coming off the landfill cells for years after it closes around 2050.

Zapple made the motion to award the bid and approve the budget amendment, which passed unanimously.


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