Crow Wing County is the first in the state to convert landfill leachate on site into “near drinking water” quality with an environmentally friendly method that is generating nationwide interest.
In April, the county entered into an agreement with HTX Solutions, a Houston, Texas-based company, to treat the county landfill leachate, which is water that drains or leaches from a landfill.
“There is a lot of cost, and there’s also a huge risk as well, by transporting the leachate from the site to another location,” said Scott Kobs, field service supervisor/lead operator/automation engineer.
Kobs of HTX Solutions was the guest speaker at The Center’s Morning Club at the senior activities facility in Brainerd and gave an overview of operations Wednesday, Sept. 18.
“We could truck it to the Twin Cities -- imagine how expensive it is to haul water -- about 8 million gallons a year of leachate,” said Crow Wing County Administrator Tim Houle, who along with Commissioner Steve Barrows, was among the more than a dozen of the attendees.
The main disposal method for leachate generated at the landfill involves pond treatment with on-site land application. Leachate must be treated to strict standards set by the Minnesota Pollution Control Agency permit before it is land-applied.
“The reason we can’t keep doing the current method is because of changing drinking water standards, and we do not believe we will be able to strip out all of the things the MPCA is saying we need to strip out,” Houle said. “Therefore, we have to look for a different treatment solution.”
The landfill’s current pond treatment system is insufficient for treating salts, chlorides, boron and certain other chemicals, according to Simonson, but HTX Solutions specializes in water treatment technologies.
“We’re removing any heavy metals. We’re also taking out any other impurities or suspended particulates,” Kobs said. “And normally it costs 13 up to 18 cents (a gallon) to ship this water to be treated. We’re doing it way less than that.”
HTX Solutions also treats landfill leachate for re-use, reclamation and/or safe environmental release by removing, for example, ammonia, macro inorganic compounds, xenobiotic organic compounds, pesticides, coliforms, viruses, and suspended and dissolved solids.
“I think there’s a common idea of the landfill is a dump, that it’s a hole in the ground, and we throw trash in it,” Houle said of the misconception or oversimplification.
HTX wants to treat leachate on a larger scale this summer as part of a demonstration research project with the MPCA. An application for this demonstration research project was submitted by the county to the agency for approval.
“We throw the trash in, it rains, the rain comes through the leachate, we have collection pipes in the garbage that collects the leachate. I believe the first time we collect it, we throw it back on top of the landfill, and it comes back through again,” Houle said.
“And in taking that leachate back through the landfill, it compacts it, which gives us more space, space is money in the landfill business.”
In 2017, the county landfill received 50,000 tons of municipal solid waste and produced between 8 and 11 million gallons per year of leachate wastewater.
“Essentially, the landfill, if you think about it like a big bathtub, we have liners underneath it that catch all of the rain that goes through, and the water that comes through -- because it’s picking up contaminants -- we call that ‘leachate,’” Holmes said.
HTX Solutions began a pilot project at the county landfill in the summer of 2017 to treat the raw leachate.
“What these guys are here to do is to try to convert leachate into something that would approximate drinking water quality,” Houle said at Wednesday’s presentation.
“We’re very interested in this pilot as a cost-effective, environmentally responsible way to deal with the leachate that comes off of our own waste. … Part of the reason I think that we’re here is because we are considering this as a long-term solution for treatment of leachate.”
The results of the county landfill pilot program included reduction of the amount of ammonia in the leachate from 1,200 parts per million to less than 10 parts per million and removal of boron from 16 ppm to undetectable levels, according to officials with HTX Solutions.
“Crow Wing County waste, land management -- they’re one of the few -- and I stress this -- few landfills … where it decreases in size 6 to 8 feet every year,” Kobs saId.
“Normally, other landfills are like 1 or 2 feet, so they actually have interest around the country with people coming in and saying, ‘Wow! What are you guys doing?’”
The five-year agreement proposed at the April board meeting with HTX Solutions was contingent upon county attorney review of the agreement and approval, land services staff review and MPCA approval of the demonstration research project application.
“And this is a five-year contract with negotiations every year. Year one, our planned costs -- assuming we treat 4 million gallons -- is about $236,000 and then we’re looking to treat more in future years,” County environmental services supervisor Ryan Simonson said in April.