With high energy prices and Russian embargos pushing up fertilizer costs, New Hampshire farmers are returning to a homegrown nutrient source — sludge generated from wastewater treatment plants across the state.
The state’s only sludge hauler-processor has run out of its Class A product, a biosolid that contains fewer pathogens and is less regulated than the Class B product.
With some fertilizer prices doubling compared to last year, farmers have renewed their interest in Class B sludge. Holderness-based Resource Management Inc. (RMI) provides the Class B to farmers and spreads it on fields for free.
“Basically, it’s good fertilizer, especially this year with fertilizer prices so high,” said Adam Crete, whose Highway View Farm is located in Boscawen.
Last year, he avoided sludge entirely. But the higher fertilizer costs have prompted him to accept some sludge this year. Manure from his 200-head dairy operation provides most of the nutrients for his soil, and the farm also is changing crop rotation and tilling practices to improve soil health, he said.
His sludge order arrived April 18.
In making greater use of sludge, farmers are overcoming misgivings of the past few years that focused on per- and polyfluoroalkyl substances (PFAS), so-called “forever chemicals,” according to Anthony Drouin, who supervises the wastewater residuals management program for the state Department of Environmental Services.
Charley Hanson, a co-owner of RMI, said he’s seen some hesitancy about biosolids in the past because of PFAS issues.
“It’s where perception starts taking over from reality,” he said.
Drouin said New Hampshire sludge has been tested for PFAS-related chemicals since 2017, but that is just for data purposes. With no standard in place, the state cannot reject a Sludge Quality Certificate because of PFAS levels.
According to the most recent data, an average of 44,000 tons of biosolids were spread on New Hampshire fields annually from 2016 to 2020.
State officials and environmentalists say land application of biosolids is tightly regulated in New Hampshire.
Wastewater and paper-mill treatment plants must test their sludge annually for 186 potential contaminants — including heavy metals, semi-volatile organic chemicals and nutrients — before the sludge can earn state approvals and RMI can haul it away for use on land.
Every spreading operation is listed in advance in local newspapers. And lengthy reports track everything from the day it is applied, the desired nutrient levels, setbacks from streams and the crop grown.
Farm-field soil sampling takes place before spreading to ensure the correct amount of application.
Drouin said sludge-spreading has taken place for decades and is incorporated into the Clean Water Act, which has its 50th anniversary this year.
“The bottom line is, the science right now dictates the application rules, the setbacks and the time it has to be incorporated into the soil,” said Michele Tremblay, president of the New Hampshire Rivers Council.
If someone wants to challenge sludge-spreading, they’re going to have to use science to do so, Tremblay said.
“This stuff is being produced and it has to go somewhere,” she said.
No standards yet
Recently in Maine, groundwater and well water at some farms exceeded state PFAS standards by factors in the hundreds, according to news reports.
Levels were so high in one area of Somerset County that officials posted warnings about PFAS levels in any venison from deer killed by hunters.
In April, the Maine Legislature passed a bill to ban sludge with any amount of PFAS from use on farm fields.
RMI’s Hanson said the Maine contamination appears to be linked to sludge that came from industrial operations, mostly paper mills, and not typical sewage treatment plants.
While New Hampshire has required tests for PFAS-related chemicals in sludge since 2017, the DES won’t start working on standards until November 2023, which means no sludge can be rejected because of PFAS levels.
Maine has set a standard of 5.2 parts per billion of PFAS in soils. New Hampshire biosolids range from 4 to 6 parts per billion, DES’s Drouin said.
Drouin said New Hampshire wants to be thorough before it sets standards for the chemical. Right now, he is waiting on a U.S. Geological Survey study into soil and sludge-leaching of PFAS, which won’t be completed until the fall. Its findings are needed for the DES to develop a standard, Drouin said.
He said current values used to model PFAS are inaccurate.
“Patience is needed with the scientific method,” he said. “We want to create a defensible number.”
If landspreading is no longer an option for sludge, the alternative is landfilling. Drouin said costs for a wastewater treatment plant to landfill sludge can be twice as high as land application, not including transportation costs.
Hanson said Maine’s problem has been traced to sludge from paper mills. RMI handles sludge from both paper mills and wastewater treatment facilities.
Drouin said the sludge goes through the same sampling and approval process, no matter what the producer. Every paper mill has different processes, and a couple of the New Hampshire paper mills have had non-detectable levels of PFAS in their sludge, he said.
Hanson stresses the ubiquitous nature of the chemical when he speaks to customers.
“It’s all over the place, certainly in biosolids,” Hanson said about PFAS. “We feel we can manage this.”
Several factors have pushed up the cost of fertilizer. Fertilizer production is energy-intensive and is especially reliant on natural gas, Hanson said.
After Russia, one of the world’s largest producers of fertilizers, invaded Ukraine, embargoes followed, pushing prices up further, Hanson said.
The price for urea, which is dependent on natural gas, has more than doubled, to more than $940 a ton, he said.
Meanwhile, his price of Class A biosolids was $5 to $15 a ton before he ran out recently. Class B is free, and his company spreads the product.
“Some people get out, some are coming back in,” Hanson said. “We have a lot of people who want product.”