Monday, July 15, 2024

Could the Cape Fear use trees to filter water instead of burning them?

This is the second part in a series on development practice in the Cape Fear. Part one addressed the impact burns and land clearing have on human health and wildlife habitat; it can be accessed here.

A recently cleared and burned parcel off Lendire Road. To the right and rear of the frame is more forested area. A large housing development lies to the left. (Carl Blankenship/Port City Daily)

SOUTHEASTERN N.C. — Setting brush piles ablaze to make way for new development causes air quality issues and clear-cutting that precedes it erodes habitat. But finding an efficient alternative is difficult.

READ MORE: Why is Cape Fear on fire?

Though burn piles release toxic smoke and carbon dioxide, a promising option to dispose of the wood en masse, known as “biochar” — which has little environmental impact — carries its own baggage.

Exactly how much wood is being burned in the Cape Fear remains a mystery, since there is no government effort to track how many trees are razed. The smoke contains a mix of formaldehyde and particulates that can cause serious respiratory illness. As reported last week in part one of the series, burning trees also produce 2.5 times more carbon dioxide than natural gas.

Rather than burning, developers may sell timber from trees of large enough size and useful species like pines. Yet, there are no local regulations preventing them from burning.

Trees also can be mulched or turned into compost with gas-powered equipment. The City of Wilmington, for example, mulches any trees its staff removes to use for landscaping. The city does not allow open burns within its limits yet does not restrict how trees are disposed. 

Disposal also varies by counties and municipalities in the tri-county region. In the unincorporated parts of New Hanover, Brunswick and Pender counties, open burns are allowed with a North Carolina Forestry Service permit.

Port City Daily emailed each member of the New Hanover County Board of Commissioners on Jan. 3 and asked if the practice of clear-cutting and burning concerns them. Questions included if they would be interested in receiving information on the issue or considering new regulations. 

None responded.

Elsewhere in the country there are pushes from local governments to use waste wood to produce and use biochar. Biochar is a generic term for black residue produced by heat with “little to no oxygen,” according to the Environmental Protection Agency. The main ingredient is carbon, but the chemical composition can vary wildly based on the material and the method of production.

The U.S. Biochar Initiative simply defines the substance as a “fine-grained charcoal made by pyrolysis.”

The process can be self-sustaining in the absence of oxygen because, once started, the chemical phase changes will produce flammable gas, termed “syngas,” and a liquid component called “bio oil.”

Biochar is used to improve soil, filter waste water, clear contaminants from bodies of water and as an additive to other products like concrete. 

The City of Lincoln, Nebraska, was awarded a $400,000 grant in June to jumpstart its own program to produce the black substance, though prior it trucked in 20 tons from across state lines. The city plans to produce 600 to 700 tons of the material each year.

Minneapolis has been using biochar as a soil additive since 2014 and Cincinnati announced a plan to produce it in December.

Wilmington resident Sharon Valentine first encountered the material in 2008 during a visit to Peru where she witnessed dark soils enhanced by adding charcoal to fields. She began using biochar as a soil additive to filter waste water and retain nutrients and moisture when converting her former 6,000-acre turkey farm in Bladen County to a conservation easement.

“Biochar, put in soil, produced a 20% increase in native North Carolina crops,” Valentine said. “We tested it on soybeans and corn, and for the heck of it, watermelon.”

Valentine described the burning of native pine forests as a waste of resources and pointed to biochar as an alternative. She is one of several environmentalists Port City Daily spoke to who see biochar as a sustainable use of resources.

Yet, not all are on board with its use.

Environmental publication DeSmog published an investigative series into the push for biochar that outlined dubious and extreme claims by some promoters and a lack of standardization of the material. The investigation also said pluralizing the word, “biochars,” would be more accurate (EPA research occasionally refers to the material in the plural as well). Not all biochars are made equally; their structure and chemical content varies depending on the material they are made from and the manufacturing process.

There is no standardization for how biochar is made and there is ongoing research into how it can best be used. There are concerns it can ruin soils if applied too heavily and may not be environmentally friendly, depending on how it is produced.

Roger Shew, a UNCW geology and environmental science professor, noted biochar as an alternative to burning when he spoke to Leland Town Council in December. In a followup conversation with PCD, he said there are some concerns about its creation.

“There are of course issues with this, primarily economics, as you would need to either haul the material to a kiln to convert the raw product to charcoal or you would have to bring the kiln to the site,” Shew said.

Len Bull, Valentine’s husband, is a former North Carolina State University researcher who headed the institution’s animal science program. Among his other faculty members, he created the university’s animal and poultry waste center in 2000.

“One of the things we got interested in at the center is what kind of equipment could be developed on a scale basis that could handle some of the solid components,” he said.

The team created a machine that would heat organic matter, from hog waste to wood chips, and they ended up with biochar. He said the carbon microtubules in the material bind with nutrients and hold them in place — the same process as a charcoal aquarium filter.

“The work that was done with the biochar at the farm Sharon was talking about did exactly that,” Bull said. “And in this day and age, when we’re worried about sequestering carbon and making better use of organic means of producing food, there’s an opportunity here.”

‘A promising agricultural soil amendment’

Biochar’s effectiveness and how it is best used are still the subject of study, but multiple major research universities acknowledge its potential.

Pennsylvania State University found biochar can convert waste into a more valuable product. Some of the benefits the university outlines are compelling for the Cape Fear, including better moisture retention, better water quality, and improved soil fertility in the long run.

N.C. State currently describes biochar as “a promising agricultural soil amendment because it contains carbon in soil and enhances microbiological activity in sandy sub-tropical soils.”

James Gaspard, CEO of the Colorado-based firm Biochar Now, which carries U.S. Department of Agriculture and EPA certifications, described the process his company employs. It takes a small amount of oxygen to get pyrolysis started in vacuum-sealed kilns. The vessels rise in temperature up to 1,200 degrees fahrenheit and the process runs for 10 hours. 

Gaspard said material the company produces is effective for removing PFAS from water. Currently, it is undergoing EPA analysis he expects to be made public.

Biochar Now’s product is a competitor, rather than equivalent, to granulated activated carbon. GAC is the material used in the filters at Cape Fear Public Utility Authority’s Sweeney Treatment Plant. He said his company’s process produces charcoal with a charge like GAC and publishes test results for pollutants it removes. GAC is also made from natural products like wood and coconut shells.

Gaspard’s company does not market its biochar as a filter medium for drinking water. He said there is a regulatory deficit and some material being sold as biochar should “never get anywhere near someone’s food and water.”

He recounted cases of faux biochar being produced by burning random materials and said the carbon credit side of the industry is filled with fraud. Notably, the firm Mantria was shuttered in 2009 after claiming to operate environmental initiatives, including biochar production. It was exposed as a Ponzi scheme.

Yet, one of Biochar Now’s customers is working on certification through the National Sanitation Foundation for a filter to use the material.

But is biochar better than burning trees?

Critics commonly express that biochar production has potential to tax the environment. An agricultural operation exclusively to harvest timber to create biochar comes with the issues of runoff and gas-guzzling equipment. 

Biochar Now targets waste wood rather than cultivated trees. The process itself also buries more carbon in the soil than the process emits. When pressed if transporting wood adds to the carbon footprint of Biochar Now’s own production, Gaspard noted the company produces insured carbon credits as protection against fraud.

There is some promise in reducing secondary emissions from trucks hauling the material,  by moving the kilns close to the source of wood.

To understand whether producing the material at scale would be a viable alternative to land-clearing burns, local governments would need to first examine how much wood is being burned and how farm timber would travel to be turned into charcoal.

But officials do not know how many trees are being cut down or how much vegetation is being burned. There is no requirement from the state to track those metrics. In 2022 there were more than 4,000 open burn permits issued by the North Carolina Forest Service in New Hanover County alone. There is no field in the permit application to describe how much material will be thrown into the fire.

Still, there are measures that can be taken to reduce the number of trees removed without expensive equipment.

Shew said logs can be laid out with other debris piled on top before being lit. The resulting burn would produce more charcoal, with fewer emissions than a “wet” burn pile stacked haphazardly, because of the oxygen-deprived logs underneath. Of course, the easiest method would be to not cut down the trees in the first place.

Shew said biochar should be considered if area officials are more serious about climate and health, but offered a more-simple solution than mitigating how trees are disposed of.

“The easiest is to reduce the amount of wood debris,” Shew said. “Planned communities preserving trees will do this easily.”


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