Would use logging waste to produce soil enhancer
A local nonprofit is seeking a one-year permit for a pilot project using high-temperature combustion of logging slash and organic waste to produce biochar, a soil amendment that helps retain moisture.
The primary goals of the project are to determine the optimal processing time and temperature for different types of trees — mainly Ponderosa pine and Douglas fir, Tom McCoy, executive director C6 Forest to Farm, said this week. The project would also study the effects of adding different amounts of biochar per acre of soil, he said. C6, a tax-exempt nonprofit, has applied to Okanogan County for a one-year temporary-use permit for the project.
If the permit is approved, logging slash from a state forest restoration project at Virginia Ridge and from Okanogan County’s stockpile of woody waste material would be pyrolyzed at the county’s 22-acre gravel pit on the Twisp-Winthrop Eastside Road. There is no more gravel mining at the site.
Pyrolysis heats biomass beyond typical combustion temperatures in a nearly oxygen-free environment, which prevents the material from burning, according to the C6 Forest to Farm website. When added to soil, biochar can act like a sponge, retaining water and nutrients and increasing productivity, the organization said.
The slash piles are scheduled to be burned this winter. C6 hopes to use this alternative treatment to test their concept and keep smoke out of the air, according to the environmental checklist submitted to the county with the application.
C6’s goal is to produce 40 tons of biochar, which would use about 120 tons of fuel (30 truckloads of green fuel chips), according to the checklist. The organization could produce even more biochar if it receives additional funding, according to the application.
The chipped material would be transported to the gravel pit in trucks — a maximum of 30 trailer loads at three truckloads per day. The resulting biochar would be transported in smaller trucks.
The biochar will be used in agricultural fields and gardens. Some biochar will be part of a research project at Washington State University, McCoy said.
Project details
For the pilot project, C6 plans to lease a pyrolizer that fits on at 5-by-12-foot utility trailer. The unit processes about 1.5 cubic yards of organic matter per batch, which takes about eight hours. Processing time would be from 5 a.m. to 9 p.m.
Electricity to heat the pyrolizer and turn a drum will come from a propane generator. The pyrolizer’s electric motor makes very little noise and won’t be audible away from the gravel-pit property.
The woody material will be chipped before the pyrolysis, either at the timber-sale landings or the gravel pit. Chipping will be the noisiest part of the project and will occur during normal work hours for a maximum of five days.
C6 anticipates starting the pilot project between December and February, depending on funding and permitting. The organization currently has enough money for about six months of operation, McCoy said.
C6 estimates that transportation, set-up and training will cost $7,500. Leasing, acquiring the woody material, and operating the equipment for a year will cost $80,000, according to the C6 website.
C6’s ultimate goal is to reduce the risk of extreme wildfire by supporting forest health treatments and removing small trees that aren’t commercially viable as timber. These forest materials would instead become biochar.
The public can comment on the temporary-use permit application through Dec. 23. To comment or for more information, contact Rocky Robbins in the Okanogan County Planning Department at (509) 422-7117 or rrobbins@co.okanogan.wa.us.
More information about C6 Forest to Farm is at https://www.c6f2f.org.
