Visit to reCap Biochar Processing Site

On Wednesday, February 26, a large group of VegHeadz gardeners visited the reCap biochar processing facility at the Leon County solid waste site. Josh Venable, CEO of reCap, and Keelan Bush Rester, the site manager for the plant, explained the process and answered all questions posed.  Everyone on the tour found it very interesting and impressive.

Woody feedstock for biochar

Josh Venable

Biochar can be created from many different organic materials.  Leon County is the first governmental entity in the United States and pretty much in the world to create biochar from landscape and roadside woody waste. The county pays reCap a tipping fee to process and dispose of the material. It is delivered to the processing site and then cleared of any extraneous undesirable material such as plastic, metal, etc.  The wood feedstock is fed through a grinder which leaves it in very small particles and shreds. 

It is then augered into a large furnace-type drum reactor, where it is heated at very high temperatures 500-600 degrees in this case, in anaerobic conditions in a process called pyrolysis which removes a lot of the material but combustion does not occur. It is then transferred to a final oxidizing chamber called a thermal oxidizer or afterburner, where it is exposed to oxygen and temperatures are raised as high as 2000° to ensure that any remaining air pollutants are destroyed before steam from the process goes out the stack.  The resulting material, which is mostly carbon, is then cooled and fed into large bags, approximately one cubic yard per bag weighing 400-600 pounds.   It is stored on site until delivery to end users. 

Feedstock is fed into grinder

Wood shreds after grinding and
headed for the drum reactor.

Biochar is useful, not only in agriculture and gardening settings, but is being researched for use in road paving, pollution remediation, and many other environmentally positive applications.

The gases produced in pyrolysis are captured on site and recycled as fuel for subsequent processing runs.  The plant is currently processing about 1000 pounds of wood waste an hour which produces approximately 200 pounds of biochar or 20% of the feedstock weight. The site presently employs four workers and is in the process of doubling its processing capacity. It currently processes a small percentage of the total wood waste that is delivered to the solid waste facility, but it is hoped that a much larger portion of the county’s wood waste will be processed as facilities are added, and markets are developed.

Processing of wood waste in this way reduces the area needed to store and decompose solid waste, reduces the emission of gases produced in the decomposition process, and provides an environmentally positive way to dispose of woody material. It’s interesting to note that wood wastes generated and collected from storms and hurricanes are not processed in this way because it is handled under a different contract with FEMA

Germination testing
of many different
varieties

The VegHeadz will be receiving some of the biochar currently being processed, which has smaller particles than that we have on hand and is more desirable for use as a vegetable garden amendment. The planned trial in the garden will be carried out during the fall 2025 season, and beyond if necessary. Germination testing is currently underway by Master Gardeners Dave Skinner, which appears to be quite positive with no negative impact so far from the addition of biochar to the potting soil.

The biochar produced in Leon County is an organic soil amendment, OMRI and Fresh From Florida certified. The process produces not just carbon credits, but carbon offsets. 

Carbon offsets serve as “compensation” to an organization or an individual that invests in a project or solution that will reduce future emissions or sequester existing CO2 from the atmosphere.  Once created, however, carbon offsets are also an asset class that trades freely on voluntary carbon markets. Carbon credits limit emissions, while carbon offsets reduce or remove them.

The drum reactor where the feedstock is roasted at
very high temperatures to leave the carbon residue known as biochar

We will continue to keep you updated as we learn more about biochar and its use in vegetable gardens. Find out much of what we have already learned about its benefits to garden soil and plants under Garden Resources in the left sidebar.  Thanks to the gardeners who made notes and took pictures during the site visit. 

Finished Biochar

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