What is promising is that the knowledge of the agricultural utility of biochar is slowly creeping into major development programs such as those described below. Recognition that residual biochar has a better place as a soil building agent than as a fuel is changing researcher’s approach to the waste management problem.
This bodes well for the future. One can see that this is a welcome solution to the major problem facing industrial scale animal husbandry of the effective disposal of manures. These can no longer be simply spread on the surrounding soil because of damage to the environment. So running the material through a wet thermochemical process with a top temperature of 350C is very appealing now that we know that the solid portion is highly suitable as a soil additive.
We are seeing an industry shift over to a superior and truly unexpected economic model. We can soon expect the resultant biochar, and the reported temperature is producing reduced carbon, if not activated carbon, to be sold at the farm gate.
Once agribusiness itself begins to dispose of its waste streams as a 350 degree carbon product to other operators, the rest of the industry will quickly follow suit. Right now the hardware itself is been figured out.
I may be optimistic, but the acceptance of biochar protocols is inevitable and this work shows us that that is the emerging consensus. That five thousand year field test in Brazil has silenced all the usual naysayers who would surely slow the adoption. Recall that the vanadium battery is how twenty years old and it still attracts naysayers who lack any scientific support for their position.
Terra preta has only in the past year really begun to penetrate public consciousness. Prior to that, we had a few lonely articles by a few academic champions. Now field tests are springing up throughout the globe.
Within perhaps five years, every farmer will be clamoring for the stuff. And yes Virginia, there will be millions of new acres of agricultural land brought on stream because of this.
Fueling the FarmWaste for Energy and Independence
Imagine turning a noxious agricultural waste into a value-added bioenergy product for on-farm heating and power—or even into transportation fuels.
Agricultural engineer Keri Cantrell, environmental engineer Kyoung Ro, and research leader Patrick Hunt work at the ARS Coastal Plains Soil, Water, and Plant Research Center in Florence, South Carolina. They have teamed up to explore how thermochemical conversion technologies could be used to generate bioenergy from manure—a resource that the United States, with its intensive livestock production, has in abundance.
“Our goal is to develop new waste-treatment methods and strategies that small farms and concentrated animal-production facilities could use to meet their energy needs,” Cantrell says.
One approach—wet gasification—converts wet manure slurry into energy-rich gases and relatively clean water. The catalytic version of this technology is under development at the U.S. Department of Energy (DOE) Pacific Northwest National Laboratory. This process is expected to destroy pathogens and has been found to destroy odor-generating volatile organic compounds at the processing conditions of 350˚C.
At this high temperature, wet gasification can destroy pharmaceutically active components like hormones. This process could theoretically convert the manure in as little as 15 minutes, far exceeding the days and months required by existing anaerobic and composting methods.
The Florence researchers developed a cost-benefit model of wet gasification to calculate estimated returns and concluded that liquid swine waste can have a net energy potential comparable to that of brown coal.
In addition, the ARS team is investigating pyrolysis technology, which uses heat and an atmosphere devoid of oxygen to convert the manure into a char, or “green coal.”
“Green coal can serve as an energy source for on-farm use, or it can be transported to coal power plants for feedstock,” Ro says. “It can also be transformed into activated charcoal. This charcoal can be applied to soil to improve soil quality, and it also reduces greenhouse gases by permanently sequestering carbon.”
The group is also working in collaboration with the Advanced Fuels Group at the DOE Brookhaven National Laboratory in New York. They are evaluating different catalysts needed to facilitate conversion of “syngas”—the gas produced when animal wastes and other biomass are gasified—to liquid fuels.
“Computers used to take up the basement of the math building,” Hunt says. “We’d like to be able to shrink down a process to run the farm engine in the same way.” With this kind of system, farmers would be able to produce their own energy sources and eliminate the need to transport manure offsite. The trick is to make the system productive and affordable.
The Florence researchers know that the benefits of any biofuel must be weighed against its economic and environmental production costs. “The truly exciting reality is that numerous needs in energy, nutrient recycling, climate change, and biosecurity will foster synergistic development of technology for future agriculture,” Hunt says. “Our research is only one part of the answer as we look for new energy supplies.”—By Ann Perry, Agricultural Research Service Information Staff.
This research is part of Manure and Byproduct Utilization, an ARS national program (#206) described on the World Wide Web at www.nps.ars.usda.gov.
Keri B. Cantrell, Patrick G. Hunt, and Kyoung S. Ro are with the USDA-ARS Coastal Plains Soil, Water, and Plant Research Center, 2611 W. Lucas St., Florence, SC 29501-1242; phone (843) 669-5203, ext. 113 [Cantrell], ext. 101 [Hunt], ext. 107 [Ro], fax (843) 669-6970.
