UNIVERSITY PARK, Pa. — Able to store carbon to offset emissions and prevent soil degradation and pollution, charcoal-like biochar could offer a sustainable solution to a lot of environmental challenges — if its production can be made greener. Supported by a three-year, $799,883 grant from the U.S. Department of Agriculture (USDA) National Institute of Food and Agriculture, an international team led by researchers at Penn State will address the so-called “dark side” of biochar, assessing the threat of organic contaminant residues in biorefinery char products.

Biochar comprises organic waste material and is made by pyrolysis, a process that involves heating the organic material in a limited oxygen environment. While biochar has significant potential for use as a soil amendment and for carbon sequestration, its manufacturing process can produce harmful compounds if it is not designed and executed properly.

“While the title of our research project — ‘The Dark Side of Biochar: Addressing the Threat of Organic Contaminant Residues in Biorefinery Char Products’ — may sound ominous, our main goal is to help make sure that problems don’t crop up in the making of biochar,” said team leader Daniel Ciolkosz, associate research professor of agricultural and biological engineering in the Penn State College of Agricultural Sciences. “That way, we can help ensure that biochar lives up to its potential as a positive and beneficial bio-based product.” 

The goal of the research is to identify and test design and optimization strategies for biorefineries to produce biochar without the presence of dangerous organic compounds such as such as benzene, hexane and toluene, Ciolkosz explained. As part of their work, the researchers are assessing how these contaminants are created and disposited in biochar, as well as evaluating treatment processes to remove them.

“If process conditions aren’t right and these toxic compounds are produced, workers could be exposed to harmful conditions and the biochar could end up being a source of contamination, reducing its applicability and acceptability for widespread use,” he said. “This project will characterize the emission of harmful organic compounds from biomass during conversion to biochar in a biorefinery, and its redeposition on the biochar.”

In the study, researchers will use biomass feedstocks, such as crop and forestry residues, algae and municipal organic waste, from various sources in experiments designed to assess emissions and contaminant levels resulting from biochar manufacture. They also will evaluate engineered treatment processes for contaminant removal and utilization. Based on their findings, they’ll analyze the overall performance of biorefineries and develop strategies for design and optimization of biorefineries that include biochar in their product mix.

Other members of the research team include Juliana Vasco-Correa, Penn State assistant professor of agricultural and biological engineering; Andrzej Białowiec, Wrocław University of Environmental and Live Sciences, Poland; David DeVallance, Commonwealth University of Pennsylvania; and Thomas Causer, Advanced Torrefaction Systems.