Pyrolysis of creosote-treated railroad ties to recover creosote and produce biochar
2020
Gonzalez, Javier M. | Boddu, Veera M. | Jackson, Michael A. | Moser, Bryan | Ray, Peter
Annually in the USA, about 800,000 creosote-treated railroad ties (“ties”) may end up in landfills, presenting environmental concerns. Pyrolysis of ties to recover creosote and produce biochar may be an alternative to landfill disposal. In this study, ties were pyrolyzed under different conditions at 667 and 700 °C at two different facilities, and analyzed for residual creosote (as polyaromatic hydrocarbons, PAHs). Condensed gases from the 700 °C pyrolysis were collected. Toxicity and leachability tests were conducted on ties and biochars. Relative to the ties, both 667 and 700 °C pyrolysis reduced the extracted PAHs by 98.71 and 99.94%, respectively. Only the 700 °C pyrolysis biochar qualified as “basic” biochar for soil amendment according to the European Biochar Certificate PAHs requirements. The condensed gases generated a lower (high PAHs content) and upper (low PAHs content) layer. No trace metals of environmental concern were detected on the biochars using toxicity and leachability tests.
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