Abstract 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.

中文翻译：

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热解木酚油处理的铁路枕木以回收木酚油并生产生物炭

摘要 在美国，每年大约有 800,000 根经过杂酚油处理的铁路枕木（“枕木”）最终可能会被填埋，从而带来环境问题。热解纽扣以回收杂酚油并生产生物炭可能是垃圾填埋场处理的替代方法。在这项研究中，我们在两个不同的设施中在 667 和 700 °C 的不同条件下对纽带进行了热解，并分析了残留的杂酚油（如多环芳烃、多环芳烃）。收集来自 700 °C 热解的冷凝气体。对连接物和生物炭进行了毒性和浸出性测试。相对于关系，667 和 700 °C 热解分别使提取的多环芳烃减少了 98.71% 和 99.94%。根据欧洲生物炭证书 PAH 要求，只有 700 °C 热解生物炭符合土壤改良剂的“基本”生物炭要求。冷凝后的气体产生了下层（多环芳烃含量高）和上层（多环芳烃含量低）。使用毒性和浸出性测试在生物炭上没有检测到环境问题的痕量金属。