Sludge pyrolysis is a promising method for treating excess sludge as a by-product of municipal sewage plants, allowing for energy self-sufficiency and resource recovery. Before sludge pyrolysis begins, a few conditioning agents are added to the sludge that promote sludge dewatering. Potassium ferrate (K2FeO4) is applied as a conditioning agent with both cracking and flocculation effects, but the effects of K2FeO4 on the release characteristics of nitrogen, sulfur, and chlorine during sludge pyrolysis have not been elucidated. In this study, we analyzed the sludge pyrolysis characteristics and chemical state changes of N, S, and Cl contaminants in the dewatered sludge after K2FeO4 conditioning before and after pyrolysis. Further, the release characteristics of condensable/noncondensable gases during pyrolysis were assessed using thermogravimetric mass spectrometry (TG-MS) and pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) analyses before and after conditioning. We found that potassium pertechnetate reduced the activation energy required for the sludge in the pyrolysis process. Noticeably this process made the sludge more susceptible to thermal decomposition leading to volatile production and also influenced the release of different contaminants generated by the pyrolysis process. Moreover, K2FeO4 promoted the release of C/H/O gases and reduced the release of N/S/Cl pollutant gases from the sludge. Overall, this study provides a theoretical basis for the selection of conditioning agents for the sludge conditioning and dewatering steps during the sludge pyrolysis process.

中文翻译：

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高铁酸钾作为脱水调节剂对污泥热解特性及污水污泥热解过程中氮、硫、氯释放特性的影响

污泥热解是一种很有前途的方法，可将剩余污泥作为城市污水处理厂的副产品进行处理，从而实现能源自给自足和资源回收。在污泥热解开始之前，将一些调节剂添加到污泥中以促进污泥脱水。高铁酸钾(K2FeO4)被用作兼具裂解和絮凝作用的调节剂，但K2FeO4对污泥热解过程中氮、硫、氯释放特性的影响尚未阐明。在这项研究中，我们分析了热解前后经过 K2FeO4 调理的脱水污泥中 N、S 和 Cl 污染物的污泥热解特性和化学状态变化。更远，在调节前后使用热重质谱法 (TG-MS) 和热解-气相色谱/质谱法 (Py-GC/MS) 分析评估热解过程中可冷凝/不可冷凝气体的释放特性。我们发现高锝酸钾降低了污泥在热解过程中所需的活化能。值得注意的是，该过程使污泥更容易热分解，从而导致挥发物的产生，并且还影响了热解过程产生的不同污染物的释放。此外，K2FeO4促进了C/H/O气体的释放，减少了污泥中N/S/Cl污染气体的释放。全面的，