Safe disposal of the sludge generated from sewage treatment plant is a major challenge worldwide. Hydrothermal carbonization (HTC) is considered a potential pretreatment alternative for sewage sludge to facilitate the improved resource recovery. In the present study, the mixed centrifuged sewage sludge (CSS) was subjected to the HTC pretreatment to determine characteristics of the solid hydrochar (HC) and liquid fraction (LF) with a purpose of energy recovery and extraction of value-added compounds, respectively. HTC was performed in a high pressure batch reactor at 200 °C temperature for 1–8 h duration. The HC produced after HTC resembled with the low quality peat coal whereas the LF contained value-added chemicals such as humic acid (HA) and phosphate phosphorous (PO₄^3—P). Using ammonium sulphate as ‘salting out’ agent, ~70% of the total HA (~15–16 g/L) could be recovered from the LF. Using the recovered HA, an improvement in the root and shoot lengths of the seeds could be observed. In the subsequent step, the total PO₄³⁻-P recovery of ~80% was obtained as struvite from the residual wastewater.

安全处置从污水处理厂产生的污泥是世界范围内的主要挑战。水热碳化（HTC）被认为是污水污泥的潜在预处理替代品，以促进改善的资源回收率。在本研究中，对混合的离心污水污泥（CSS）进行了HTC预处理，以确定分别用于能量回收和提取增值化合物的目的的固体碳氢化合物（HC）和液体馏分（LF）的特性。 。HTC在高压间歇反应器中于200°C的温度下进行1-8小时。HTC后产生的HC与劣质泥煤相似，而LF包含增值化学品，如腐殖酸（HA）和磷磷酸盐（PO ₄ ^3-P）。使用硫酸铵作为“盐析”剂，可以从LF中回收总HA的约70％（约15–16 g / L）。使用回收的HA，可以观察到种子的根和茎长的改善。在后续步骤中，从残留废水中以鸟粪石的形式回收了约80％的PO ₄ ^3- -P。