Hydrothermal liquefaction (HTL) is a thermochemical process for the conversion of biomass into bio-crude oil. However, treatment of post-HTL aqueous by-products is an emerging issue towards the commercialisation of HTL technology. This study investigates the use of non-catalytic wet oxidation (WO) for the reduction of organic compounds and heat production at different temperatures (200–350 °C), residence times (RT) (2–180 min) and excess oxygen. The aqueous phase from HTL of sewage sludge is investigated, and 97.6% of the chemical oxygen demand (COD) and 96.1% of the total organic carbon (TOC) were removed at the highest temperature and retention time. The minimum energy requirement achieved was 9.6 kWh/kg COD removed at 200 °C for 180 min, and the exothermic reactions of the process can generate 28.3% of the required heat. GC-FID and -MS analysis revealed that the degradation of different groups of organic compounds generates acetic acid as an intermediate by-product of WO, being further oxidised at temperatures higher than 300 °C. NH₄⁺and NH₃ are generated from the decomposition of nitrogenated organic compounds showing the highest concentration of 704.5 mg _NH4+ /L at 350 °C after 180 min.

水热液化 (HTL) 是一种将生物质转化为生物原油的热化学过程。然而，HTL 后水性副产物的处理是 HTL 技术商业化的一个新兴问题。本研究调查了使用非催化湿式氧化 (WO) 在不同温度 (200–350 °C)、停留时间 (RT) (2–180 分钟) 和过量氧气下还原有机化合物和产热。对来自污水污泥 HTL 的水相进行了研究，在最高温度和保留时间下去除了 97.6% 的化学需氧量 (COD) 和 96.1% 的总有机碳 (TOC)。达到的最低能量要求是 9.6 kWh/kg COD 在 200 °C 下去除 180 分钟，该过程的放热反应可以产生所需热量的 28.3%。GC-FID 和 -MS 分析表明，不同组有机化合物的降解产生乙酸作为 WO 的中间副产物，在高于 300 °C 的温度下被进一步氧化。NH₄ ⁺和 NH ₃是由含氮有机化合物分解产生的，在 350 °C 下 180 分钟后显示最高浓度为 704.5 mg _NH4+ /L。