Chemical Engineering Department, Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain.
Chemical Engineering Department, Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain.
Waste Manag. 2020 Mar 15;105:566-574. doi: 10.1016/j.wasman.2020.03.004. Epub 2020 Mar 10.
This work evaluates the potential of hydrothermal carbonization (HTC) to valorize the digestate derived from the anaerobic digestion of sewage sludge into useful materials for P and energy recovery. The hydrothermal treatment of digestate at 180-240 °C did not lead to high-rank hydrochars. On the other hand, inorganic P concentration did not change with the temperature, while as the carbonization temperature increased, the organic P retention yield in hydrochar became lower, increasing the total P in the process water obtained at the highest temperature, up to 25.3%. P recovery from acid leaching of the hydrochar obtained at 180 °C, via precipitation with CaO at pH up to 9, led to a brown solid precipitate with total P content close to 42 mg g, in the range of low grade phosphorus ores. Moreover, acid leaching reduced by 50% the ash content, yielding lignite-like upgraded hydrochars with higher heating values in the range of 20.5-23.1 MJ kg, fairly interesting as solid fuels. Anaerobic digestion of the process water enabled additional energy recovery in form of biogas (325 and 279 mL CH g VS -at standard temperature and pressure; STP- from the process water resulting at 180 and 210 °C, respectively).
这项工作评估了水热碳化（HTC）将来自污水污泥厌氧消化的消化物转化为有用材料以回收磷和能源的潜力。在 180-240°C 的水热条件下处理消化物不会导致高品位水热炭。另一方面，无机磷浓度并未随温度而变化，而随着碳化温度的升高，水热炭中有机磷的保留产率降低，导致在最高温度下获得的过程水中总磷增加，最高可达 25.3%。通过用 CaO 在 pH 高达 9 的条件下沉淀，从在 180°C 下获得的水热炭的酸浸中回收磷，得到一种总磷含量接近 42mg/g 的棕色固体沉淀物，处于低品位磷矿石范围内。此外，酸浸将灰分含量降低了 50%，产生了类似于褐煤的升级水热炭，其高位发热量在 20.5-23.1MJ/kg 范围内，作为固体燃料相当有趣。过程水的厌氧消化以沼气（分别为 325 和 279 mL CH g VS -在标准温度和压力下，STP-来自于 180 和 210°C 下的过程水）的形式实现了额外的能量回收。
