McGaughy Kyle, Reza M Toufiq
Institute for Sustainable Energy and the Environment , 350 West State Street, Athens, Ohio 45701, United States.
Department of Mechanical Engineering, Ohio University , Athens, Ohio 45701, United States.
J Agric Food Chem. 2018 Feb 28;66(8):1854-1862. doi: 10.1021/acs.jafc.7b05667. Epub 2018 Feb 13.
In this study, septic tank waste (i.e., septage) was hydrothermally carbonized (HTC) in order to recover macro and micronutrients, while tracking the fate of residual heavy metals. Three different HTC temperatures (i.e., 180, 220, and 260 °C) at autogenous pressures and two reaction times (i.e., 30 and 120 min) were applied on both solid and liquid septages. Hydrochar and HTC process liquids were characterized using ICP, CHNS, and UV-vis spectroscopy. Treatment at 260 °C for 120 min maximized ammonia recovery, producing a liquid with 1400 mg/L of ammonia. Overall, about 70% of available nitrogen ended up in the liquid phase as nitrate or ammonia. Solid hydrochars show potential for fertilizer use, with high phosphorus content of 100-130 kg/tonne. It was found that heavy metals mainly remained in the solid phase, although the concentrations of heavy metals are mostly lower than U.S. EPA regulation for biosolids with the exception of selenium.
在本研究中，为了回收大量和微量营养素，同时追踪残留重金属的去向，对化粪池废物（即污水污泥）进行了水热碳化（HTC）处理。在自生压力下，对固体和液体污水污泥分别采用了三种不同的HTC温度（即180、220和260℃）以及两种反应时间（即30和120分钟）。使用电感耦合等离子体发射光谱仪（ICP）、元素分析仪（CHNS）和紫外可见光谱仪对水热炭和HTC工艺液体进行了表征。在260℃下处理120分钟可使氨回收率最大化，产生的液体中氨含量为1400毫克/升。总体而言，约70%的有效氮最终以硝酸盐或氨的形式存在于液相中。固体水热炭显示出作为肥料使用的潜力，其磷含量高达100 - 130千克/吨。研究发现，重金属主要残留在固相中，不过除硒之外，重金属的浓度大多低于美国环境保护局（EPA）对生物固体的规定。
