State Institute of Agricultural Engineering and Bioenergy, University of Hohenheim, 70599 Stuttgart, Germany.
Molecules. 2022 Aug 19;27(16):5289. doi: 10.3390/molecules27165289.
Nutrients can be recovered from the digestate of an agricultural biogas plant in the form of solid fraction and serve as crop fertilizers. Removal of suspended solids with screw press separators is the most commonly used technique for treating digestate from biogas plants. To increase separation efficiency and nutrient transfer to the solid phase during separation, eight biocoal-based additives were investigated, which were based on beech wood and produced by pyrolysis at temperatures of 350 °C and 600 °C. Four of the biocoals were impregnated with CaCl or MgCl before pyrolysis. The reaction time between the additives and the digestate varied from 5 min to 2 weeks. The application of MgCl-impregnated biocoal synthesized at 600 °C for 20 h increased the nutrient removal efficiency by 76.33% for ammonium and 47.15% for phosphorus, compared to the control (the untreated digestate).
养分可以以固体部分的形式从农业沼气厂的消化物中回收，并用作农作物肥料。用螺旋压榨机分离机去除悬浮物是处理沼气厂消化物最常用的技术。为了提高分离效率和养分在分离过程中向固相的转移，研究了 8 种基于生物炭的添加剂，这些添加剂基于山毛榉木，通过在 350°C 和 600°C 的温度下进行热解生产。其中 4 种生物炭在热解前用 CaCl 或 MgCl 浸渍。添加剂与消化物之间的反应时间从 5 分钟到 2 周不等。与对照（未经处理的消化物）相比，应用在 600°C 下合成 20 小时的 MgCl 浸渍生物炭可将铵的去除效率提高 76.33%，磷的去除效率提高 47.15%。
