Department of Chemical and Materials Engineering, University of Nevada, Reno, Reno, Nevada, USA.
Environ Technol. 2023 Mar;44(8):1135-1144. doi: 10.1080/09593330.2021.1995785. Epub 2021 Nov 15.
Phosphorus is a crucial resource for the agricultural industry, but its limited supply requires recovery from waste materials before it is lost and leads to eutrophication. Dairy manure is rich with phosphorus, and the growth and consolidation within the dairy industry has led to dairy manure management becoming a significant concern. Hydrothermal carbonization (HTC) and membrane distillation (MD) were investigated as an alternative to treat dairy manure and recover nutrients, specifically phosphorus and nitrogen. HTC is a thermal treatment process that converts organic matter into a hydrochar analogous to a low-grade coal, and MD is a thermally-driven separation process that can utilize low-grade waste heat from HTC, thus the two processes are synergetic. A byproduct of the HTC process is the aqueous product (HAP) that contains the water-soluble nutrients and organic components of dairy manure. In this work, the efficacy of MD to concentrate the nutrients in the presence of dissolved organic carbon was assessed. Samples included synthetic nutrient-rich streams as well as HAP produced at HTC temperatures ranging from 200 °C to 260 °C. In each case, the nutrients were successfully concentrated in the feed loop with rejections >99%. Dissolved carbon was found to foul the MD membrane at levels proportional to its hydrophobicity, with little fouling observed for glucose and substantial fouling observed for HAP solutions created at higher temperatures.
磷是农业产业的重要资源，但由于其供应有限，需要从废物中回收，以防止其流失并导致富营养化。奶牛粪便是富含磷的，而奶牛养殖业的发展和巩固使得奶牛粪肥管理成为一个重要的关注点。水热碳化（HTC）和膜蒸馏（MD）被研究作为处理奶牛粪肥和回收营养物质，特别是磷和氮的替代方法。HTC 是一种热处理过程，可将有机物转化为类似于低质煤的水热碳，而 MD 是一种热驱动的分离过程，可以利用 HTC 的低品位废热，因此这两个过程具有协同作用。HTC 过程的副产品是含有水溶性养分和奶牛粪肥有机成分的水相产物（HAP）。在这项工作中，评估了 MD 在存在溶解有机碳的情况下浓缩养分的效果。样品包括合成的富营养物质流以及在 HTC 温度为 200°C 至 260°C 下产生的 HAP。在每种情况下，营养物质都成功地在进料回路中浓缩，排斥率>99%。发现溶解的碳会按照其疏水性成比例地污染 MD 膜，对于葡萄糖观察到的污染很少，而对于在较高温度下产生的 HAP 溶液观察到的污染则很严重。
