A new research paper led by Osama Khoury (PhD student) was recently published in the journal “Waste Management“.
The growth in world population is a driving force behind increasing food demand and consumption. Phosphorus (P) is an essential element for plant growth, metabolism, and reproduction and considered as a critical player in global food security. P scarcity is one of the key challenges of the 21′s century, as the primary global P resource largely originates from a finite quantity of sedimentary phosphate rocks. In addition, population growth contribute to the grand challenge of increasing the sustainability of wastewater treatment plants. Hydrothermal carbonization was studied as a nutrient recovery platform, transforming sludge into a valuable hydrochar. Under all reaction conditions, phosphorus recovery values exceeded 80%, with the dominated fraction of inorganic-P in the hydrochar being HCl-extractable. Although HCl-extractable P is considered a moderately labile P fraction, P phytoavailability assays indicate that sewage sludge hydrochar is an excellent source for P, surpassing soluble P, likely due to its slow-release nature. We postulate that polyphosphates constitute a significant portion of this P pool. Overall, we emphasize the benefits of using HTC as a circular economy approach to convert sludge into a valuable hydrochar.
For full paper click here