Biocrude production and nutrients recovery through hydrothermal liquefaction of wastewater irrigated willow

The willow was converted at supercritical water conditions (400 °C) for 15 min in a micro-batch reactor (10 cm3), and high mass yields (39.7%) of energy dense (38.6 MJ kg−1) biocrude oil were obtained. It was found that most inorganics, including phosphorus (76% of total P on a mass basis), are mainly transferred to the solid products. The concentration of the elements in the solids eases their recovery and re-use for soil amendment. A different tendency was observed for potassium and sodium, which were almost exclusively collected in the aqueous phase (above 88% for both K and Na on a mass basis). Significant quantities of nitrogen and sulfur, and some metals, were transferred to the biocrude oil, however its quality resulted overall unaffected.