Energy and nutrient recovery from sewage sludge and manure via anaerobic digestion with hydrothermal pretreatment

Global expectation for sustainability has prompted the transition of practices in wastewater treatment plants toward not only waste management, but also the energy and nutrient recovery. It has been shown that low temperature hydrotherm (HT) treatments can enhance downstream biogas production via anaerobic digestion (AD). Yet, because the application of combined HT and AD is still at its early stage, systematic understanding on the dynamic speciation evolution of critical elements is still lacking. This study investigated the energy and nutrient recovery from sewage sludge and swine manure via combined HT-AD treatment. Bench-scale investigation was conducted for evaluating biogas production and understanding the dynamic evolution of organics and P speciation. C and P speciation were characterized using complementary chemical and spectroscopic techniques, including 13C nuclear magnetic resonance (NMR) spectroscopy, P X-ray absorption near edge structure (XANES) spectroscopy, and sequential chemical extract...