Our innovative VaSA technology brings a solution to the bottlenecks of ammonia recovery from wastewater and efficient production of renewable energy. When VaSA is used for treatment of ammonia-rich wastewater, it shifts the paradigm of wastewater treatment from costly ammonia removal to profitable ammonia recovery. In addition to efficient removal of ammonia and production of ammonium sulfate, incorporating VaSA into anaerobic digestion avoids ammonia inhibition to methane-producing microorganisms, thus enabling stable anaerobic digestion at a higher organic loading rate. The vacuum-assisted low-temperature thermal and mild alkali treatment in the VaSA process enhances solids solubilization and biodegradability of digestate, thus further increasing methane production as stripped digestate is returned to the digesters. When employing VaSA to recover ammonia from digester effluent, it additionally improves dewaterability of digester effluent and raises biosolids from Class B to A.