Disclosed herein are systems and processes for treating a Waste Stream comprising biosolids, the Waste Stream provided at varying flow rates and solids concentrations so as to achieve an SOUR of 1.5 mg O2/g/hr or less and an ORP of at least +300 mV. The system includes a biosolids manipulation device to adjust the volume of suspended solids as a percent of the total volume of the Waste Stream to five (5) percent or less; a chemical oxidant feed device to dose the Waste Stream with an oxidant such as chlorine dioxide, ozone, or similar oxidant, and a treatment vessel associated with said chemical oxidant feed device through which said Waste Stream flows, wherein said chemical oxidant feed device and said treatment device are configured so as to achieve a dose rate between 25 and 200 parts per million of the Waste Stream and substantially complete mixing of the oxidant within 30 seconds of dose delivery in the treatment vessel.