auger feeder c the auger feeder c then conveys the triturated waste towards the mouth of the sterilization chamber s while moving along the auger feeder c and the connected duct co the waste is sprinkled with steam through the nozzles present on the duct co itself by this process the auger feeder c besides transporting the waste towards the sterilization chamber s causes the waste to mix with the steam and allows the steam to penetrate among all the triturated parts of the waste at the end of the auger feeder c the waste triturated and pretreated with steam is introduced into the sterilization chamber s through the gate valve sv provided on the upper opening of the sterilization chamber s itself as the waste is introduced into the sterilization chamber s the stirrer so present inside the sterilization chamber s distributes said waste homogeneously the gate valve sv is closed as soon as the maximum loading level of the triturated waste is reached and at this point the actual sterilization phase inside the sterilization chamber s is started the microwave generators m are set in operation and high temperature pressurized steam is introduced into the sterilization chamber s during the irradiation of the triturated waste with microwaves and the steam flooding process inside the sterilization chamber s the stirrer so keeps rotating thus mixing the triturated waste in such a way as to obtain the maximum microwave irradiation and steam penetration into the triturated waste the actions of the microwaves and of the steam make it possible to increase the temperature and pressure values inside the sterilization chamber s the action of the stirrer so allows the microwaves and the steam to reach all.