Abstract: An apparatus and method for the treatment of waste solids that allows for the direct transfer of heat between hot waste solids and cold waste solids in a tube-in-tube heat exchanger. Cold solid waste is moved from a cold solid waste source through one tube of the heat exchanger, and hot solid waste is move from a hot solid waste source through the other tube of the tube-in-tube heat exchanger, and heat is transferred from the hot solid waste to the cold solid waste. The waste treatment, including the heat exchange, can occur in a batch mode or in a continuous mode.

Abstract: The present invention includes a method, an apparatus, and a system for the treatment of waste. The method includes the steps of providing a cold waste solids tank that has a cold solids batch therein. The cold solids batch is transferred, after being warmed, from the cold waste solids tank to a thermal conditioning tank for thermal conditioning. A hot waste solids tank remote from the cold waste solids tank is also provided. The cold waste solids tank is filled with a new cold solids batch. The new cold solids batch is pumped from the cold waste solids tank through a heat exchanger, the partially cooled hot waste solids batch is simultaneously pumped from the hot waste solids tank through the heat exchanger. Heat is transferred from the partially cooled hot waste solids batch to the new cold solids batch in the heat exchanger to obtain a pre-warmed solids batch and to obtain a cooled solids batch. The cooled solids batch is discharged from the hot waste solids tank.