Patent ID: 9073770
Filing Date: 2015-07-07
Classification: C02F,Y02E,Y02W

Abstract:
1. An apparatus for digesting waste, comprising: a digester tank; a vertical pump tube disposed within the digester tank; a propeller disposed within the vertical pump tube and configured to pump a waste material upward through the vertical pump tube from a bottom of the digester tank towards a top of the digester tank, wherein the waste material comprises heavy solids that fall to the bottom of the digester tank and light solids that rise to a waste material top level located near the top of the digester tank; a controller configured to operate the propeller to maintain at least a portion of the heavy solids in suspension within the waste material in the digester tank during at least part of a recycle operation; a drainage trough configured to collect the light solids that rise to the waste material top level; an auger, wherein the auger is located inside the drainage trough and is configured to pull the light solids collected by the drainage trough toward a discharge tube of the digester tank; a skimmer; and a heavy solids outlet tube located at the bottom of the digester tank through which the heavy solids are purged from the digester tank, wherein the skimmer pushes the light solids over the edge of the drainage trough and into the drainage trough, and wherein a top portion of the vertical pump tube is disposed far enough below the waste material top level such that the heavy solids fall to the bottom of the digester tank after being propelled up the vertical pump tube rather than being propelled to at or above the waste material top level and discharged through the drainage trough and discharge tube.