Sewage disposal system with aeration and recirculation

Claim 1

IN A TREATMENT METHOD FOR PURIFYING SEWAGE, INDUSTRIAL WASTES AND SIMILAR LIQUIDS, THE STEPS OF SUPPLYING THE LIQUID TO BE TREATED TO A TRICKLING FILTER FOR TREAMENT BY THE FILTER THROUGH BIOLOGICAL ORGANISMS IN THE PRESENCE OF OXYGEN, CONDUCTING THE EFFUENT FROM SAID TRICKLING FILTER TO A SEDIMENTATION AND CLARIFICATION TANK OF THE TYPE HAVING AN ANNULAR DOWNFLOW SETTLING CHAMBER AND A CONTIGUOUS, CENTRALLY LOCATED UPFLOW CLARIFYING CHAMBER WITH AN OVERFLOW FOR CLARIFIED LIQUID, DISCHARGING THE FILTER EFFUENT TANGENTIALLY IN THE ANNULAR SETTLING CHAMBER OF SAID TANK TO EFFECT A CIRCUMFERENTIAL FLOW THEREIN TOGETHER WITH FLOW IN A DOWNWARD DIRECTION TOWARD THE ENTRANCE TO THE CLARIFYING CHAMBER, WHEREBY TO FACILITATE THE DEPOSITING OF THE SETTLEABLE SOLIDS AND CLARIFICATION OF THE LIQUID, DRAWING OFF SOME OF THE LIQUID FROM THE ANNULAR SETTLING CHAMBER, AND SUBJECTING THE DRAWN OFF LIQUID TO ANOTHER FILTER TREATMENT BY RETURNING THE SAME TO THE SYSTEM IN ADVANCE OF THE FILTER TO AUGMENT THE LIQUID BEING INITIALLY DELIVERED TO THE FILTER.