Method and apparatus for activated sludge treatment

Claim 1

IN AN ACTIVATED SLUDGE TREATMENT TANK OF THE THROUGHFLOW TPE, THE ARRANGEMENT WHICH COMPRISES, A PLURALITY OF TRANSVERSE MAIN PARTITION WALLS DEFINING A HORIZONTAL SEQUENCE OF HYDRAULICALLY INTER-COMMUNICATING TREATMENT ZONES, SAID WALLS BEING ARRANGED TO PROVIDE FLOW PASSAGE BETWEEN THE TREATMENT ZONES AT THE BOTTOM, A SUBMERGED TRANSVERSE PARTITION MEMBER IN EACH SAID TREATMENT ZONE DIVIDING THE SAME INTO AN UPFLOW SECTION AND A DOWNFLOW SECTION LOCATED FORWARDLY FROM SAID UPFLOW SECTION; AIR DIFFUSER MEANS IN EACH UPFLOW SECTION FOR OXYGENATING AS WELL AS IMPELLING LIQUID UPWARDLY SUBSTANTIALLY OVER THE ENTIRE CROSS-SECTION OF SAID UPFLOW SETIONS TO EFFECT CIRCULATION BETWEEN THE UPFLOW AND THE DOWNFLOW SECTION; AND FLOW DIVERSION SHELF MEANS IN SAID FLOW PASSAGE MEANS TO PROVIDE FOR FORWARD FLOW PASSAGE ABOVE AND FOR REARWARD FLOW PASSAGE BELOW SAID SHELF MEANS, WHEREBY A PROTION OF THE LIQUID FROM THE DOWNFLOW SECITONS IS DIVERTED REARWARDLY AT THE TANK BOTTOM, AND WHEREBY THERE IS EFFECTED A CONTINUOUS COUNTERCURRENT MIGRATION OF BIOLIGICALLY ACTIVE FLOCS TOWARDS THE INFLUENT END OF THE TANK AS OPPOSED TO THE NET FORWARD FLOW MOVEMENT OF THE LIQUID TOWARDS THE EFFUENT END OF THE TANK.