Method and apparatus for treating fluid material with suspended solids

Claim 1

A METHOD FOR TREATING FLUID MATERIAL CONTAINING SUSPENDED PARTICLES, COMPRISING THE STEPS OF ACCUMULATING A PREDETERMINED QUANTITY OF THE MATERIAL IN A CLOSED RECEIVER HAVING AN OUTLET ADJACENT ITS LOWER LEVEL, AERATING WHILE DISCHARGING SAID PREDETERMINED QUANTITY OF FLUID MATERIAL BY INTRODUCING PRESSURE AIR INTO THE RECEIVER AT A POSITION BELOW THE LEVEL OF FLUID THEREIN WHILE CONTINUOUSLY VENTING THE RECEIVER ABOVE THE LEVEL OF THE FLUID MATERIAL, SAID CONTINUOUS VENTING BEING AT A RATE SUBSTANTIALLY LOWER THAN THE RATE OF FLOW OF PRESSURE AIR INTO THE RECEIVER SO AS TO ACHIEVE SUFFICIENT PRESSURE ON THE UPPER LEVEL OF FLUID MATERIAL TO DISCHARGE THE MATERIAL THROUGH THE RECEIVER OUTLET, DELIVERING THE AERATED FLUID MATERIAL INTO THE LOWER PORTION OF A REGION OF LOWER PRESSURE, WHEREBY THE SLUDGE PARTICLES ARE CONCENTRATED IN THE UPPER PORTION OF THE REGION AND THE AIR IN EXCESS OF SATURATION IS RELEASED FROM THE FLUID MATERIAL, SKIMMING THE SLUDGE PARTICLES FROM SURFACE OF THE REGION INTO A COLLECTING TROUGH, AND BAFFLING THE REGION OF LOWER PRES-