Long vertical shaft bioreactor with modified waste liquor injection

摘要

An improved method and apparatus is provided for the treatment of sewage waste in a long vertical shaft bioreactor wherein waste sewage is caused to circulate under air injected oxidizing conditions around a loop comprising adjacent riser and downcomer chambers connected at their upper and lower ends. The improved method comprises the steps of introducing influent waste at depth into the riser chamber at a point higher in the riser than the point of air injection and withdrawing treated effluent from the riser at a point lower in the riser than the point of air injection. A separation chamber may also be operatively connected to the riser chamber to recover sludge for return to the bioreactor. The method provides an improvement in oxygen uptake rate and reduces the anoxic zone in the reactor thus providing additional capacity for BOD5 removal.