Equipment for the anaerobic purification of waste water

Abstract From the Canadian patent

To avoid considerable vertical and horizontal flows in the settler formed by gas collection hoods of the upflow, anaerobic sludge blanket (U.A.S.B.) reactor each gas collection, hood debouches at one or two ends into a gas collection chamber via one or more openings, the upper boundary of said openings being situated below the inside surface of the projection or the top of the hood concerned. The gas collection hoods are situated immediately below the level of the effluent discharge and the depth of the settler is shallow. As a result of the decrease in pressure only a few gas bubbles are consequently liberated and the settling of the sludge is not appreciably disturbed.