Vertical drainage drying bed for waste sludge and an intensified method of treating wastewater

摘要

A drying bed for waste sludge in a wastewater treatment facility having a vertical drainage riser extending vertically from a subnatant discharge pipe near the bottom of the drying bed. A sludge inlet at an end of the drying bed communicates with a source of watery sludge. Water communicates through a mesh screen that wraps the vertical drainage riser and through openings in the vertical drainage riser to the subnatant discharge pipe. A valve is selectively opened to control the flow rate of the water from the subnatant discharge pipe. A method of dewatering waste sludge is disclosed. The wastewater treatment facility provides a mixing/balancing chamber for initial mixing of activated return sludge with influent wastewater for aggressive assimilation of wastes and an improved airlift for removal of suspended solids in the wastewater. The airlift comprises a solids evacuation pipe having a lower open end for receiving solids, an upper open end for exiting solids, and a midsection defining a series of holes. A sealed manifold encloses the midsection of the solids evacuation pipe. An air supply line connects at one end to a supply of pressurized air and the other end connects to the interior of the manifold. The air, being introduced through the holes into the solids evacuation pipe, produces lift for causing the solids to enter the lower open end of the solids evacuation pipe and to exit the upper open end of the solids evacuation pipe.