ABSTRACT
The Deep Shaft process was invented by ICI of Great Britain. It is a high-intensity biological process for the treatment of sewerage and bio-degradable industrial wastes. It works by circulating the sewerage in a deep shaft, divided into two sections, a downflow; or downcomer and an upflow; or riser section. The Deep Shaft unit replaces or supplements the aeration basin in the activated sludge process the purpose of which is to support the biological purification of effluents. Raw wastewater and returned activated sludge are fed continuously to the downcomer and mixed with the very much larger volume of liquor recirculating within the shaft. The Deep Shaft process is a biological treatment system employing the activated sludge concept. Brewery wastewater flows into a wet well from which it is distributed between the extended aeration plant and the Deep Shaft plant. The Numazu wastewater treatment facility treats a high strength fish processing wastewater in a dual shaft design operating in series.
