Process for converting urban wastewater into easily biodegradable material

摘要

Process for converting urban wastewater into easily biodegradable material A process is proposed which comprises treating an urban wastewater (UWW) in the following stages: A) screening and/or desanding and/or degreasing, B) microsieving or primary settling of suspended solids in the UWW using relatively high ascent velocities, C) acid fermentation of the effluent in the stage prior to a fixed or fluidized ascending flow bed in an anoxic reactor operating with a low ascent velocity. This fermentation is assisted by the incorporation of soluble substrates originating from hydrolysis of the solids accumulating in the lower part of the reactor which does not contain substrate material. The effluent from stage C comprises the UWW already conditioned so that through the use of alternating anoxic/oxic (A/O) activated sludge systems nitrogen and phosphorus can be removed. Likewise the solids produced in B and C are incorporated into the sludge line in these systems.