BACKWASHING METHOD OF FIXED BED TYPE SEWAGE PURIFYING TANK

摘要

PURPOSE:To perform backwashing at optimum time, by detecting the change in the flow velocity of a recirculated stream generated in the barrier plate of a strain type flow velocity sensor provided to a sewage purifying tank as the change in strain generated in a strain gauge. CONSTITUTION:Waste water enters an anaerobic fixed bed type purifying tank from an inflow pipe 4 by operating a pump 14 and stored therein as shown by A. The digestion gas B generated in the upper part of the tank is emitted into waste water A from a diffusion apparatus 9 by driving a compressor 10 to recirculate the waste water A to a direction C. When the recirculated stream C passes a packing material 8, the org. compound contained therein is decomposed under anaerobic condition by microorganisms based on methane fermentation bacteria adhered to the surface of the packing material 8 and the digestion gas B based on methane gas and carbon dioxide is formed and accumulated in the upper layer part of the tank. Excessive digestion gas B is exhausted out of the tank from an exhaust pipe 7.