Sewage treatment by activated sludge in pressurised vessel - contg. movable sponge-like structures to which micro-organisms can attach

摘要

A plant for treating sewage with activated sludge, is arranged to mix thoroughly, prefiltered sewage in a closed aeration vessel containing flocculent sludge and a developed bacterial culture, with air fed in continuously and maintained in the zone above water level, at a pressure of =2 atm. the sludge being sepd. from the purified water and returned to the pressure vessel after the excess growth has been removed. In the container, structures to which mass of bacteria and colloids can become attached, are provided in the form of blocks of expanded polystyrol together with compression devices. The volume of the spongelike blocks is raised and lowered, so that air is sucked into them above water level and expelled from them below the water level, alternately. Gives high oxygen input with relatively low expenditure of energy. No turbulence to damage the activated sludge which absorbs the colloidal impurities is present, thorough mechanical cleaning is also obtd.