TREATMENT OF EXCRETION-BASED SEWAGE

摘要

PURPOSE:To easily treat the title sewage by adding an inorganic flocculating agent to activated sludge slurry which has been treated in a first and second biological nitrating and denitrifying stages and performing solid-liquid separation for the mixture. CONSTITUTION:Excretion residue 3 is mixed with excess activated sludge 5 flocculated by an inorganic flocculating agent in a mixing tank 6 and thereafter a dehydrating auxiliary 7 such as the cationic and nonionic high molecular flocculating agents is added. The mixture is fed to a sludge dehydrator 8 and separated into low-water dehydrated cake 9 and filtrate 10. Excretion 4 separated from residue is fed to an undiluting biological nitrating and denitrifying treatment tank 12 from a storage tank 11 and nitrogen component not less than 90% is removed by microorganisms. Both activated sludge slurry 14 discharged from the main biological reaction tank 12 and waste water incorporating filtrate 10 as main body are introduced into a biological nitrating and denitrifying tank 15 and sludge component remaining in activated sludge slurry 14 is removed. Thereby the title sewage can be treated without lowering reaction velocity.