TREATMENT OF ORGANIC SEWAGE

摘要

PURPOSE:To prevent foaming in a non-dilution type biological nitrifying and denitrifying process by supplying a part of a powdery activated carbon coexisting flocculated sludge separated by solid-liquid separation treatment adding an inorg. flocculant and powdery activated carbon to the first biological nitrifying and denitrifying treatment process. CONSTITUTION:Residue-removed excretion 1 is supplied to a main biological treatment process 2 to perform nitrification, denitrification and the removal of BOD and the obtained activated slurry 3 is subjected to membrane separation by an ultrafiltration membrane 4 and membrane transmitted water 5 separated from conc. activated sludge 6 is sent to an auxiliary biological treatment process 7 to add a sludge dehydration filtrate 12 and various waste water 12 to said water 5 and return sludge 18 is separated in a solid-liquid separation process 16. Biologically treated water 17 receives the addition of an inorg. flocculant 19 and a pH control agent 20 to be stirred in a mixing tank 21 and further receives the addition of powdery activated carbon 22 to be mixed with said activated carbon 22 in a contact mixing tank 23 and highly treated water 26 is obtained by a solid-liquid separation means 25 while a part 27' of the separated powdery activated carbon coexisting flocculated sludge 27 is returned to the biologically treated water 17 and the remainder 27 is returned to the process 2. By this method, foaming is eliminated in the main biological treatment process and a defoaming agent can be reduced and an activated carbon tower also becomes unnecessary.