PURPOSE: For simultaneous and economical separation of BOD and phosphorus from waste water, the waste water containing the same is transformed into calcium salt in an exposing bath having solid phase consisting of cement and lime.
CONSTITUTION: Water water containing BOD and phosphor such as urban sewage or food waste is treated in an air exposing bath 1 having solid phase 17 of cement and lime massive mixture. When the exposing bath is adjusted to pH 7.8 to 9, phosphate ions in waste water transforms into calcium salt. The formed calcium salt is adsorbed by active sludge and extracted from the bottom of the settling bath 2. Next, the sludge treating bath 3 is adjusted to a pH 5 to 7 to discharge the adsorbed calcium phosphate into solution as phosphate ion. Thereafter, active sludge is returned to the exposing bath 1 to coagulate phosphate ions for separation. Thus, BOD and phosphor in waste water is simultaneously and economically removed.
UESHIMA HIROSHI
FUJII TOSHIROU
| JP45033595A | ||||
| JPS5168974A | 1976-06-15 |
| US3522171A | 1970-07-28 |