Patent ID: 6224769
Filing Date: 2001-05-01
Classification: C02F,Y02W

Abstract:
A method of biologically treating an organic waste water, comprising the steps of:biologically treating the organic waste water im a biological treatment device;solid-liquid separating the waste water treated in the biological treatment device into a treated water and a sludge by a solid-liquid separation device;returning a portion of the sludge separated by the solid-liquid separation device to the biological treatment device;concentrating at least a portion of a residual sludge by a concentration device; andsolubilizing the concentrated sludge by an aerobic thermophilic bacteria in a solubilizing tank,wherein the solubilizing treatment is performed using heat and under the conditions such that a sludge solubilization enzyme is produced and secreted from a microorganism and the solubilization is promoted by the enzyme and a time requirement for the solubilizing treatment is determined based on a hydraulic residence time of the treated liquid in the solubilizing treatment device.