| 摘要 |
PURPOSE:To enable the conservation in the cost of chemicals, in a process for performing the chemical softening treatment to Steffen waste water and subsequently applying anaerobic biological treatment thereto, by performing the chemical softening treatment by utilizing the inorg. carbon compound formed by the anaerobic biological treatment. CONSTITUTION:In performing chemical softening treatment to the Steffen waste water discharged from a beet sugar factory or waste water containing said Steffen waste water in a first stage and subsequently applying anaerobic biological treatment 5 thereto in a second stage, the chemical softening treatment is performed by utilizing the inorg. carbon compound formed by the anaerobic biological treatment. That is, because it is unnecessary to supply said inorg. carbon compound from the outside in performing the chemical softening treatment, the cost of chemicals can be conserved to a large extent and, because the inorg. carbon generated in the process is converted to a solid substance as CaCO3, the gaseous composition generated by the anaerobic treatment is rich in CH4 and the enhancement in the calorie of said composition is promoted. |
