| 摘要 |
PURPOSE:To permit the removal of heavy metals and fluorine without adding caustic soda and slaked lime or by reducing the added amounts, by providing a heavy metal removal device for adding fly ash to desulfurized wastewater, a COD treatment device therefor and a device for removing nitrogen compounds therefrom. CONSTITUTION:Desulfurized wastewater 1 stored in a tank 2 is sent to a heavy metal removal device 150 to which fly ash 5 is added, so that the pH value of the wastewater in a reaction tank 3 will become 6-8 when measured by a pH meter 12. A coagulant 102 is added thereto before being sent to a settling tank 4 and the hydroxide and fluorine compounds of precipitated heavy metals are removed as sludges 7 from the bottom of the settling tank 4. The supernatant water in this settling tank 4 is first sent to a COD treatment device 9 and then after COD removal to a nitrogen compound treatment device 10 for nitrogen component removal. The wastewater 11 thus treated is discharged or can be reused. |
