| 摘要 |
PURPOSE:To make it possible to use recovered liquid again by heating waste liquid to be treated in an evaporating kettle under reduced pressure condition, and adjusting pH thereof. CONSTITUTION:Waste liquid to be treated of non-silver salt sensitive material is heated in an evaporating kettle 2 under reduced pressure condition, solvent is evaporated to be cooled, and liquidized solvent is recovered into a liquid receiving vessel 20, and pH of that recovered liquid is adjusted. Namely, in a control mechanism, a pH measure and a stirrer 28 are operated, when liquid level in the liquid receiving vessel 20 detected by a liquid level sensor 21 is higher than a specified level, and a signal measured by the pH measure is compared with a range of setting values previously stored. Then, if it is in a range of set values, a liquid sending pump 22 is operated for a fixed time, recovered liquid in the liquid receiving vessel 20 is sent to a recovering tank 40, and when the set value is higher out of the range, an electromagnetic valve 25a is opened to drop acid material to the liquid receiving vessel 20 from an acid material dropper 25, and when set value is lower out of range, an electromagnetic valve 26a is opened, and alkali material is dropped to the liquid receiving vessel 20 from an alkali material dropper 26. |
