WASTE WATER RECOVERY AND REUTILIZATION

摘要

PROBLEM TO BE SOLVED: To obtain a waste water-recovering water used in large quantities to reutilize the same as raw water in the production of pure water or general service water such as supply water of a cooling tower. SOLUTION: NaOH is added to waste water containing silica in concn. near to saturated solubility from a chemical injection device 1 to adjust the pH thereof to 9 or more. The pH adjusted waste water is supplied to a distiller 2 being a steam ejector type triple-effect evaporator. Distilled water of the evaporator 2 is stored in a treated water tank 3 and a part thereof is sent to a boiler 4 and steam obtained herein is supplied to the stem ejector of the above evaporator 2. The condensation of steam in the evaporator is performed by cooling water coming from a cooling tower 5. The distilled water of the evaporator 2 has high purity of conductivity of 10μS/cm or less. The conc. water of the evaporator 2 is sent to an existing waste water treatment equipment to be mixed with other waste water to be properly treated and discharged.