TREATMENT OF WASTE WATER OF WET EXHAUST GAS DESULFURIZATION APPARATUS

摘要

PURPOSE:To recover the halogen compound and COD causing substance in waste water as an insoluble solidified substance by adding an alkali metal or alkaline earth metal-containing compound and coal ash to waste water wherein chlorine is conc. after electrodialysis and drying the waste water. CONSTITUTION:In a waste water treatment process, waste water is separated into a desalted solution and a chlorine conc. solution at first in an electrodialyzer 13 and the desalted solution is sent to an absorbing tower 5 through a line 14 to be reutilized while the chlorine conc. solution is sent to a mixing apparatus 16 through a line 15. Coal ash from a line 17, lime from a line 18 and gypsum from a line 19 are added to and mixed with the chorine conc. solution in the mixing apparatus 16 and the resulting mixture is sent to a drying apparatus 20 and a part of the exhaust gas from a boiler 1 is introduced into the drying apparatus 20 through the line 21 branched from the exhaust gas line 2 on the downstream side of an electric precipitator 3 to be brought into contact with the aforementioned mixture and reacted therewith to dry the same to obtain a disposable solid 23. The used exhaust gas is again returned to the exhaust gas line 2 through a line 22.