TREATMENT OF WASTEWATER WITH HIGH COD CONCENTRATION

摘要

PURPOSE:To heighten the treatment efficiency by adding a mineral acid to wastewater with high COD concentration of a fixing solution, a developing solution, or their mixture and controlling pH at a specified level to isolate elemental S and then leading the filtered wastewater to an activated carbon tower and adding an alkaline agent to a solution which is the wastewater comes out of the tower to neutralize the solution. CONSTITUTION:A fixing solution, a developing solution, or their mixture is an object to be treated. At first, a mineral acid is added to the wastewater with high COD concentration and pH is adjusted to be 1-1.5. S of KCNS, Na2SO3, NaSH, etc., is isolated as elemental S. Further, air stirring is carried out to grow flocks and discharge SO2 gas and at the same time filtration separation is carried out to lower COD of the solution. Then, the filtered solution is continuously led to a large number of activated carbon towers to adsorb COD and organic complexes. Next, an alkaline agent is added to the solution which comes out of the towers and the resulting solution is neutralized to remove COD. After that, in the same way of a conventional method, NaClO is added to the filtered solution at about 10% of the treatment solution and the supernatant liquid is diluted or discharged directly to a river.