The Disposal system of dyeing wastewater

摘要

The present invention relates to a dyeing wastewater treatment method, comprising: a first pretreatment for subjecting introduced alkaline dyeing wastewater to Fenton reduction by adding a small amount of an iron salt thereto; a second biological treatment for neutralizing and aerating the first pretreated dyeing wastewater to activate microorganisms to degrade organic matters; a third Fenton reduction treatment for adding an iron salt to the dyeing wastewater in a strong alkaline state to remove non-degradable contaminants; and a fourth Fenton oxidation treatment for introducing an iron salt into the dyeing wastewater in a strong acid state to finally remove remaining non-degradable contaminants that are difficult to remove by the biological treatment and the Fenton reduction treatment, and adjusting the pH to 7.5 before discharging the treated dyeing wastewater. In particular, if the strong acid state is maintained by introducing sulfuric acid into reduced iron salt precipitates formed from a reaction between the non-degradable contaminants and the iron salt in the second Fenton reduction treatment, iron components in the precipitates are dissolved in sulfuric acid, thus separating the dyeing wastewater into an overlying iron salt solution and sludge. The overlying iron salt solution is recycled in each of the processes that involve iron salt additions, and the precipitates are dehydrated along with precipitates formed during the Fenton oxidation treatment into dehydrated cake and discharged.