Emergency Treatment Of High Chroma Reclaimed Water Decolorizing

Though after advanced treatment,high colore raw reclaimed water can cause high colore treatment water which can't meet the national standards,such as GB/T19923-2005 or SL268-2006.That will cause sensory displeasure and affect the reuse.In this article,new cationic flocculating decolourants are created by using orthogonal tests.Simulate the high chroma of raw water by putting into three kinds of dyes to exam the treatment effects of decolourants.Main researches are as follow:Firstly,based on the mechanism of dyeing as well as the decolorizing mechanism of dicyandiamide-formaldehyde flocculant,choose urea and melamine as reagents because of the similar molecular structure to create new resin.Ammonium chloride or sulphuric acid is used as modifying agent,and then study on the decolorizing effects.The results show that urea-formaldehyde resin(UF),melamine-formaldehyde resin(MF)and dicyandiamide-formaldehyde resin barely have decolorizing abilities themselves as well as the modified UF.But for ammonium chloride as a modifier of MF,ammonium chloride or ammonium sulfate as a modifier of dicyandiamideformaldehyde resin is concerned,the decolorizing ability has improved significantly.But the decolorizing abilities have improved significantly with modified MF and modified dicyandiamide-formaldehyde resin.The decolorizing effects when they treating the acid or reactive dyes wastewater of low concentration can reach over 50%,but the former is more advantageous in turbidity removal.Secondly,using the orthogonal tests to choose optimal decolourant,and study on the influence of water treatment parameters,such as water temperature,pH,decolourant dosing,coagulant dosing and dosing sequence of decolourant and coagulant.Next,the removal rules of direct dyes are studied.The results show that,without adding decolourant,the dyes can achieve good removal only by using coagulant.With the increase of the coagulant dosing,the decolorizing effects and turbidity removal of direct dye wastewater tend to rise as a whole.Adding decolourants can't improve the removal efficiencies.Finally,use the pilot test equipment to study on large-scale water treatment effects.Then infrared scanning spectrum group analysis is carried out on the decolourants to help finding the decolorizing mechanism.The result of pilot test verifies the conclusion of laboratory test,and infrared spectrum shows that after adding ammonium modifier,decolourants react more fully to generate more products.Modified MF and dicyandiamide-formaldehyde resin have more amide groups and primary amine groups then UF,which are advantageous to decolorizing.Therefore,the decolorizing effects of modified MF and dicyandiamide-formaldehyde resin are more excellent then the UF.