The Technology For Treating Cyanide In Printing Dye Wastewater

N-phenylacetonitrile chemical wastewater containing a variety of unbiodegradable, and water-soluble material,Such as Cyanide, aniline. In this article, the author did some pilot study of treating cyanide and other materials in this wastewater,and seek a reasonable treatment process, in order to provide some help which can be used to treating similar wastewater. For its characteristics of high concentration of organic and unbiodegradable, the physico-chemical treatment and biological treatment method are combined using by the author for wastewater treatment.First of all,in the experiments of pretreatment,several coagulating agents are compared and then the best one was selected.At the same time,the coagulating conditions in the lab were optimized as well.under the best conditions,the content of COD of the wastewater decreased about 15.2%,SS decreased about 71.1%, reduced the burden of follow-up treatment.Secondly,using Alkaline hydrolysis solution and chemical precipitation to decrease NH3-N to achieve better results.We find the best reaction conditions by using Alkaline hydrolysis solution. Control the temperature between 30℃to 35℃, and adjust pH value between 11 to 12, react two days or so, NH3-N removal rate reached 61%. Using the chemical precipitation method, we found that when control the reaction time within an hour and adjust pH value between 9 to 9.5,and the amount of MgO is 2.6 times to H3PO4, we can achieve the optimal reaction conditions,and NH3-N removal rate reached 90.2%,then NH3-N can be disposed by microorganism.In the experimental studies of cyanide treatment, selecting the chlorine dioxide as oxidant and then by oxidation reactions, control the reaction temperature between 65-70C°and adjust pH value to11, cyanide concentration in the wastewater can be reduced from 990mg / L to 100.4mg / L. Finally, in the biological treatment process, using activated sludge dispose those residual cyanide and NH3-N, and add to the dominant bacteria into the activated sludge(1008# bacteria),and acclimate activated sludge, CODcr in wastewater stabilized at around 450mg/L-550mg/L.Finally, maximum toleranced value of the activated sludge for cyanide is 9.5mg/L and residual NH3-N is 27mg/L.