Study On Printing And Dyeing Wastewater Treated By Magnetic UASB-MBR System

The water emission of printing and dyeing industry is very large. Because of thehigh content of refractory organic matter, high chromaticity, complex properties, andthe carcinogenicity, teratogenicity, mutagenicity of polycyclic aromatic hydrocarbonssuch as naphthalene and phenanthrene as well, the study of printing and dyeingwastewater aroused the attention of the researchers. The weak magnetic field effect ofmagnetic carrier can improve the ability of microbial metabolism, In the biologicaltreatment process of printing and dyeing wastewater with magnetic carrier, thetreatment effect is significantly improved.This study draws a significant attention ofresearchers. The magnetic carrier UASB-MBR system had been built in this paper fortreating wastewater containing Reactive blue5(K-GR for short). The processparameters and its removal efficiency were also studied in this paper. By shakerexperimental, the effect of magnetic carrier on K-GR removal in an anaerobiccondition and the optimal pH, MLSS, and initial dye concentration of this system wasinvestigated under the conditions of37℃. Moreover, Kinetics of this system treatingprinting and dyeing wastewater was discussed. Using the optimum conditions byexperiments, the degradation effect of naphthalene, phenanthrene, COD andchromaticity is discussed.The possible mechanisms of degradation of naphthalene andphenanthrene were studied by means of GC-MS analysis as the influent was actualproduction of printing and dyeing wastewater. Through the experiments, the followingconclusions were drawn:(1)Compared with single sludge, When the sludge concentration was3gVSS/L,intial pH was8.0, The optimal conditions of100mg/LK-GR wastewater treated，COD removal rate of magnetic carrier anaerobic microbial system can be increased13%, the chroma removal rate can be increased11%.(2)When the HRT was24h,sludge concentration was3gVSS/L, intial pH was8.0, The optimal conditions of100mg/LK-GR wastewater treated by magnetic carrieranaerobic microorganism system was the amount of10%of the container volume.The removal rate of COD and chroma all reached95%, naphthalene and phenanthrenereached80%and75%respectively.(3) The decolorization of K-GR in the magnetic carrier anaerobic system, are in line with first-order kinetics, correlation coefficient R2value was0.9637and Thereaction rate constant k1of9.685×10-2h-1under the best conditions.(4) In the actual wastewater was treated,the operation of magnetic UASB-MBRcombined system is stable. When the HRT was24h,sludge concentration was3gVSS/L, intial pH was8.0, magnetic carrier anaerobic microorganism system was theamount of10%of the container volume.The wastewater of chroma was400timesmore than、COD at1200-1600、naphthalene at9.0-14.0ug/L、phenanthrene at2.5-6.0ug/L was treated,The removal rate of COD reached95%, chroma reached90%,naphthalene and phenanthrene reached75%and70%respectively.(5) Analysis by GC-MS spectra of naphthalene and phenanthrene degradationpathway, in the process of its degradation both salicylic acid pathway and phthalatespathway.