Experimental Study Of Quaternized Celluloses For Treating Activated Dyeing Wastewater

In view of the difficulty of decolorizing treatment of dyeing wastewater, wesynthesized quaternized celluloses (short for QCs) polymeric coagulant byquaternization reaction, explored the mechanism of QCs on dyeing wastewater andstudied the effect of adding inorganic coagulant on decoloration under different pHconditions, using MgSO4as coagulant. The results showed that QCs played a greatrole in decoloration of dyeing wastewater. In addition, we studied the treatmentperformance of dyeing wastewater and analyzed the effect of dosage and deliverymethod of drug, waste water flow, the G value of mechanical flocculation paddles andpH value of wastewater on the decoloration, according to mechanical flocculationlaboratory model made of organic glass and intermittent precipitation laboratorymodel. Then we obtained the optimal process parameters by orthogonal experiment,and studied the decoloration on dye wastewater with the coagulation under the bestconditions. The results were shown as follows:(1) When the pH value was about10, decolorization was the most significant andstable and QCs dosage had a critical impact on the decolorization rate and CODremoval rate. While adding the QCs, decolorization was significantly increased andthe coagulation sedimentation time was significantly reduced with the increase dosageof MgSO4. Average hydraulic retention time of mechanical flocculation reactor modelwas21min and average hydraulic retention time of precipitation reactor model was30min. When water flow of the system was288mL/min, as long as the dosage ofMgSO4was not less than150mg/L, decoloring rate can reach more than90%eventhough the dosage of QCs was in the range of120~200mg/L. When the flow ofmechanical coagulation precipitation reactor model fluctuated within a range of200~320mL/min, effluent color was still up to8times and COD value can still be reducedto33mg/L, which can meet the requirements of “textile industry reuse water quality(FZ/T01107-2011)” on the chromaticity and COD value of the reuse water. Whenwater flow of the system was288ml/min, flocculation parameters of the three gridflocculation were G1=99s-1, G2=58s–1and G3=25s-1, QCs dosage was180mg/L and coagulant MgSO4dosage was300mg/L, the effluent was best, itschromaticity can reach2times and its COD value can be reduced to8mg/L.(2) The delivery of QCs delayed the lag phase of Escherichia coli andStaphylococcus aureus. And the greater the concentration of QCs, the largermagnitude the lag phase of bacteria was extended. When the concentration of the QCswas250mg/L and150mg/L, the growth of the two bacteria will be completelyinhibited, which will be helpful to make sure the reuse of wastewater and water safetyduring long-term storage.