Effects Of MW-Fenton On Textile Dyeing Sludge Disintegration And Dewaterability

The textile dyeing sludge is a kind of typical industrial solid waste. Its moisture content reaches up to85%after common mechanical dewatering. Since the cost of the reduction treatment is about60%of the total treatment, the reduction treatment of the textile dyeing sludge has been the key to the subsequent disposal. Fenton reagent is one of the strong oxidier, it can disintegrate the extracellular polymerci substances in the sludge, in which the bonding water will be released. Thus, the dewatering performance of sludge can be improved. And the basic theory problems about oxidating sludge by Fenton and MW-Fenton have been done in this study, also exploring for the relationship between the extent of disintegrating sludge and the dewaterability.In this work, Fenton oxidation was used in preprocessing for textile dyeing sludge by optimal experimental. The change of the dewatering performance index such as TSS, VSS, CST and SRF were studied. The experiment parameter such as the pH, dosage of H2O2and Fe2+, reaction time and reaction temperature were also optimized. Based on the experimental results, the operation conditions were optimized with pH of2.0, H2O2dosage of428mg/g (dry solids), Fe2+dosage of42.8mg/g (dry solids), reaction time of1.5h and reaction temperature of80℃. The value of TSS decreased from18.66g/L to4.82g/L, the removal efficiency of TSS was74.17%. The value of CST and SRF decreased from98.6s and6.03×1011s2/g to18.9s and8.42×1010s2/g, respectively. The average particulate diameter and the median particulate diameter of the sludge changed from53.8μm and42.9μm to19.8μm and16.2μm, respectively. All above provided the new theory and technology for the dewatering reduction of the textile dyeing sludge.Due to the advantage of microwave, such as clean, apid, control easily, Microwave, instead of the traditional heat treating, was used to combine with Fenton reagent to oxidate sludge. Compared with the traditional heat treating, microwave present a more obvious advantage for the sludge dewaterability. To continue investigating the effect of experimental factors on treating sludge. Based on the experimental results, the operation conditions were optimized with pH of3.5, H2O2dosage of80mg/g(dry solids), Fe2+dosage of10mg/g(dry solids), reaction time of2.0min under the microwave power of648W. Within the present experimental condition used, the concentration of protein, polysaccharide and DNA in the sludge supernatant were328mg/L,114mg/L,37mg/L, respectively, the increases in the levels of protein, polysaccharide and DNA in the sludge supernatant were210%,142%and122%, respectively, compared with the raw sludge; the concentration of SCOD in the sludge supernatant was675mg/L and its removal rate was9.6%, thus the increase in the level of SCOD in the sludge supernatant was230%; sludge viscosity was2.16mPa·s, whose removal rate was89.4%; the value of CST and SRF were12.2så'Œ4.89×1010s2/g, respectively, whose removal rates were82.8%and87.1%, respectively. After the sludge disintergration by MW-Fenton under the optimal conditions, yielding maximum sludge dewaterability characteristics by generating sludge with optimal the whole solution content (350mg/g～400mg/g and450mg/g～500mg/g) and DDSXOD%(7%～8%and8%～9%).