The Synergistic Effect Between Heat Treatment And Regeneration Disposal Of Water-softing Resin To Improve The Printing And Dyeing Sludge Dewatering Performance

The synergistic effect of regeneration disposal of water-softing resin and heat treatment on printing and dyeing sludge dewatering performance was researched.The residual activated sludge in the treatment system of printing and dyeing wastewater contains complex polymer and hydrophilic hydrolysis product,resulting in poor sludge dewatering performance.Before sludge mechanical dewatering,flocculation of the sludge,sludge concentration of suspended particles in larger,or form a flock,which speeds the coagulation of particles,achieve the purpose of solid-liquid separation,dehydration in favour of follow-up.Printing and dyeing enterprises typically use a large number of soft water,and the large amounts of wastewater that water softener equipments produces directly discharge into the environment,which generally contains so high salinity(high concentration of Ca2+ and Mg2+)that environmental risks are brought significantly.At the same time,high temperature and high pressure processing technology widely used in printing and dyeing enterprises can produce a large amount of waste heat.So with both organized,not only improve the dewatering performance of printing and dyeing sludge,but also realize recycling.Specific resistance of filtration(SRF)and capillary suction time(CST)are used to evaluate the sludge dewaterability,determining the synergistic effect of heat treatment and regeneration disposal of water-softing resin on the dewatering performance of printing and dyeing sludge,and the change of sludge dewaterability is explained by measuring variation of Zeta potential and FT-IR spectra of the sludge in the conditioning process.In this experiment,by measuring the values of specific resistance of filtration and capillary suction time of printing and dyeing sludge,determining how a single heat treatment effect on the dewatering performance of printing and dyeing sludge,and what is the optimum condition for printing and dyeing sludge dewatering,and how the length of heating time influence the dewatering performance of printing and dyeing sludge.In addition,by measuring the change of Zeta potential and FT-IR spectra to explore the mechanism of action that how the heat treatment and the regeneration disposal of water-softing resin acts in the sludge conditioning process.Finally,the flocculation effect of regeneration disposal of water-softing resin and the common cationic flocculants Fe Cl3 and Al2(SO4)3 were compared.This experiment shows: single heat treatment can make the printing and dyeing sludge dewatering performance worse;The optimum conditions for printing and dyeing sludge dewatering in the experiment as follows: when heating temperature is 70?,30 ml regeneration disposal of water-softing resin was added to 100 ml printing and dyeing sludge(the mass of Ca2+ in regeneration disposal of water-softing resin is about 11.9% of the dry sludge),specific resistance of filtration was reduced from 2.52×1011m/kg to 0.85×1011 m/kg,capillary suction time was reduced from 15.2s to 8.9s.And the heating duration had no significant effect on printing and dyeing sludge dewatering performance.An increasing Ca2+ dosage reduced the surface charge remarkably,and a higher temperature could strengthen this impact.The FT-IR spectra indicate that Ca2+ could interact with the protein and O-H functional group in the flocs.Research proves: this regeneration disposal of water-softing resin can be used as a flocculant,which was an effective method for improving the printing and dyeing sludge dewatering performance,also achieved a recycling.