Research On Treating And Reusing Wax Printed Washing Wastewater By Microwave Electrodeless UV Lamp And Photocatalytic Oxidization

There are large quantities of refractory materials in washing wastewater of wax printed painting such as dyes, auxiliaries, sizing agent (sodium alginate for example) and so on. The washing wastewater contains high COD and high chroma, and its heat losses seriously. It will cause great harm to our environment if exhausting the washing wastewater. The economic losses such as heat loss and water loss and so on will be inestimable. If we can treat and reuse such wastewater, and to reuse its heat, the economic benefit and environmental benefits will be very considerable.In this paper, through the intensive establishment of a combined process "pretreatment" and "Microwave Electrodeless ultraviolet ray Multi-catalyzed oxidation", to treat with simulating wax printed wastewater (reactive brilliant red X-3B/ sodium alginate) through coagulants and UV/H₂O₂/O₃. We studied the effect of this method to decolorization and the removal of COD, and studied its influencing factors and conditions optimization, with the use of appropriate experimental technique. We carried out mechanism analysis and finally enlarged to the pilot experiment scale; we did research about the wax printed washing wastewater treatment of the factory and had achieved good results the results show that:(1) The best concentration of the simulated wax printed wastewater of this flocculation experiment is: the concentration of reactive red X-3B and sodium alginate both were 1g / L. When the dosing of PAM, PAC and double salt were 0, 150mg/L, 25mg/L separately, flocculate the simulated wax printed wastewater which is 2L, 1g/L, the decolorization rate and the removal rates of COD reached 82.7% and 46.3% respectively. It is feasible for PAC, PAM and double salt to pretreat the simulated wax printed wastewater.(2) The best dosage of UV/H₂O₂/O₃ is determined through the condition optimization experiments. UV/H₂O₂/O₃ method can accelerate the decolorization of the flocculent supernatant liquid of simulated wax printed wastewater in acidic conditions, the decolorization rate reached as high as 98.9%, the removal rate of COD is a little lower; using this method in alkaline conditions, the removal rate of COD reached 52.3%, the removal efficiency of COD is superior to other methods. When used simultaneously, UV and H₂O₂ + O₃ have a better degradation effect, because the two have a synergistic effect.(3) Using an enhanced combination of processing of "pretreatment" and "Microwave Electrodeless ultraviolet ray Multi-catalyzed oxidation"to treat a high-temperature wax printed washing wastewater enterprise. The system operated for 2 months and the results indicated that the chroma was stable at 16 times lower; the COD was reduced to 100mg/L below; pH value was stable at around 7; the water temperature fall 10-15℃merely and was stable at 45-55℃. We used the above process to treat 240 tons of waste water and recycled thermal energy, the system is running well, the effluent water was stable, and we can achieve the main target of the requirements of the enterprise reuse. The final effluent recycled to the washing process of the wax printed cloth and a series of tests showed that, finished fabric had no staining conditions; the chromatic light and the brightness were all well. The dry friction fastness was between 3 and 4; the wet friction fastness was between 3 and 4; the ironing fastness was between 4 and 5. Washing by tap water and reused water to the same cloth sample, all kinds of circumstances were in accordance with each other by comparison and after the factory′s acceptance to the sample chart. We can greatly save the production cost if we use the process to treating and recycling. The costs will be recovered by one set of equipment in a year and will gain about 1 million yuan per year; there are significant economic benefits. We can also reduce the discharge of wastewater and the environmental pollution.