Catalytic Wet Air Oxidation Of Simulated Condensate Wastewater And Hygiene Wastewater In Space Station

In this study, the simulated condensate wastewater and hygiene wastewater in space station were purified by catalytic wet air oxidation(CWAO) technology in trickle-bed reactor and stirred-tank reactor.The effects of the temperature,pressuer,catalyst dosage and stirring speed on the TOC removal rate were investigated in stirred-tank reactor experiments, and the mechanism and kinetic processes of the CWAO of condensate wastewater and hygiene wastewater were also analyzed. The results show that the temperature plays the most important role in the treatment process, the TOC removal rate rises with the increasing temperature. The pressure,catalyst dosage and stirring speed also have influence on the treatment effect in a certain range. The TOC removal rate could reach 96.01% after 11 h treatment of condensate wastewater at the condition of 120℃,0.6 MPa,catalyst dosage10 g and stirring speed 200 rpm. The TOC removal rate could reach 98.68% after 11 h treatment of hygiene wastewater at the condition of 120℃,1.2 MPa,catalyst dosage 10 g and stirring speed 200 rpm.The CWAO of condensate wastewater, hygiene wastewater and alcohol have the similar kinetic which proceeds in two steps: the initial rapid reaction period and the slow reaction period.In the initial rapid reaction period the easily degradable organic matters aremineralized directly or oxidized to the the intermediate products. In the slow reaction period the intermediate products are degraded. The kinetic experiments show that the TOC removal of condensate wastewater and hygiene wastewater can be described by the first order reaction equation.The degradation mechanism of condensate wastewater, hygiene wastewater and the typical contaminants(alcohol and acetic acid) was investigated by measuring the TOC、p H 、 ammonia concentration 、 conductivity and the concentration of acetic acid of the samples. The results show that acetic acid is the main intermediate in the degradation process of condensate wastewater, and alcohol. Acetic acid and NH4+ were main intermediates in the degradation process of hygiene wastewater.In the trickle-bed reactor experiments, the effects of the reaction conditions on the TOC removal rate were studied. The TOC removal rate of condensate wastewater could reach 94.5% after treatment at the condition of 140 ℃, flow rate of water 5 ml/min,flow rate of air 100 ml/min. The TOC removal rate of hygiene wastewater could reach92.2% after treatment at the condition of 120℃,flow rate of water 10 ml/min, flow rate of air 100 ml/min.