Analysis On The Exhaust From Medical Waste Steam Sterilization Equipment And Research On Its Photocatalytic Degradation

High-temperature steam sterilization was widely used to dispose the medical waste in recent years in China to eliminate or restrict the production and emission of persistent organic pollutants in waste disposal process. Through the current domestic operation of this technology, volatile organic compounds(VOCs) and odor emissions has been one of the main obstacles in constraint of non-incineration facilities meeting the best available techniques and environmental practice requirements.Firstly,the composition, physical and chemical properties of medical waste in different cities of China are collated and analyzed. In the view of the situation in the high-temperature steam process, the sterilization room condenser water was sampled in the sterilization process at different stages of sterilization process,and VOCs of the samples were detected by P&T-GC-MS, then the composition and contents of the exhaust gas were calculated by the principle of gas-liquid equilibrium. Small amounts of benzene, halogenated hydrocarbons, naphthalene, dimethyl disulfide, ethyl acetate and other components were detected. Through analyzing the physical and chemical properties and the disposal process of medical waste, two kind of mechanisms for production of VOCs were proposed, in which one is the growth and metabolism of microorganisms during medical waste storage and transportation, the other is the high temperature steam purge of medical waste in the pulsating evacuation.In this paper, photocatalytic degradation of the typical exhaust,benzene and toluene,were studied. To enhance the adhesion of P25 on the aluminum plate, polyvinyl alcohol solution and silica sol were added to the P25 suspension, which increase the adhesion of TiO2, meanwhile decreased the activity of P25. Photocatalytic degradation curves at different initial concentrations , reaction area and light sources were investigated. The results show that the degradation rate constant decreased with the increase of the initial concentration. The conversion rate increased with the expansion of catalytic area and degradation rate at 253.7nm wavelength was better than that at 365nm. Absorption competition appeared and catalyst deactivation phenomena existed in the degradation of benzene and toluene, catalyst regeneration was also explored in our work.