Study And Application Of ClO₂ And Electrochemical Method In Disinfecting Hospital's Wastewater

Hospitals are the patient-concentrated places, where people risk catching all kinds of bacteria, viruses and pathogenic-micro-organism spread by the means of air and water, thus causing hospital infection and spread of infectious diseases. Hospital infection has increasingly become the problem of common concern. The answers to curbing the spread of diseases, controlling the infectious diseases and preventing hospital infection are disinfection and bacterium-killing. Countries throughout the world attach great importance to the disinfection and treatment of polluted water. Law of the People's Republic of China on Prevention and Control of Water Pollution stipulates that bacteria- virus- and pathogen-contaminated water may be discharged only after it is disinfected to meet the relevant hygiene standards of the State.Chapter One is an overview of hospital's wastewater. It also gives a general account of the classification and mechanism of electrochemical disinfection and the remaining problems as well as the properties, mechanism, preparation and testing method of ClO₂ serving as disinfectant. In Chapter Two, the properties of using ClO₂ to treat the wastewater discharged from hospitals are studied. The optimal parameters of the quantity of ClO₂ input, the temperature of wastewater, reaction time, pH and stuffing types are established by improving the technological process and by using orthogonal test. It also discusses the influence of all these parameters on destroying CFU. Chapter Three mainly studies the improvement of traditional testing method of ClO₂. In this study, ClO₂,Cl2,ClO₂^-,ClO₃^-were determined respectively by controlling pH and using stabilizer, activator and masking agent. In Chapter Four, a study was carried out to observe the germicidal efficacy and toxicity of three components Chlorine Dioxide disinfection powder. The influences of different factors on the disinfecting effect of ClO₂ are also analyzed. Chapter Five is a study on the disinfecting mechanism of electrochemical disinfection method by changing anode materials and electrolysis. It analyzed the influences of cathode, current density, hydraulic retention time, air flow rate, the rate of anode effective area to the inner water volume on disinfecting effect.To sum up, the study makes it clear that ClO₂ disinfection powder, as a non-toxic and slight-irritant disinfectant, is quite effective in destroying the vegetative forms of bacteria and bacterial spores. The resulting parameters from the study of electrochemical disinfection method are of practical value.