| Sewage reclamation is an important means to alleviate water shortage, and choosing recycled water disinfectants and disinfection process is important for reducing the ecological risks of reclaimed water. This research took two typical sewage treatment plant process in HaiKou city as the research object and used the toxic effects of model organism zebra fish exposed as detection index, to carry out the experiments comparing the typical disinfection processes of sewage reclamation and filtering disinfectants.This research includes:①This experiment took XAD-8, Bio-RADAG-MP-50, DuoliteA-7resin combined method to decompose recycled water dissolved organic matter into6kinds of ingredients on the basis of the charge and polarity differences. Used the toxic effects of model organism zebra fish exposed as detection index, through researching the all kinds of ingredients sodium hypochlorite disinfection byproducts and its toxicity effects relationship to apprise feasibility of classification method.②This experiment took typical disinfectants such Sodium Hypochlorite, Chloramines, Chlorine Dioxide, Ozone and Ultraviolet as the research object. Toxicological characteristics of zebra fish embryos include Heart rate ratio, hatchability and malformation rate and typical three kinds of chlorine disinfection and ozone disinfection were compared and selected through this characteristics and disinfection of UV disinfection combined was also researched. Sodium Hypochlorite and Chlorine Dioxide were used as disinfectants to research and compare the sewage treatment processes including conventional activated sludge process and Hypoxia/Aerobic denitrification process.③Sodium Hypochlorite and Chlorine Dioxide were used as disinfectants to research and compare the sewage treatment processes including conventional activated sludge process and Hypoxia/Aerobic denitrification process. Concluded as follows:1. This experiment used3kinds of resin to dissociate recycled water DOM, and adsorption and dissociation were well. Adding disinfectant Sodium Hypochlorite to the various components, Control concentration0,1.0,2.0,5.0mg/L. Components HON, DIM, HIA, HIB and HIN resulted in100%embryos mortality rate and the embryos of other components didn’t all die. Tested water samples had serious nonfatal on zebra fish embryos including the each component solution pH and excess backwash solution ingredients from backwash process. Impurity removal method is so difficult and inefficient that these components couldn’t be used in Toxicology research. So, combining resin separation and Bioassays was not applicable to the research.2.The best concentration of typical disinfectants in this experiment were Sodium Hypochlorite:0.5mg/L,Chloramines:1mg/L,ChlorineDioxide:2mg/L,Ozone:20mg/L,Disinfecti on time:30S and Ultraviolet≥300J/m2. In the current concentrations,no deaths occurred in all embryos contaminated and biological toxicity slowing heartbeat, teratogenicity and inhibition of growth involved.Sodium Hypochlorite and Chloramines had analogous influence on embryos and toxicity of sodium was stronger. The main toxicity characteristic was a certain degree of teratogenicity and slowing heartbeat at72hours. Ozone got the greatest impact on heart rate ratio and teratogenicity. Embryos contaminated by water samples disinfected by Chlorine Dioxide had higher hatchability and lower teratogenic rate, and had minimal impact on heart rate ratio of fully developed zebra fish. Typical disinfectants ecological risk assessment results from high to low:Ozone>Sodium Hypochlorite>Chloramines>Chlorine Dioxide, Ultraviolet was used with chlorine disinfectant have got better disinfection than single disinfection method and combined with Ozone got the worst effect.3.The A/O Nitrogen removal process of B Sewage treatment plant could more reduce the embryos mortality rate than the conventional activated sludge process of A,and improved hatchability and heart rate,so B plant have Certain advantages and higher ecological security. |
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