| At present,there are unequal amounts of difficult biodegradable organic matter in the effluent of conventional wastewater plants,which has harmful effects on human body and other organisms,and the biological method has very limited effect on the removal of organic wastewater with complex composition and stable structure.Advanced oxidation method has the advantages of improving the biochemical properties of water bodies and no secondary pollution,but there are disadvantages such as high energy consumption and high cost when advanced oxidation method is used alone.In this thesis,the biodegradation performance of organic matter in domestic wastewater biological treatment effluent was studied by biological oxidation,oxidation and their combined processes respectively,and the removal effect of difficult biodegradable organic matter was investigated by selecting aeration biofilter,Fenton oxidation and Fenton oxidation pre-treatment-aeration biofilter post-treatment processes according to the advantages,disadvantages and feasibility of various methods,and the following conclusions were drawn.（1）aeration biofilter using school secondary sedimentation tank effluent as the raw water,PET resin as filler,start the process in the air to water ratio of 3:1,flow rate of 1.0 m/h,hydraulic retention time of 21min,water temperature of 10℃～23℃,the inlet water p H 7.2～7.6 conditions,the first natural hanging film,over a period of 35 days,hanging film effect is very little,and then use inoculation hanging film,over a period of 50 After that,the film was successfully started by inoculation for 50 days.（2）Through studying the effect of different air-water ratio and flow rate of aeration biofiltration on the removal of organic matter in water,it was found that both of them had significant effects on the degradation rate and degree of differentiation of organic matter.In the range of hydraulic load 0.5 m3/（m2·h）-1.5 m3/（m2·h）,the organic matter in water was basically divided into four parts:easy biodegradable organic matter,biodegradable organic matter,difficult biodegradable organic matter and non-biodegradable organic matter,and showed the characteristics of the greater the hydraulic load,the finer the degree of differentiation and the longer the time to reach the end point.（3）A four-factor,four-level orthogonal experiment was conducted on the biological effluent of the aeration biofilter treated with Fenton reagent method,and the results showed that the four influencing factors on the COD removal effect were in the following order:H2O2 dosage>p H>reaction time>Fe SO4-7H2O dosage,and the best reaction conditions of the orthogonal experiment were:H2O2:COD=2,p H=3,Fe2+:H2O2=1.0,t=60 min.Fe2+:H2O2=1.0,t=60min,when the COD removal rate is 54.44%.（4）The optimum parameters of the reaction determined by the Fenton reaction single-factor test were H2O2:COD=1:1,p H=3,Fe2+:H2O2=1:1,t=4h,room temperature,under which the COD concentration was reduced to 3.6mg/L and the removal rate was 80.00%.（5）Using the Fenton oxidation pretreatment+aeration biofilter post-treatment process,the effects of two factors,different H2O2 and COD equivalent ratios and reaction time in the Fenton reaction,on the removal effect of Fenton oxidation and biological oxidation on COD were investigated and found that this process relied mainly on Fenton oxidation for the removal of organic matter from low concentration domestic wastewater,and the role of aeration biofilter was not obvious. |
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