| At present, thetreatment of refractory organic waste waterin sewage treatment industry isstill a big challenge at home and abroad. The so-called ‘refractory’ here refers that thebiodegradability of this kind of waste water is low and it is quite difficult to biodegrade.Generally speaking, petrochemical waste waterand the waste water of fluorescent agent arecomplex in composition and they have the characteristics of strong toxicity, highconcentration and environmental pollution so that it is hard todegrade them by biologicalmethods. Thus, in this thesis, the author attempts to use these two kinds of refractory organicwaste water mentioned aboveto do research respectively.As forthe petrochemical waste water,firstly, the author measured its COD, and analyzedit with infrared spectrum, and then, by single factor test,the author determined themicrowavepower, irradiation time, pH value, dosage of activated carbon, the consumption of oxidant andcatalyst respectively to get the bestresults. Finally, it’s the composite test, through observingthe changes of various factors in different combinations and conditions to determine the besteffects.Under microwave,50ml waste water, which was diluted for20times, was radiated bymedium microwave for five minutes, and the author added0.1g CuO,0.1g activated carbonand0.5ml3％H2O2, and then finally get the COD is73mg/L, the rate of decrease was80%. Inaddition, during the process of experiment, it found that the wastewater under alkalineconditions would settle with metalion. For this phenomenon, in the further test,1.4FeSO4were added to50ml waste water, and under alkaline conditions, it was radiated by mediummicrowave for two minutes. The result shows that the COD decreased from7380mg/L to608mg/L, the rate of decreasewas92%. The result proves that under microwave, the subsidenceeffect is better than the effect of catalytic oxidation.As for the waste water of fluorescent agent, through analyzing its characteristics and thedifficult reasons, the author determined microwave radiation treatment scheme. When thepower is600W, irradiation time is9minutes, the pH value is4, at most, the removal rate ofCOD is only38.8%. Then, the author added acid to settle the waste water, and when the valueof pH was adjusted between1and2, the COD removal rate was above52%.So it finds thatunder the condition of aid sinking, microwave works better.Based on this, in the further study,microwave method,hydrogen peroxide-microwave method,activated carbon-microwavemethod,copper oxide-microwave method and load copper oxide-microwave method were used to study the effect of treating waste watercomparatively,and meanwhile, to explore theinfluence ofthe microwave power, irradiation time, pH value and dosage on the treatmenteffect and its mechanism of action.The experimental results indicatethat when the radiationpower is600W, irradiation time is9minutes, pH value is2and hydrogen peroxide, whosemass fraction is30%, is0.3ml and the load CuO, whose mass fraction is1%, is0.8gram, theCOD removal rate in waste waterof fluorescent agent reaches81.23%. Although the effect isnot very ideal, it shows that under the condition of microwave radiation, the effect ofcatalytic oxidation of fluorescent agent’s waste water is better.In order to apply this technology to industrial production and improve the feasibilityof the treatment of refractory organic wastewater,so in this study, the author would like topurify inacidic condition to subside most difficult biodegradable fluorescent agent,and usedmicrowave method to make its COD reduce to2600mg/L. Then the author used Fentonoxidation and the method of adding lime in that thestrong oxidability of Fenton and the effectof flocculent settling would improve the biodegradability of waste watertoreduce COD toabout700to800mg/L. At last,the available biological methods were used to reduce COD ofthe waste waterto75mg/L and make the overall removal rate reach98.63%. All in all, the costof this treatment is low, while, the effect of purification is remarkable. |
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