Design Of Novel UV-Fenton Reactor And Study On Its Optimization Of Semi-industrial Experimental Conditions

As a most promising advanced oxidation technology, Photo-Fenton process has become the preferred method to treat the refractory organic wastewater for its advantages of wide application range, high degradation efficiency and rare secondary pollution, In this article, a novel UV-Fenton reactor was designed and produced, then the treatment effects of a low concentration of refractory organic wastewater (orange Ⅱ solution) and a high concentration of refractory organic wastewater (landfill leachate) employing the reactor were studied. The main research results are as follows:(1) Based on UV-Fenton system degradation mechanism of organic matters, the design concepts of a novel UV-Fenton reactor were proposed. A semi-industrial scale UV-Fenton device was designed and produced based on the UV-Fenton reactor.(2) The reactor performed high efficiency for the Orange Ⅱ solution treatment, within 120 min the degradation rate and mineralization rate of Orange Ⅱ could reach to 97.55% and 93.12%. The degradation proeess accords with first order reaction kinetics equation. The main factors such as H2O2 dosage, H2O2/Fe2+ molar ratio, aeration rate, UV wavelength and UV lamp power that affect the treatment effect are discussed.Among these factors, H2O2 dosage and aeration rate showed the greatest impact on the results, and they were positively correlated with the treatment effect, while the affects of other conditions were rather small. This UV-Fenton reactor may not open the UV lamp when dealing with low concentrations of refractory organic wastewater.(3) The reactor performed high efficiency for the landfill leachate treatment, the result showed that under the condition of a certain amount of H2O2 dosage, the COD removal efficiency increased with increasing addition frequency. A two factors and four levels complete experiment was conducted to study the impact H2O2 dosage and aeration rate on COD removal efficiency, then the complete experiment result was analyzed. The result showed that COD removal efficiency rose with the increasing of H2O2 dosage while the corresponding increasement of the COD removal efficiency reduced gradually. COD removal efficiency began to decline slowly when H2O2 dosage reached up to 85 mmol/L. When the H2O2 dosage remained at a high level, COD removal efficiency even declined with increasing the aeration rate. While H2O2 dosage was relatively small, improving the aeration rate could enhance the COD removal efficiency. Therefore the oxygen can partially substitute hydrogen peroxide as the oxidant to reduce the hydrogen peroxide dosage under this condition, by which the economic treatment could be achieved.Under the condition that the UV-Fenton reactor can treat the landfill leachate to meet the emission standard, economic cost-optimal experimental conditions are:H2O2 dosage 70 mmol/L and aeration rate 11L/min. Within 120 min the effluent COD is 95 mg/L, COD removal efficiency is 86.58%, and color removal effect is obvious. The novel UV-Fenton reactor designed in this article has the potential to be put into industrial applications.