连续流催化臭氧氧化降解富里酸及深度处理垃圾渗滤液的效能

Degradation of Fulvic Acid and Advanced Treatment of Landfill Leachate by Catalytic Ozonation in Continuous Flow Mode

研究了连续流条件下工艺参数对催化臭氧氧化降解富里酸(FA)的影响,并在此基础上考察了催化臭氧氧化深度处理实际垃圾渗滤液的效果。以FA为降解对象,Co-Mn-O为催化剂,研究了水力停留时间、催化剂投量、反应器高径比等因素对富里酸降解的影响,降解效果以TOC或CODCr去除效率表示。半连续流实验结果表明,催化臭氧化比单独臭氧化具有更高的富里酸矿化效率;连续不回流实验结果显示水力停留时间的延长、催化剂投加量的增加、反应器高径比的增大有助于富里酸降解效率的提高,综合考虑运行成本,三者适宜的工艺参数分别为58min、0.5g·L-1和6.5∶1。针对实际垃圾渗滤液尾水,经过去除氯离子和碱度的预处理后,连续回流催化臭氧氧化处理对其CODCr和色度具有良好的去除效果。

Firstly, UV-vis spectrum and TOC value of samples during catalytic ozonation of fulvic acid（FA）in semi-continuous mode were determined. The results suggested that with the progress of reaction, the characteristic peak in the ultraviolet region decreased rapidly and TOC removal efficiency gradually increased. It was demonstrated that unsaturated groups in the molecule of FA were degraded quickly into intermediates which was converted into carbon dioxide finally. The effect of technical parameters on catalytic ozonation of FA in continuous flow mode was studied. The main parameters included hydraulic retention time（HRT）, catalyst dosage, and Height to Diameter Ratio of reactor（H/D）. The results proved that the increase of HRT, catalyst dosage, and H/D of reactor were helpful to improve degradation efficiency of FA. Considering cost-effectiveness, the appropriate parameters were HRT 58 min, catalyst dosage 0.5 g·L^-1 , and H/D 6.5∶1 respectively. The test results in advanced treatment of landfill leachate by catalytic ozonation showed that the degradation efficiency of organic pollutants in landfill leachate was much high. After pretreatment to remove chloride ions and alkalinity in tailwater of landfill leachate, the chromaticity of the landfill leachate was completely removed and the removal efficiency of CODCr was nearly 80% by catalytic ozonation in continuous flow mode.