臭氧/活性炭协同作用去除二级出水中DON

为探讨臭氧氧化和活性炭吸附对城市污水厂二级出水中溶解性有机氮(DON)的去除机制,首先测定二级出水DON、溶解性有机炭(DOC)、UV254、pH值等指标.接着通过臭氧氧化试验和活性炭吸附试验来考察二级出水中DON、DOC和UV254变化,以及DON分子量分布和DON亲疏水性变化,并应用三维荧光光谱对二级出水中DON变化进行表征.结果表明,当臭氧投加量为8mg/L,DON的去除率大约为33.9%,DOC和UV254去除率约21.2%、66.7%;当活性炭投加量为2.0g/L,DON、DOC和UV254的去除率大约为43.4%、27.6%、92.2%;臭氧氧化和活性炭吸附组合试验时,对DON的去除率大约为83.3%和81.5%;臭氧氧化提高小分子量( 20kDa)的DON所占比例;活性炭吸附降低小分子量( 20kDa)DON所占比例为;臭氧氧化和活性炭吸附都提高亲水性DON所占比例,而降低疏水性和过渡性DON所占比例;三维荧光光谱证实,二级出水中DON变化与3个主要峰有关,分别代表物质为色氨酸类蛋白质、芳香族类蛋白质和富里酸类物质.

Removal of dissolved organic nitrogen in the secondary effluent by integrated ozone/activated carbon

The mechanism of DON removal in the secondary effluent by ozonation and adsorption was investigated in this study. The water quality parameters, such as DON, DOC, NH4+-N, UV254 and pH etc, were determined. The variation in DON, DOC andUV254 in ozonation and adsorption tests measured, and the molecular weight distribution, hydrophilicity and hydrophobicity of the DON were then analyzed. The changes of DON in the secondary effluent were characterized using three-dimensional fluorescence spectroscopy. The results showed the removal of DON, DOC andUV254 were about 33.9%, 21.2% and 66.7%, respectively, at ozonation test and the dosage of ozone was 8mg/L. The removal of DON, DOC and UV254 were about 43.4%, 27.6% and 92.2% at the activated carbon dosage of 2.0g/L. By the combination of ozonation and adsorption the removal of DON was approximately 83.3% and 81.5%. Ozonation and acitivated carbon adsorption had opposite effects on the molecular distribution of DON. The proportions of smaller (20 000) ones were decreased by the former and increased by the later. Both treatment could increased the proportion of hydrophilic DON, and decreased them of hydrophobic and transitional DON. 3DEEM revealed that the variation of DON in ozonation and adsorption tests depended intimately on tryptophan protein-like and aromatic protein-like substances, and fulvic acid-like respectively.