Measurements of dissolved organic nitrogen (DON) in water samples with nanofiltration pretreatment.
Measurements of dissolved organic nitrogen (DON) in water samples with nanofiltration pretreatment.
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DOI：
10.1016/j.watres.2010.06.034
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发表时间：
2010-10
期刊：
影响因子：
12.8
通讯作者：
Bin Xu;Da-Peng Li;Wei Li;Shengji Xia;Yi-Li Lin;Chen-yan Hu;Cao-Jie Zhang;N. Gao
中科院分区：
文献类型：
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作者：
Bin Xu;Da-Peng Li;Wei Li;Shengji Xia;Yi-Li Lin;Chen-yan Hu;Cao-Jie Zhang;N. Gao
对于溶解无机氮（DIN，包括亚硝酸盐、硝酸盐和氨）与总溶解氮（TDN）之比较高的水样，由于独立测量的氮种（TDN和DIN）的累积分析误差，使用传统方法测量溶解有机氮（DON）是不准确的。在本研究中，我们提出了一种纳滤（NF）预处理方法，通过选择性地浓缩DON，同时通过水样中的DIN物种，以降低DIN/TDN比率，从而提高DON测量的准确性和精密度。测试了三种商用NF膜（NF90、NF270和HL）。杨树普饮用水处理厂出水对HL、NF90、NF270的截除率分别为12%、31%、8%、26%、28%、23%、77%、78%、82%、83%、87%、88% uv254。NF270表现出最好的性能，因为它具有高DIN渗透率和DON保留率（约80%）。NF270可以将DIN/TDN比值从1左右降低到小于0.6 mg N/mg N，并在优化的操作参数下获得了令人满意的合成水样中DOC回收率和DON测量值。与现有的透析预处理方法相比，NF预处理方法对含水样品的DON测量表现出类似的改进性能，并且可以节省至少20小时的操作时间和大量的去离子水，这对参与DON分析的实验室是有益的。研究了石酒阳水厂（YDWTP）和石酒阳水厂（SDWTP）不同处理工艺的出水DON浓度。结果表明，在两个处理厂的每个水处理工艺后，经纳滤预处理的DON和DOC均逐渐降低。SDWTP的生物预处理、澄清、砂滤、臭氧- bac工艺对DON的去除率为0.37 ~ 0.11 mg N L−1，高于YDWTP的预臭氧化、澄清、砂滤工艺对DON的去除率为0.18 ~ 0.11 mg N L−1。
Dissolved organic nitrogen (DON) measurements for water samples with a high dissolved inorganic nitrogen (DIN, including nitrite, nitrate and ammonia) to total dissolved nitrogen (TDN) ratio using traditional methods are inaccurate due to the cumulative analytical errors of independently measured nitrogen species (TDN and DIN). In this study, we present a nanofiltration (NF) pretreatment to increase the accuracy and precision of DON measurements by selectively concentrating DON while passing through DIN species in water samples to reduce the DIN/TDN ratio. Three commercial NF membranes (NF90, NF270 and HL) were tested. The rejection efficiency of finished water from the Yangshupu drinking water treatment plant (YDWTP) is 12%, 31%, 8% of nitrate, 26%, 28%, 23% of ammonia, 77%, 78%, 82% of DOC (dissolved organic carbon), and 83%, 87% 88% of UV254for HL, NF90 and NF270, respectively. NF270 showed the best performance due to its high DIN permeability and DON retention (∼80%). NF270 can lower the DIN/TDN ratio from around 1 to less than 0.6 mg N/mg N, and satisfactory DOC recoveries as well as DON measurements in synthetic water samples were obtained using optimized operating parameters. Compared to the available dialysis pretreatment method, the NF pretreatment method shows a similar improved performance for DON measurement for aqueous samples and can save at least 20 h of operating time and a large volume of deionized water, which is beneficial for laboratories involved in DON analysis. DON concentration in the effluent of different treatment processes at the YDWTP and the SDWTP (Shijiuyang DWTP) in China were investigated with and without NF pretreatment; the results showed that DON with NF pretreatment and DOC both gradually decreased after each water treatment process at both treatment plants. The advanced water treatment line, including biological pretreatment, clarification, sand filtration, ozone-BAC processes at the SDWTP showed greater efficiency of DON removal from 0.37 to 0.11 mg N L−1than that at the YDWTP, including pre-ozonation, clarification and sand filtration processes from 0.18 to 0.11 mg N L−1.