Darbi A, Viraraghavan T, Butler R, Corkal D
Faculty of Engineering, University of Regina, Regina, Saskatchewan, Canada.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2003 Sep;38(9):1703-15. doi: 10.1081/ese-120022873.
Due to the extensive application of artificial nitrogen-based fertilizers and animal manure on land, many water agencies face problems of increasing concentrations of nitrate in groundwater. The contamination of groundwater by nitrate may pose a significant public health problem. The threat of methemoglobinemia is well documented and reflected in the US drinking water standard of 10 mg/L as nitrate-nitrogen. Approximately 45% of Saskatchewan's population use groundwater for drinking purposes, out of which, approximately 23% (230,000) are rural residents. The water used is made available from over 48,000 privately owned wells in regions where there is an extensive application of chemical fertilizers. Biological denitrification, ion exchange, and reverse osmosis (RO) processes were selected for a field study. Field studies were conducted on these processes. The sulfur/limestone autotrophic denitrification (SLAD) process was selected to achieve biological removal of nitrate from groundwater. The feasibility of the system was evaluated under anaerobic conditions. An ion exchange study was conducted using Ionac A554 which is a strong anion exchange resin. In the case of groundwater containing low sulfate concentrations, A554 offered high nitrate removal. However, the disposal of regenerant brine can be a problem. A reverse osmosis unit with Filmtec membrane elements (FT30-Element Family) was used in the study on nitrate removal. The unit effluent average nitrate concentration was less than the maximum allowable concentration.
由于人工合成氮肥和动物粪便在土地上的广泛施用，许多供水机构面临着地下水中硝酸盐浓度不断上升的问题。硝酸盐对地下水的污染可能会引发重大的公共卫生问题。高铁血红蛋白血症的威胁已有充分记录，并反映在美国饮用水标准中硝酸盐氮含量为10毫克/升这一规定上。萨斯喀彻温省约45%的人口以地下水作为饮用水源，其中约23%（23万）为农村居民。所使用的水取自化肥大量施用地区的48000多口私人水井。选择了生物反硝化、离子交换和反渗透（RO）工艺进行实地研究。对这些工艺进行了实地研究。选择了硫/石灰石自养反硝化（SLAD）工艺来实现从地下水中生物去除硝酸盐。在厌氧条件下评估了该系统的可行性。使用强阴离子交换树脂Ionac A554进行了离子交换研究。对于硫酸盐浓度较低的地下水，A554对硝酸盐的去除效果较好。然而，再生盐水的处置可能会成为一个问题。在硝酸盐去除研究中使用了配备Filmtec膜元件（FT30元件系列）的反渗透装置。该装置的出水平均硝酸盐浓度低于最大允许浓度。
