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1 引言 以地下水为水源的饮用水中,硝酸盐浓度是许多国家共同关注的问题。荷兰饮用水2/3源于地下水,其中有1/4硝酸盐问题突出,主要原因是农业大量采用氮肥,而对施肥加以限制和合理利用土地以降低硝酸盐浓度,尚未引起足够重视。与此相应的是饮用水水质根据1980年EC指令(EC directive)硝酸盐最大允许浓度(maximun admissible concentration MAC)为50～100mg NO_3~-,通常需控制在25mg/L以下。现就分离扬水法、硫黄——石灰石过滤法、离子交换法等三种去除硝酸盐浓度的方法,逐一进行分析。
1 INTRODUCTION Nitrate concentration in drinking water using groundwater as a source of water is a common concern in many countries. Two-thirds of the drinking water in the Netherlands is derived from groundwater. Among them, one-fourth of the nitrate problems are outstanding. The main reason is that agriculture uses a large amount of nitrogen fertilizer. However, restrictions on fertilization and the rational use of land to reduce nitrate concentration have not yet received sufficient attention. Corresponding to this, drinking water quality according to the EC directive of 1980, the maximun admissible concentration MAC 50 ~ 100mg NO_3 ~ -, usually need to control below 25mg/L. The three methods of removing nitrates, such as the separation method of water extraction, sulfur-limestone filtration, and ion exchange, are now being analyzed one by one.