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西安市为我国西北地区最大的工业城市之一。由于“三废”的大量排放,给环境带来了严重的污染。每天排放的城市废水达数十万吨(其中70％左右是工业废水),这些废水未经处理,含有多种有害物质。除一部分排入附近河道外,主要通过下水系统,输送到北郊进行污水灌溉,污灌面积27万亩。城市废水在排放和灌溉过程中,不断渗入地下,成为地下水污染的主要污染源。
Xi’an is one of the largest industrial cities in Northwest China. Due to the huge emission of “three wastes”, it has brought serious pollution to the environment. There are hundreds of thousands of tons of municipal wastewater discharged daily (about 70% of which is industrial wastewater), which are untreated and contain many kinds of harmful substances. In addition to part of the discharge into the nearby river, mainly through the sewer system, transported to the northern suburbs for sewage irrigation, sewage irrigation area of 27 mu. Urban wastewater continues to seep into the underground during discharge and irrigation and become the main source of pollution of groundwater.