Moreover, due to the property that the amount of the wastewater of the urban areas is relatively fixed, reclaimed wastewater bas been utilized as one of the major water sources of many countries.

• 而在都市地区更因其废污水具有水量固定的特性，因此许多国家的都市地区，将其废污水回收再利用作为都市用水的水源之一。