mean annual discharge

例句：

1. 1. The river's mean annual discharge is 10 million cubic meters.
   这条河流的年平均流量是1000万立方米。
2. 2. The city's wastewater treatment plant processes an average annual discharge of 500,000 tons.
   该城市的污水处理厂每年处理废水量为50万吨。
3. 3. The company's mean annual discharge of pollutants is below the national standard.
   该公司的年均污染物排放量低于国家标准。