sand filtering

例句：

1. 1. The sand filter is used to remove impurities from the water before it reaches the final treatment stage.
   沙子过滤器用于在水到达最终处理阶段之前去除杂质。
2. 2. During the sand filtration process, the water is passed through a series of screens to remove larger particles.
   在沙过滤过程中，水通过一系列筛网以去除较大的颗粒。
3. 3. The sand filtration system is designed to ensure that only clean water is released into theenvironment.
   沙过滤系统旨在确保只有清洁的水被释放到环境中。