城市下水道是保障居民洁净生活的重要设施之一,但却让市政工人非常烦恼,因为处理下水道的淤泥是一件令人头疼的事情。环保部门也为这些淤泥而烦恼,而下水道淤泥是城市河道的污染源之一。最 Urban sewers are one of the important facilities for protecting the clean living of the residents, but they are very annoying to municipal workers because dealing with the silt of the sewers is a headache. Environmental protection departments also worry about these silt, and sewer silt is one of the pollution sources of urban rivers. most