关于水污染的源头及处理和解决方法的一份英文课堂ppt
Reducing Water Pollution through Sewage Treatment Raw sewage reaching a municipal sewage treatment plant typically undergoes:– Primary sewage treatment: a physical process that uses screens and a grit tank to remove large floating objects and allows settling. – Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes.