Activity for Frank‭

Type	On...	Excerpt	Status	Date
Question	—	How do slow sand filters work and are there any alternatives? Slight Introduction: A slow sand filter is a filter used to purify water. The original design is composed of a layer of gravel, then a layer of fine sand. Sometimes, however, there is an extra layer of bacteria on the top doing most of the purification. This layer of bacteria is called the Schm... (more)	—	over 7 years ago