Which filtering material was better at filtering the pollutant from the water

Question

Sand

Rocks

Sand over rocks

Soil layered over sand

Answer 1

It depends on the specific pollutant being filtered. In general, soil layered over sand is likely to be the most effective at filtering a wide range of contaminants from water, as it can trap both particulate matter and certain dissolved pollutants. Sand and rocks alone may not be as effective at removing pollutants, although they can still provide some filtration benefits.