
Mineral coatings on sand particles actually encourage microbial activity in the rapid sand filters that are used to treat groundwater for drinking, according to a paper. These findings resoundingly refute, for the first time, the conventional wisdom that the mineral deposits interfere with microbial colonization of the sand particles.
http://feeds.sciencedaily.com/~r/sciencedaily/~3/sGhH3AWOlHw/141010111739.htm