Interactions between microbial activity and distribution and mineral coatings on sand grains from rapid sand filters treating groundwater

Rapid sand filtration is a traditional and widespread technology for drinking water purification which combines biological, chemical and physical processes together. Granular media, especially sand, is a common filter material that allows several oxidized compounds to accumulate on its surface. Preliminarily, we detected a strong relation between the amount of DNA and mineral coating mass.

We hypothesized that the accumulated mineral coatings have a positive effect on amount of bacterial biomass, its spatial distribution and substrate removal rates. In this study, we combined molecular, microscopic, physico-chemical and biokinetic techniques to determine the interaction between attached bacteria and attached minerals in rapid sand filters as well as the causality of the relation.

Strong pairwise correlations revealed the strong relation between mineral physical properties and bacterial activity and abundance indicated that attached minerals are an important factor controlling bacterial colonization, growth, distribution and substrate utilization in these systems.