Transcript SSF Functions - Purdue College of Engineering

Slow Sand Filter Basics
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The sand provides a large surface area for “good”
micro-organisms to attach and be retained in the
filter (high biomass retention time).
Influent dissolved organic matter (DOM) is removed
by microbial mineralization (CO2 and H2O) by the
good bacteria (reducing color and odor).
Influent particles are removed by attachment to
(collection on) the large surface area (reducing
turbidity).
The top Schmutzdecke layer enhances both filtration
and mineralization of particles and DOM.
Slow sand filters can be operated as continuous
flow or batch reactors.
The long hydraulic retention time (8 hrs) allows for
complete mineralization, and reduces biomass
growth that would clog the filter.