PROCESS DESCRIPTION - CONTINUED
The SSP takes a side stream of unstabilized water and doses it
with carbon dioxide (De Souza et al., 2000). The acidified CO2-dosed
side-stream then contacts a limestone bed, which will dissolve
a considerable amount of CaCO3, increasing
alkalinity and calcium concentration in the water. Much of the
remaining CO2 is recovered by stripping
with air and reused in the process whereas the stabilized side-stream
blends with the main stream for full stabilization.
The Simplified SSP is similar to the SSP but excludes CO2
recovery. In this process, there are two options that can be carried
out after the acidified CO2-dosed side-stream
contacts with a limestone bed: (1) Strip CO2
from the sidestream with no recovery, or (2) blend the sidestream
and mainstream without stripping (De Souza et al., 2000).
The Spraystab I is intended for small groundwater systems that
need to remove iron or manganese. It combines aeration, limestone
stabilization and filtration in one tank (Mackintosh, De Souza
and De Villiers, 2003). The raw groundwater is first aerated to
strip excess carbon dioxide from water and dissolve oxygen in
the water to be stabilized. Finally, the water flows through a
dual media filter (top layer of hydro-anthracite and lower layer
of filter sand). In the filter, the limestone fines and other
insoluble matter such as iron and manganese flocs are removed.
The Spraystab II is intended for small groundwater systems that
do not need to remove iron or manganese.
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