The slag-only Vertical Flow Pond, which we have developed, is a passive treatment
component capable of removing large concentrations of metals, especially manganese,
from water to extremely low concentrations while neutralizing acidity and producing
alkalinity. An improvement to this design is the Hybrid Flow Pond (HFP), which
is a passive treatment system component that consists of an open, pond-like structure
utilizing a horizontal operational flow path (or a vertical flow path if desired)
with a vertical flush flow path. By creating flushing flow paths generally perpendicular
to operational flow paths, the development of preferential flow paths that encourage
short circuiting can be prevented. Additional head can be generated prior to flushing
by adjusting the water level in the pond. Although any treatment media can be used
with this system, the use of basic steel slag is particularly useful in the removal
of metals, especially manganese from aqueous solutions. These metals are either
retained within the pond or flushed from the pond into a separate pond to accumulate
in order to recover them at a later point in time.
