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Oil removal - The treatment and removal of free and emulsified oils and greases is typically
accomplished by gravity separation, physical futration and/or notation. These treatment processes may be used
alone or in combination depending on the nature of the oils and greases to be treated and the strength of the
wastestream. In a scale pit where the water level and oil content vary considerably, saucer or rotating van
skimmers would be betler than endless rope or endless belt &kimmers.
Toxic metal pollutant removal- The treatment technologies for metals removal include those used for suspended
solids removal as well as chemical precipitation and magnetic filtration or separation.
High-gradient magnetic separation uses a matrix of fme ferromagnetic fibers, such as stainless steel wool, placed
in a strong magnetic field, to trap magnetic, micro-size particles from water. A bench-scale Kolm-Marston type
ofmagnetic separator has been found to reduce the suspended solids from blast furnace gas washer water to 5-20
mg/L at now rates of 18-200 gpm/fe. The 200 gpm/fe now rate is two orders oC magnitude higher than now
rates'for &edimentation and one order oC magnitude higher than deep bed fJlters. (McNallan, 1976)
Furnace exhaust gas cleaning systems include baghouses (a dry air pollution control system) and wet gas cleaning
systems such as venturi scrubbers, adjustable orifice &c:rubbers, separators, spray chambers, and hydroclones.
Though not used extensively because of the cosls of these treatment technologies, ion exchange, revr-rse osmosis,
and evaporation produce high quality water and may prove economical for small closed-loop recycle systems.
Further information on treatment technologies and pollution prevention practices can bc found in the papers
included in Attachment C or li~led in Attachments D and E.
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