Appeal No. 1997-4285 Page 10
Application No. 08/420,852
Pahmeier teaches that if the hydrogen peroxide is not
sufficiently oxidized, it may be recycled as shown at 32 to
the third holding tank 18. Otherwise, it is held in a holding
tank 34 for approximately one hour. This ensures a maximum
amount of phenol will be oxidized. Then, more ferrous sulfate
may be added to the waste stream at 36 by means of a mixer 37,
to remove any residual hydrogen peroxide that remains after
the one hour holding period. If no residual hydrogen peroxide
is present, then no ferrous sulfate is added at this
particular point. The amount of residual hydrogen peroxide is
sensed at 38 by ORP measurements. The waste stream is then
transferred to a clarifier 40. In the clarifier, the pH of
the waste stream is again adjusted by using lime to a pH
ranging between 8.5 to 9.5.
This pH adjustment is followed by adding a polymer, which
causes flocculation in the waste stream and produces sludge.
The sludge, which contains heavy metals, is removed from the
clarifier as shown at 42, and is thickened in a sludge tank
44. The remaining liquid effluent from the clarifier 40 is
transferred as shown at 46 to one of two holding tanks 48, 50.
Sludge in the tank 44 is thickened and transferred to a filter
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