Appeal No. 1997-4285 Page 9
Application No. 08/420,852
The waste stream is first held in one of two holding tanks 14,
16. Then, the waste stream is transferred to a third holding
tank 18 where its pH is adjusted to approximately 5.0, as
shown at 20. By way of example, pH adjustment is accomplished
by adding either lime or hydrosulfuric acid to make the waste
stream more basic or acidic,
respectively. After pH adjustment, ferrous sulfate and
hydrogen peroxide are continuously added to the waste stream
in a mixer reactor 22 as shown at 24, 26. The ferrous sulfate
is first added in the reactor 22 in an amount based on the
initial phenol concentration in the waste stream. The
hydrogen peroxide is added into the mixer reactor 22 after the
ferrous sulfate. The iron in the ferrous sulfate catalyzes
the hydrogen peroxide causing it to oxidize the phenol in the
waste stream. The pH and the amount of unoxidized hydrogen
peroxide is sensed at 28 and 30, respectively, shortly after
the waste stream leaves the mixer reactor 22. Oxidation of
the hydrogen peroxide can be sensed by measuring its oxidation
reduction potential (ORP), a process which would be well
familiar to a person skilled in the art.
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