PERFORMANCE OF A BIOPHYSICAL TREATMENT PROCESS
ON A HIGH-STRENGTH INDUSTRIAL WASTE
Gerhard Frohlich, Engineer
Hoffman-La Roche, Inc.
Nutley, New Jersey 07110
R. B. Ely, Manager
T. J. Vollstedt, Development Engineer
Zimpro, Inc.
Rothschild, Wisconsin 54474
INTRODUCTION
The addition of fairly high levels of powdered activated carbon to an activated sludge
system produces some rather remarkable results.   It appears that much more is involved
than just simultaneous biological oxidation and physical adsorption.   When carried out
together, the two operations have a synergistic effect [1-7].   The biomass and activated
carbon work together in a manner to remove both components that are biologically
degradable and those that are adsorbable.   Advantages claimed for the process include:
a. It has the ability to carry active biomass at levels two to three times higher than activated sludge and thus reduce aeration basin size and hydraulic detention time.   It is
the weighting effect of the carbon that makes this possible.
b. The massive amounts of carbon present in the aeration basin tend to serve as an
"organic sink" for shock loads of toxic or refractory materials.
c   Oxygen transfer is improved-probably as the result of adsorption-desorption of gas
from the activated carbon
d. A larger portion of marginally degradable organics are biologically assimilated due
to the long sludge residence time.   This enables the carbon to carry a higher load of
truly refractory material.
e. Nitrification is easily achieved with the long sludge residence time.
f. Odor, color and foaming problems are reduced.
In late 1974, Zimpro Inc. of Rothschild, Wisconsin, was engaged by Hoffmann-La Rocne
of Nutley, New Jersey, to conduct a treatability and design study employing biophysical
treatment technology.   The study provided an opportunity to test the economy and effectiveness of biophysical treatment with powdered activated carbon in yet another
application.
Hoffmann-La Roche is a producer of pharmaceuticals and fine organic chemicals.   A
major expansion in intermediates manufacturing capacity was proposed to go in as a
"grass roots" facility at Freeport, Texas.   Some of the wastewater that was expected to
come from that facility was known to be difficult to treat biologically and the anticipate
high flow and dissolved solids contents eliminated incineration from consideration.
Laboratory-scale tests indicated that certain individual streams could best be handled
by a pretreatment of wet air oxidation and then composited with the remaining streams
for subsequent biological treatment.   Strict effluent requirements meant that a thorough
biological oxidation would likely have to be followed by carbon adsorption.   The possible
effect of wide swings in the raw waste composition and load resulting from production
changes and process upsets on the biological treatment system encouraged Hoffmann-
La Roche to further investigate biophysical treatment because of its operational stability
STUDY OBJECTIVES
The full-scale process contemplated activated sludge treatment of the composite w****)£,!.
However, bench-scale laboratory studies indicated that the effluent produced in this m
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