A Statistical Study of Five Years Operation
of the West Virginia Pulp and Paper
Company's Waste Treatment Plant
OLIVER B. BURNS, Jr., Pollution Abatement Supervisor
West Virginia Pulp and Paper
Covington, Virginia
W. WESLEY ECKENFELDER, Jr., President
Hydroscience, Inc.
Englewood Cliffs, New Jersey
INTRODUCTION
The Bleached Board Division ofthe West Virginia Pulp and Paper Company is
headquartered in Covington, Virginia. The Covington Mill produces primarily
high quality bleached board from kraft pulp and corrugating medium from neutral
sulfite semi-chemical pulp. The total paper and board production is about 1, 000
T/D.
An integral part of a concentrated effort to improve stream conditions below
the mill led to the construction of an activated sludge waste treatment plant in
1955, only after pollution reduction at the source had reached the point of diminishing returns. As operating experience with the plant was gained and improvements added, it was possible to treat greater portions ofthe mill waste. Figure 1
illustrates the increasing BOD loadings the plant has accepted since startup and
also demonstrates the ability of the system to effectively treat the wastes.
The original plant consisted of one 100 ft diameter primary clarifier for the
sedimentation of wastes with high suspended solids content ana activated sludge
treatment for the settled wastes and a major portion of the low solids Bleach Plant
flow which entered the secondary system directly. The paper machine wastes,
some of the Bleach Plant flow, and a few miscellaneous wastes did not receive
treatment initially. In 1959, in order to increase the plant's capacity and efficiency, diffused air aeration units were replaced by dual rotor turbine aerators and
a second 100 ft diameter primary clarifier and an equalization tank were added to
the facilities. Immediately after the expansion, additional wastes from the paper
machines and more miscellaneous flows were accepted for treatment. All wastes
were then mixed in the new equalization tank and the total flow equally split be -
tween the two primary clarifiers.
BOD REMOVAL
The removal of BOD from simple substrate has been observed to exhibit zero
or first order kinetics at low concentrations of BOD. In complex wastes such as
those from pulp and paper mills, however, the constituents are subject to varying
reaction rates. This results in a decreasing overall rate of removal of the various
components. The overall rate of BOD removal can, therefore, be defined by a
retardant type reaction. This form of equation was employed to define BOD reduction through the aeration tanks. The plot to determine the rate coefficients for
numerous runs in which samples were withdrawn at the end of each day in the
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