The Use of Reverse Osmosis in Treatment of
Weak Semichemical Wastewaters
DAVID C. MORRIS, Assistant Technical Director
WILLIAM R. NELSON, Director of Corporate Development
GERALD O. WALRAVEN, Technical Director
Green Bay Packaging, Inc.
Green Bay, Wisconsin
INTRODUCTION
Green Bay Packaging Inc. operates a neutral sulfite semi-chemical (NSSC) pulp
and paperboard mill on the Fox River at Green Bay, Wisconsin. In 1968, a report was
made t the 23rd Annual Purdue Industrial Waste Conference on the possible
application of reverse osmosis in a program of pollution abatement. This was
presented under the title, "A Role for Reverse Osmosis in a NSSC Pulp and
Paperboard Mill".
Investigation of reverse osmosis technology has continued at Green Bay
Packaging, and it included the operation of pilot equipment in 1968 through 1970;
this effort culminated in a commitment to incorporate reverse osmosis in the mill
process as a production tool. The present status of our investigation and the planned
integration of reverse osmosis into the overall process will be described.
BACKGROUND
The pulp mill operations are typical of the NSSC process, and these are shown
in Figure 1. This operation produces about 210 tons of pulp per day. The reaction
products of pulping result in the production of 200,000 lbs of associated dissolved
solids. Approximately 70 percent of these solids are separated from the pulp at the
digester and by screw presses; these wastes are in a strong form (about 12.5 percent
dissolved solids). The pressed cooked wood chips are then mechanically refined, a
process which results in dispersing both fibers and remaining entrapped dissolved
solids in large volumes of water.
The paper mill operations are shown in Figure 2. About 60 tons of corrugated
waste clippings are dispersed in recycled water and blended with the virgin pulp.
Following further processing and dilution, the fibers are formed into the paperboard
web; and the majority of the drained water is again recycled.
A FluoSolids combustion process, developed by Dorr-Oliver, has been in use at
Green Bay since 1966 for the ultimate destruction of strong wastes. Preliminary trials
had shown that this combustion plant could be modified to provide additional
capacity if the remaining weak wastes could be separated and concentrated and then
added to the strong wastes regularly separated in the pulp mill. The 1968 report
described conditions existing at that time, and a rationale was presented for the
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