The Treatment of Zefran®
Fiber Wastes
RONALD D. SADOW, Sanitary Engineer
Head, Utilities Department
The Dow Chemical Company
James River Division
Williamsburg, Virginia
INTRODUCTION
In about 1950, the discovery of a new acrylic alloy fiber took place in the
laboratories of The Dow Chemical Company. In 1957 ground was broken near
Williamsburg, Virginia, for the construction of research and production facilities for the commercial entrance of Zefran acrylic fiber --a new concept in
the textile field (1).
Virginia was selected mainly because of its proximity to the large textile
mills and markets of the southeast, along with the nearness to navigable waters. The now completed plant is on the James River just southeast of Williamsburg. One of the finest oyster seed areas in the world is located in the
James just adjacent to the company's property. To avoid even the remotest
possibility of toxic pollution in these waters, the'fiber wastes generated had
to be effectively treated.
Zefran synthetic fiber is produced from acrylonitrile through a series of
steps involving polymer preparation and spinning. Besides the small amount
of domestic sewage that would be present, the main industrial wastes to be
handled are acrylonitrile (a vinyl cyanide), and a heavy metal-zinc. There
would also be a conglomeration of laboratory wastes from the textile research
facilities to be located on the site, along with minor losses from the powerhouse.
THE PROBLEM
Because an organic molecule was available for possible degradation, it was
reasoned that a process utilizing biological oxidation should be used. As
soon as the decision was made to produce Zefran, preliminary studies were
started by the company's Midland Division on the various aspects of the products' wastes.
Bio-assays dealing with the effects of zinc ion on shiners in Lake Huron
water were initiated (2). The National Academy of Sciences in Philadelphia,
Pa. , undertook a lengthy study of the biota in the James River above and below the location of the projected plant's outfall to establish an ecological base
line (3).
It was during this period that a revolutionary type of trickling filter media
was being developed by The Dow Chemical Company. This packing,called
Dowpac®, consists of individual sheets (either saran or polystyrene) corrugated
in two directions and field assembled into self-supporting packing modules.
Because of this media's void space (94 per cent), large surface area, and
lightweight (3.6 - 6.0 lbs/cu ft) structural properties, improved biological
performance can be expected with smaller volumes of packing (4).
® Registered trademark of The Dow Chemical Company.
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