Diatomite Filtration in a Closed
Water System
FRANCIS B. HUTTO, JR., Section Chief
Johns-Manville Research and Engineering Center
Manville, New Jersey
INTRODUCTION
With the nation's growing concern over water pollution all industrial users of
water must ultimately face the decision to clean up or close up. Of the two, it
is Johns-Manville *s philosophy that closing up is usually the better course of action.
In the first alternative there is faced the guaranteed certainty that tomorrow's stream discharge standards wont be the same as those today. The salient
point in the clean streams bill was that "regardless of the standards set, water
discharged to a stream should be of no worse quality than that already in the
stream. " It follows then that stream quality should and shall improve. This in
itself is fine but it is a specter which hangs over the head of every project designed to process industrial waste for stream discharge. We must always guess
how much the stream will improve and how quickly so that X years from the
time of installing a waste treatment facility the effluent will still be acceptable.
The price of such uncertainty comes high. If we underestimate, the cost of adding to an existing plant will certainly be far more than if the whole job were
done at the outset. On the other hand, overestimating might well have resulted
in needless expense.
All of this leaves the way open to reuse. In order to reuse, the water need
be cleaned up only enough to make it acceptable to the plant process and often
this means solids removal alone. Soluble contaminants -- always the most difficult to remove -- usually are acceptable to the process which placed them in the
water in the first place.
The effluent from an industrial plant usually is a conglomeration of many
small or large waste streams. These streams may range from relatively unpolluted cooling or seal water to streams heavily polluted with both solid and soluble
matter. In most cases, the most heavily polluted sources can be handled most
economically on a separate basis. The lightly polluted waters might either be
reused directly or at most with minimal treatment.
Another practical approach is to bring fresh water into the most critical areas
of the plant, then reuse the water in successively less critical applications until
the final effluent will have to receive treatment.
WISSEMBOURG FESCO PLANT
In the spring of 1967, Johns-Manville started up a new plant at Wissembourg,
France, producing FESCO roof deck board. The process was basically the same
as that used in other FESCO plants in the United States but there was one important difference. The Wissembourg plant was built with a completely closed water system.
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