Treatment of Industrial Wastewaters
by Physical-Chemical Processes
JU-CHANG HUANG, Associate Professor
K. A. NARASIMHAN, Research Assistant
MICHAEL G. HARDIE, Research Assistant
Department of Civil Engineering
Environmental Research Center
University of Missouri-Rolla
Rolla, Missouri
INTRODUCTION
Man since his beginning has considered water as an unlimited natural resource and
able to sustain various kinds of abuse. It is only very recently that he has begun to realize
that this supposedly limitless supply is dwindling and its quality is undergoing rapid
degradation, and that unless certain corrective measures are taken immediately, these
problems may go too far and surpass solution. Because of this, the public's attention toward
protection against water pollution has been nurtured in recent years and now has reached its
climax.
Federal and state governments have established increasingly stringent water quality
and effluent standards with which municipalities and industries must comply by certain
deadlines. Perhaps the most far reaching water pollution control bill that has been proposed
is the one which would call for the total elimination of pollutional discharges into the
Nation's navigable waterways from industries and municipalities by the year 1985.
Although the justification for this bill is quite controversial and its technical achievability as
well as economical feasibility are still uncertain at this moment, the attempt to legislate this
bill through the Congress will undoubtedly reflect the determination of the public and the
willingness of the legislators to clean up the Nation's waterways at the earliest possible date.
The intent of the proposed bill will not only be the abatement of water pollution problems,
but more importantly it is also aimed at achieving the ultimate goal of water reuse. The
practice of direct water reuse will become increasingly common in the near future since it
has been estimated that by the year 2000 the demand for water in the United States will
surpass that available through natural runoff.
For many years it has been recognized that conventional primary plus secondary
biological treatment is not able to produce effluents of sufficiently high quality to be
suitable for direct reuse, nor in many instances is it able to give adequate treatment so that
the effluent meets present day water quality standards. This is especially true when the
conventional method is applied to the treatment of certain industrial wastes which are either
relatively refractory or biotoxic. Because of these reasons, considerable research interest in
recent years has been focused on the development of some new and advanced waste
treatment technologies with a hope that these new technologies will either supplement the
existing inadequate conventional methods or even replace them completely. Also, many of
these new technologies are aimed at providing sufficient degrees of treatment so that the
treated effluents can be reused directly.
Since the advanced waste treatment research program was first undertaken by the Taft
Sanitary Engineering Center in 1960, a large number of prospective technologies have been
carefully screened and subjected to intensive studies. The majority of the new processes
which have been investigated are the so-called "physical-chemical" methods. In studying
these advanced treatment technologies, most investigators have concentrated their studies
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