INDUSTRIAL EFFLUENT STANDARDS
FOR TOXIC POLLUTANTS
Murray P. Strier, Chemical Engineer
James D. Gallup, Chief
Office of Quality Review
U.S. Environmental Protection Agency
Washington, DC 20460
On the original list of 129 priority pollutants singled out in the 1977 Clean Water Act
Amendments, there were 96 nonpesticide single and groups of organic compounds. There
was at best, very little information available on the treatability for removal from industrial
wastewater of singular organic compounds by unit processes and systems. Up until then,
organic pollutants were assessed by generic pollutant parameters such as BOD, COD, TOC
and TSS.
Although structure-activity correlations have had universal application in other fields,
it appeared to not been used in any depth in pollution control of toxic organics. This article
is on the efforts to date by the authors, with special emphasis on the application to development of treatability-based effluent guidelines limitations. In essence, this served as a supplemental study to the overall broad program by EPA to develop regulations for priority
pollutants based on extensive industrial waste surveys of 21 primary industrial categories.
Table I is a summary of our original data set, which served to establish our six designated
clusters on estimated ranges of theoretical effluent limitations, called ETEL values [1, 2].
Such physical-chemical properties as molecular weight, boiling point, azeotropic boiling
Point, composition and solubility, were used initially. However, compound functionality
and end-use application rounded out our judgment as well [ 1 ]. Compounds used as substitutes in end-uses are bound to have comparable intrinsic characteristics.
In the discussion which follows, an effort is made to show how our rationale can be used
to serve as a scientific, cost-effective basis for setting effluent guidelines limitations, analyzing treatability data and for possible intelligent use of generic pollutant parameters, as
surrogates for certain broad classes of toxic organic pollutant compounds [3].
FUNDAMENTAL THERMODYNAMIC CONSIDERATIONS
In our study, the five unit treatment processes given in Table II were selected on the basis
that they were already in use or would be expected to be used in the near future in treatment systems for the removal of organic priority pollutants from industrial wastewater [ 1 ].
Included are key physical-chemical parameters which were deemed relevant and most of
which can be considered as amenable to correlation with chemical structure. For the most
Part, especially in its early stages, our correlations applied either to single comounds in
water, or else, in relatively clean industrial wastewater matrices. For all of the five treatment
options, solubility plays a dominant role, even when biochemical oxidation is concerned, as
will now be discussed.
Applying the Gibbs free energy relationship, AG°, for the distribution of a solute between
two media, e.g., octanol-1 and water, as is the case for the partition coefficient, at equilibrium,
AG° =-RT/na2/ai   -  -KP (1)
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