INDUSTRIAL PRETREATMENT:  A QUESTION OF CREDIT
Robert G. O'Dette, Chief
Technical Section
Tennessee Division of Water Quality Control
Nashville, Tennessee 37219
From Purdue to Pasadena and Duluth to Dallas, the road to government regulations
is paved with good intentions, but in these times of high inflation, low productivity, and
serious unemployment, how much regulation is enough and how much is too much? Last
year thousands upon thousands of bills and resolutions were introduced in Congress and
many of them received considerable publicity because they were in some way aimed at the
regulation of business. However, what largely escaped the attention of the press and public
was the cascade of federal rules, regulations and directives pouring forth daily from the
offices of government agencies. Unlike much legislation which is introduced but never
passed, each of these regulations carry the same weight as any bdl signed into law by the
President. At last count, there were more than 61,000 pages of federal regulations! When
one stops to think of the impact of the pretreatment regulations which represent a minute
fraction of the total, it is difficult to understand how people can continue to do business
in this country and easy to understand why we are at the threshold of a major economic
recession if not depression.
The goals and objectives of the Clean Water Act (CWA) relative to industrial pretreatment
are valid, because there are many potential problems associated with the discharge of industrial wastewaters into municipal sewerage systems. In Section 307(b) of the CWA, Congress
charged EPA with the responsibdity of establishing pretreatment standards for podutants
that are determined not to be susceptible to treatment by the POTW or that would interfere
with the operation of, or otherwise be incompatible with, such treatment works. Industrial,
as well as state and local government, response to the resultant pretreatment regulations
and categorical pretreatment standards has been justly critical in regard to legal direction,
standards rational and the cost versus environmental benefits.
The most distasteful pill for industry to swallow is being required to provide pretreatment
which is not necessary to protect the unit operations, sludge, or pass-through aspects of
publicly owned treatment works (POTW). The well-publicized NRDC consent decree,
essentially requires EPA to establish technology-based pretreatment for 21 industrial
categories and 65 toxic substances (129 priority pollutants). These pretreatment standards
wdl be based upon the capabilities and/or estimated capabilities of technologies to remove
pollutants on an industry-by-industry classification rather than the need to protect the
POTW or the receiving water quality. In other words, many industries, depending on location, will be required to provide wastewater treatment for the sake of meeting a nationally
developed standard rather than meeting a condition necessary to protect the unit operations, sludge handling and disposal, and effluent limitation at the POTW. The inherent
deficiencies associated with this concept are shown in Figure 1.
Figure 1 shows the relationship between poUutional load and dry-weather, low-flow
conditions experienced at the POTW. The dry-weather, low-flow rates are used because
they reflect the most critical period relative to the domestic ddution factor. The diagonal
line represents the influent concentration of the pollutant that must not be exceeded to
protect unit operations at the POTW and prevent pass-through or any other limiting factor,
such as sludge contamination. The horizontal line toward the upper third of the graph
represents the actual pollutional load in the raw industrial discharge. The horizontal line
toward the lower third of the graph represents the pollutional load that would be discharged
by the industry in question if that industry met the appropriate EPA pretreatment limit.
This graph demonstrates that there could be flow conditions in some communities
whereby no pretreatment would be necessary for POTW protection, whde in other commu-
911