One hell of an environmental protection program, but nobody seems to care.
EARTH DAY 2005
By Peter Maier, PhD, PE
It took physicians fifty years to accept Dr. Semmelweis’s advise to wash their hands to prevent
puerperal fever, so we should not be surprised that it is only twenty years ago that engineers
learned that EPA used a pollution test incorrectly and as a consequence not only ignored a large
portion of fecal waste in sewage, but all the pollution caused by urine and protein waste.
This, living in the 21st century, seems hardly possible and although nobody disputes the fact that
the test is incorrectly applied, the consequences have been successfully down-played by all
parties involved, including national environmental groups.
What are the consequences?
EPA used the test in regulations to set standards for ‘secondary treatment’, which Congress was
told, when it passed the CWA in 1972, represented 85% treatment.
Since the test, as used, only represents 40% of the pollution causing depletion of oxygen, EPA
only demanded 85% of 40% equals 35% treatment. Clearly inadequate to meet even the Act’s
interim goal of “swimmable and fishable” waters by 1983 and forget the Act’s final goal of
“elimination of all pollution” by 1985.
Besides the regulatory problems caused, there are several practical engineering problems:
1 It is not possible to evaluate the true performance of a sewage treatment plant
2 It is not possible to evaluate the pollution loadings on receiving water bodies
3 It is possible that sewage treatment plants are designed to treat the wrong waste.
Any of these problems by itself should be enough reasons to correct this essential test, but for
some reason that seems to be impossible. If similar mistakes were made in other engineering
fields, airplanes would not fly, boats would sink and bridges would collapse.
Considering the history of the Clean Water Act and what Senator Muskie’s stated on the Senate
floor: “This Act simple means that we can not use our rivers to treat our sewage any longer”,
Congress clearly intended to treat all the pollution in sewage and in order to do so allocated
billions of federal dollars.
But what is sewage and how does it impact open waters?
Sewage contains carbonaceous (fecal) waste, which is going to be used by heterotrophic
bacteria and thereby use oxygen. This phenomenon is called C-BOD or Carbonaceous
Biochemical Oxygen Demand. The nitrogenous waste (urine and proteins) in sewage is used by
autotrophic bacteria and they also use oxygen. This phenomenon is called N-BOD or
Nitrogenous Biochemical Oxygen Demand. However, besides exerting such an oxygen demand,
all forms of this nitrogenous waste (urea, ammonia, nitrates) represent nutrients that stimulate
the growth of alga. The later nutrient enrichment ‘pollution’ contributes to the eutrophication of
our water bodies.
C-BOD represents 60% and N-BOD 40% of the total BOD in raw sewage, when discharged into a
water body. To measure the total BOD would take 30 days, but researcher found that in
combination with a nitrogen test, one could use the 5-day reading of the test, to calculate the
ultimate BOD, thereby assuming that the 5-day reading solely represented the oxygen used by
Although all this is well described in the literature, it became common practice in the world to use
only the BOD5 test, as the pollution parameter impacting the dissolved oxygen concentration in
When EPA established treatment criteria for its NPDES (National Pollution Discharge Elimination
System) permits in 1973, it also based its ‘secondary treatment’ definition of 85% treatment solely
on the BOD5 testing, without any consideration given to nitrogenous waste.
Also ignored was the fact that the activities of autotrophic bacteria are not always delayed for 6
to 10 days and that in most cases the heterotrophic and autotrophic bacteria both used oxygen
during this five day period and the BOD5 reading therefore is C-BOD5 + N-BOD5.
This caused law enforcement problems and many sewage treatment facilities were fined for
exceeding their BOD5 permits, while a significant part of this reading was N-BOD5, which were
not regulated. Such facilities were in fact penalized for treating sewage better than was required
by their permits.
EPA did recognized the problems in 1983, but in stead of correcting the test procedure, EPA
allowed the addition of a chemical to the test, which only kills the autotrophic bacteria and thus
lowers the BOD5 test reading. It is estimated that 60% of all sewage plants, allegedly out of
compliance with their NPDES permits, got into compliance by adding this chemical to the test.
EPA in 1984, by an administrative ruling, lowered the goal of the CWA from ‘elimination of all
pollution” to a measly 35% treatment, without even informing the U.S. Congress. Since EPA does
not require the treatment of urine waste, rivers are still used as giant urinals by cities and nobody
has even questioned the EPA if such waters are ‘swimmable”.
Some members of Congress have asked EPA questions, but EPA convinced them that
nitrogenous pollution was not a problem and that if EPA would demand such treatment that it
would be very costly. An argument for politicians to quickly drop this issue, even tough EPA
never implemented their legislation.
EPA’s argument that better treatment would be more costly is another fallacy, proven by EPA’s
Most our open waters are now suffering from nutrient enrichments and thus excessive alga and
aquatic plant growth, which in many drink water reservoirs already is causing problems with the
treatment for drinking water.
The Clean Water Act was the second largest federal public works program and the fact that it not
only failed to clean up our open waters, but wasted billions of taxpayer’s dollars, solely caused by
a faulty applied test, should be unacceptable.