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Is Sewage Sludge a Safe and Useful Commodity?

by Alexander DeLuca, M.D.,; Originally posted: May 18, 2003; most recent editing: May 14, 2005.

This paper was written as an assignment for the Course P6300: Environment Sciences, Columbia University
Mailman School of Public Health, Professor Brandt-Rauf, , original hard copy submitted April 23, 2003

What is sludge, and where does it come from?

Sludge, or “biosolids,” is an end product of wastewater treatment plants; it is what is left after our best efforts to
decontaminate sewage and remove the water. Biosolids are a legacy of the Clean Water Act (CWA) of 1972,
which included a section entitled,  “Standards for the Use or Disposal of Sewage Sludge” (40 CFR part 503).
The CWA was a response to what was a tremendous problem of water pollution caused by the dumping of large
quantities of untreated sewage and waste industrial chemicals into rivers and oceans by cities and by the failure of
septic systems in smaller communities nationwide. From the CWA has sprung “what has become the largest
construction grants program in US history”
[Stauber and Rampton #1, 1995] Millions of homes and thousands of
businesses have been connected to centralized sewer systems and to complex, industrial, water treatment facilities.

The CWA mandated that treatment plants remove at least 85 percent of the pollutants in their wastewater streams,
and it established federal funding for the additional plants and for technological upgrading of existing facilities.
Sludge is what is filtered, concentrated, and removed by sewage treatment plants. Potentially toxic sludge, which
must be disposed of somehow, is the dark underbelly of the tremendous social, engineering, and scientific
accomplishment that is the CWA and its resulting initiatives and programs. By 1976 the federal government was
spending about 50 billion dollars a year to help municipalities meet standards of water purity.

Meanwhile, the sludge has been piling up. Since 1995, we have been producing some six to ten million tons of
sludge per year, of which about 60% is used in land application programs. Ocean disposal of wastewater residues
was prohibited in 1992 and since that time the “use of sewage sludge as soil amendments… or for land reclamation”
has increased in order to deal with this very significant waste disposal problem.
[Burke, 2002

“Toxic Sludge is Good for You!” [Stauber and Rampton #2, 1995]
In the third sentence of the Summary of the National Research Council’s (NRC) important scientific review of EPA’s
approach to the biosolids disposal problem it states, “Since the early 1970s, the EPA and the wastewater treatment
industry have promoted recycling of sewage sludge.”
[Burke, 2002 The EPA’s public relations strategy to promote the
land application of sludge was first outlined in a 40-page report published in 1981 and bureaucratically entitled:
“Institutional Constraints and Public Acceptance Barriers to Utilization of Municipal Wastewater and Sludge for Land
Reclamation and Biomass Production.” It warns that sludge farming projects may be opposed by small local groups who “feel their interests threatened,” for which the EPA prescribes strategies of either “aggressive” or “passive” public
[EPA, 1981] 

It is this high alignment of economic interests, worldview, and politics between the regulators and the regulated that is
the reason that an articulate and vociferous grassroots opposition to the land application of sewage sludge has survived
decades of an intense, well funded, EPA/Industry public relations campaign. More specifically, it is the fear that in its
focused effort to promote the land application of potentially toxic sludge as an economically attractive “fix” to the
sludge-disposal problem that the EPA failed to adequately design and set up statistically sophisticated epidemiological
studies necessary to detect harm to the public if in fact harm was occurring.

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The root problem
To examine the historical causes of the current sludge situation, we must look at the decisions made a century ago
mix human and industrial waste streams together using fresh flowing water as sort of magic carpet that was free for the taking and the responsibility of no one.

“The environmentally sound approach would have been to develop separate treatment systems
for human and industrial waste. Biological wastes should have been recycled … and businesses
should have been required to separately treat their chemical wastes on-site… At the time,
however, it seemed easier and cheaper to simply dump everything into a single common sewer
system… The problem with this system, however, is that it collects, mixes, and concentrates a
wide range of noxious and toxic materials which are then very difficult, if not impossible, to
separate and detoxify.”
[Stauber and Rampton #1, 1995]

The National Academy says there is no documented harm from sludge!
In July, 2002, the National Academy Press published a report by the NRC entitled, “Biosolids Applied to Land: Advancing Standards and Practices.” The Committee found “no documented scientific evidence that the Part 503 rule has failed to protect public health.[Burke, 2002]  The EPA and various wastewater treatment industry associations, such as the Association of Metropolitan  Sewerage Agencies (AMSA) and the National Biosolids Partnership (NBP) apparently feel vindicated by the report [;]
and have been quick to trumpet it.

The philosophical question whether failing to prove that the land application approach to sludge disposal has caused harm is the same thing as this policy being an unmitigated success, is beyond the scope of this paper. The NRC report is not, however, laudatory of the EPA despite the oft-quoted “no documented scientific evidence that the Part 503 rule has failed to protect public health” line. From the “Overarching Findings” sections of the NRC “Biosolids Applied to Land” document:

“[Additional] scientific work is needed to reduce persistent uncertainty about the potential for
adverse human health effects from exposure to biosolids… To assure the public and to protect
public health, there is a critical need to update the scientific basis of the rule, to (1) ensure that the
chemical and pathogen standards are supported by current scientific data and risk-assessment
methods, (2) demonstrate effective enforcement of the Part 503 rule, and (3) validate the
effectiveness of biosolids management practices.”
[Burke, 2002

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So why isn’t everybody happy?
Dr. Stanford Tackett, a chemist and lead expert, is one researcher who is outraged by the use of sludge as a fertilizer for crops which he feels “pose a more significant lead threat to the land than did the use of leaded gasoline.” He is also deeply concerned about and condemns the “selective science” and “manipulation of research money” used to rationalize sludge farming:

“Millions of dollars have been made available through EPA and other federal, state and local agencies,
for ‘beneficial use’ research. Toxicologists, public health scientists and medical researchers have not
had a similar money pot available to study the potential dangers and adverse health effects of sewage
[Stauber and Rampton #3, 1995

More generally, while it’s great that the EPA is finally agreeing in 2003, though somewhat vaguely and in broad strokes, to comply with the “Overarching Recommendations” of the NRC, specifically:

1.      To use modern risk-assessment methods to establish standards for chemicals and pathogens,

2.      To conduct a basic survey into the chemical content and pathogenic activity of sewage sludge,

3.      To establish a basic epidemiological framework prerequisite to implementing seemingly crucial
    human health investigations, and finally

4.      To increase the budget for biosolids such that these things be accomplished;


one has to ask why we have had to wait almost a quarter century for the EPA to take what sounds like a pretty basic,

epidemiological approach that a premier federal regulatory agency might have been expected to have had in place.

That the agency essentially had to be dragged, kicking and screaming, to do its basic scientific job that is essential to

its core mission of protecting the public health gives strong support to its critics’ claims that it has squandered public

funds by diverting them to use in a PR war.


Gone native – the regulated and the regulators look a lot alike…
What is wrong with the regulatory process at EPA? William Sanjour, who worked at the agency for 25 years, charges 
that an institutional bigotry has taken hold which, “prejudice manifests itself in countless EPA actions: in decisions 
to locate hazardous-waste facilities in already heavily polluted poor neighborhoods; in Superfund cleanups that ignore 
community concerns in favor of giving big bucks to favored contractors; [etc.]”
“EPA is soft on polluters [because] EPA personnel are much more comfortable with industry types, who 
are more likely than environmentalists to share their cultural background and outlook. Many EPA staffers 
aspire to high-paying corporate jobs through the "revolving doors" between government and industry. For 
instance, former EPA administrator William Ruckelshaus (a Republican) now works for waste hauler 
Browning-Ferris... Literally hundreds of career civil service EPA employees have left or retired from the 
agency to work for the companies they once regulated.” [Sanjour, 1997

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Where do we go in the short term?
Biosolids are the product of large, complex, centralized, industrial treatment plants. High tech got us into this
mess, and for the short term at least, high tech is going to have to get us out of it. There are technologies out
there that promise to reduce toxic sludge to elemental carbon and water, virtually eliminating a disposal problem.
For example,
a hydrothermal oxidation system which can process up to 9.8 dry tons per day of sludge “provides
an alternative method that addresses the health concerns associated with sludge disposal by completely
converting all organic matter in the sludge to carbon dioxide, water, and other innocuous materials.”

[Griffith and Raymond, 2002] 

There is another level of technology that we should deploy, though this frustratingly falls into the category of
‘Things we might have accomplished if we hadn’t spent decades  focused on land-application PR.’ Waterless
treatment systems are stand-alone, decentralized, on-site composting and drying toilets capable of directly
processing human wastes into a truly safe, useful soil additive. This is a mature technology that works very well
and which might have been widely deployed over the past decade.

“These dry systems are more economical than water-flushed... However, water-flushed toilets are so
entrenched in the cultural infrastructure that the transition to alternative waste systems has been blocked.
Instead, billions of dollars are spent on perfecting the mistake of waterborne waste systems: wastes are
first diluted in water and then, at great expense, partially removed.”
[Costner and Thornton, 1989]

Root problem redux – where do we want to be in 2103?
“At the time it seemed easier and cheaper just to dump everything into a common sewer system” is how we ended
up with all this toxic sludge. And decades of intense public initiatives like the Clean Water Act have left us with a
huge infrastructure and perhaps a sense of being stuck with it; that the die is cast – we’ve got this mixed
wastewater stream and all we can do is treat the hell out of it and spread the residue around and hope the toxins
don’t bite us in the ass.

Will our decisions today, and our actions and our failure to act, be judged a century from now as a “root problem”
of their wastewater system? Are we stuck with a mixed household/industrial wastewater stream into which we
haphazardly dump everything and then hope we can get all the really dangerous stuff out later? Or should we start
to do the large but eminently do-able job of fundamentally fixing our deeply flawed design? The EPA has
demonstrated the power of a well designed, multifaceted, consistent public relations campaign to influence public
opinion and policy, even to the extent of making toxic sludge seem as if it’s a ‘good thing.’ This same power
could be deployed to change the public heart and mind regarding flush toilets, separating the wastewater stream,
and the like.

 [Top of Page


      1.   Stauber, JC and Rampton, S #1. A Brief History of Slime. 1995.
(accessed April 23, 2003).

      2.   Burke, TA. Biosolids applied to land: advancing standards and practices. 2002.
National Research Council Committee on Toxicants and Pathogens in Biosolids
Applied to Land. Report Number 1, 1-266.
(accessed April 23, 2003).

      3.   Stauber, JC and Rampton, S #2.  Toxic Sludge is Good for You - Lies, Damned Lies,
and the Public Relations Industry. 1995. Common Courage Press; 1-256.

      4.   Environmental Protection Agency. Institutional Constraints and Public Acceptance Barriers to
Utilization of Municipal Wastewater and Sludge for Land Reclamation and Biomass
Production. 1981. EPA # 430981013; 1-109.

      5.   Stauber, JC and Rampton, S #3. Let them eat sludge. 1995.
(accessed April 23, 2003).

      6.   Sanjour, W. What's Wrong with EPA? 1997. In These Times Magazine;
(accessed April 23, 2003). 

      7.   Griffith, JW and Raymond, DW. 2002. The first commercial supercritical water oxidation sludge
processing plant. Waste Management; 22 (4); 453-459.

      8.   Costner, P and Thornton, J. Sewage Treatment Plants, We all Live Downstream: the Mississippi
River and the National Toxics Crisis. 1989.



Dr. DeLuca's Addiction, Pain, and Public Health Website

Alexander DeLuca, M.D., FASAM

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Originally posted:  5/18/2003

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