Excrement Happens

Reprinted from Rachel's Environmental & Health Weekly

Date: 1 Apr 1999
From: rachel@rachel.org

[Edited: Two issues combined, footnotes removed]


 Recently we came upon a history of the management of human excreta --
urine and feces -- starting back in the mists of time and working
forward to the present day.[1] It turns out that this unlikely topic
can tell us something important about the way humans make
environmental decisions. For that reason, we're going to recap the
story here. The original author, Abby A. Rockefeller, deserves credit
for all the original work, though not, of course, blame for any of our
lapses or misinterpretations in the retelling. Where we have
supplemented Ms. Rockefeller's history with additional facts, they
appear inside square brackets.

 * * *

 Humans began to lead a settled life, growing crops to supplement
hunting and gathering, only about 10,000 years ago. For all time
before that, humans "deposited their excreta -- urine and feces -- on
the ground, here and there, in the manner of all other land
creatures." The soil and its communities (including plants, small
animals and microorganisms) captured almost all of the nutrients in
animal excrement and recycled them into new components for soil. In
this way, the nutrients were endlessly recycled within the soil
ecosystem and largely kept out of surface water.

 As a result, what we call "pure water" is low in nutrients,
particularly the major nutrients nitrogen and phosphorus. Because
these conditions have existed for a very long time, life in lakes,
rivers, and oceans is accustomed to the relative absence of these
nutrients. Over the past couple of billion years, life has flourished
in this low-nutrient environment, growing complex and interdependent
in the process -- an aquatic condition we call "clean" and "healthy."

 When a body of water is suddenly inundated with nutrients --
especially nitrogen and phosphorus -- things change drastically. One
or a few organisms flourish and begin to crowd out the others. We can
all recall seeing a body of water that is pea-soup green from
overgrowth of algae. Such a water body is clearly sick, choked, its
diversity vastly diminished.

 Today, much of the surface water of the planet is in a state of ill
health because of misplaced nutrients. And a main contributing culprit
is misplaced human excreta.

 Long ago, human civilizations split into two camps regarding the
management of excreta. Many Asian societies recognized the nutrient
value of "night soil" (as it became known). For several thousand
years, and up until very recently, Asian agriculture flourished by
recycling human wastes into crop land.

 The opposing camp, particularly in Europe, had ambiguous feelings
about human waste -- was it valuable fertilizer or was it a nasty and
embarrassing problem to get rid of?

 In Europe, a pattern evolved: The first stage was urinating and
defecating on the ground near dwellings. As population density
increased, this became intolerable and the community pit evolved. For
privacy, this evolved into the pit privy or "outhouse" -- a privacy
structure atop a hole in the ground. Despite what many people may
think, the pit privy is not environmentally sound -- it deprives the
soil of the nutrients in excrement, and by concentrating wastes it
promotes pollution of groundwater by those same nutrients.

 Before the advent of piped water in the late 18th century, European
towns stored excreta in cesspools (lined pits with some drainage of
liquids) or in vault privies (tight tanks without any drainage). The
"night soil" was removed by "scavengers" and was either taken to
farms, or dumped into pits in the ground or into rivers. In general,
Europeans never developed a clear and consistent perception of the
nutrient value of excrement, as Asians had done.

 In ancient Rome, the wealthy elite had indoor toilets and running
water to remove excrement via sewers. Later, European cities developed
crude sewer systems -- usually open gutters but sometimes covered
trenches along the center or sides of streets -- though they had no
running water until the 18th or even 19th centuries. The putrefying
matter in these stagnant ditches did not move until it rained -- thus
the name "storm sewers" -- and many cities prohibited the dumping of
human wastes into such sewers.

 With the advent of piped water, things changed dramatically. In this
country, the first waterworks was installed in Philadelphia in 1802
and by 1860 136 cities were enjoying piped water systems. By 1880, the
number was up to 598. With piped water, per-capita water use increased
at least 10-fold, from 3-5 gallons per person per day to 30-50 gallons
per person per day or even more.

 Water piped into homes had to be piped out again. This caused
cesspools to overflow, thus increasing the problems of odors and of
water-borne diseases. To solve these problems, cesspools were
connected to the city's crude sewer systems which ran along the
streets. The result was epidemics of cholera. In Paris in 1832, 20,000
people died of cholera. Around the world, the combination of piped
water and open sewers has consistently led to outbreaks of cholera.

 To solve this problem, engineers designed closed sewer systems, pipes
using water as the vehicle for carrying away excrement. This solution
engendered a debate among engineers: some wanted to return sewage to
agricultural land, others argued that "water purifies itself" and
wanted to pipe sewage straight into lakes, rivers, and oceans. By
1910, the debate was over and sewage was being dumped into water
bodies on a grand scale.

 In the cities, cholera epidemics abated. However, cities drawing
their drinking water downstream from sewage discharges began having
outbreaks of typhoid. This engendered another debate: whether to treat
sewage before dumping it into water bodies used for drinking, or
whether to filter drinking water. Public health officials favored
treating sewage before dumping it; sanitary engineers favored dumping
sewage raw and filtering water before drinking. The engineers
prevailed. As cities began to filter and disinfect their drinking
water, typhoid abated.

 Throughout the 20th century, the U.S. and Europe industrialized
rapidly. Industry developed a huge demand for low-cost waste disposal,
and sewers were the cheapest place to dump because the public was
paying. As the pressure for greater waste disposal capacity increased,
industrialized nations allocated vast sums of money to construct
centralized sewer systems to serve the combined needs of homes and

 As a result, the nutrients in excrement became mixed with industrial
wastes, many of them toxic. So by the 1950s, essentially every body of
water receiving piped wastes was badly polluted with a combination of
excessive nutrients and toxicants. This led to a demand to treat
wastes before dumping them into water. Thus began the "treatment"
phase of the "get rid of it" approach to human waste.

 As centralized sewer systems evolved, first came "primary treatment."
This consists of mechanically screening out the dead cats and other
"floatables." All other nutrients and toxic chemicals remain in the
waste water that is discharged to a river or ocean.

 Next came "secondary treatment" which speeds up the biological
decomposition of wastes by forcing oxygen into them, by promoting
bacterial growth, and by other means. This is an energy-intensive
process and therefore expensive. Unfortunately, it, too, leaves many
of the nutrients and toxic chemicals in the discharge water.

 [The Congressional Research Service recently estimated that the
federal government spent $69.5 billion on centralized sewage treatment
plants, 1973-1999.

 Despite this huge expenditure, the Congressional Research Service
said in 1999, "States report that municipal discharges are the second
leading source of water quality impairment in all of the nation's
waters (rivers and streams, lakes, and estuaries and coastal waters).
Pollutants associated with municipal discharges include nutrients...,
bacteria and other pathogens, as well as metals and toxic chemicals
from industrial and commercial activities and households."[2]]

 To the extent that primary and secondary treatment are successful,
they move nutrients and toxicants (combined) into a new form: sludge.
Sludge is the de-watered, sticky black "cake" created in large
quantities by modern sewage treatment plants. Sludge contains
everything that can go down the drains in homes and industries and
which a treatment plant is able to get back out.

 In the FEDERAL REGISTER November 9, 1990, U.S. Environmental
Protection Agency describes sludge this way:

 "The chemical composition and biological constituents of the sludge
depend upon the composition of the wastewater entering the treatment
facilities and the subsequent treatment processes. Typically, these
constituents may include volatiles, organic solids, nutrients,
disease-causing pathogenic organisms (e.g., bacteria, viruses, etc.),
heavy metals and inorganic ions, and toxic organic chemicals from
industrial wastes, household chemicals, and pesticides."

 Industry is currently using 70,000 different chemicals in commercial
quantities; any of these may appear in sludge. About 1000 new
chemicals come into commercial use each year, so any of these, too,
may appear in sludge. A description of the toxicants that may be found
in sludge would fill several books. The U.S. General Accounting Office
has reported -- not surprisingly -- that municipal sludge contains
radioactive wastes (from both medical and military sources).[3]

 With hundreds of sewage treatment plants producing toxic sludge in
mountainous quantities, the next question was, what in the world to do
with it?

 For many years, coastal cities dumped sewage sludge into the oceans,
where it created large "dead zones" that could not support marine
life. Other communities dumped their sludge into landfills, where it
could pollute their groundwater. Still others incinerated their
sludge, thus creating serious air pollution problems, then landfilled
the remaining ash or simply heaped the ash on the ground for the wind
to disperse.

 In 1988 Congress outlawed the ocean dumping of sewage sludge. At this
point, many communities faced a real waste crisis. There was no safe
(or even sensible) place to put the mountains of toxic sludge that are
generated every day by centralized sewage treatment systems.

 It was at this point in history that U.S. Environmental Protection
Agency (EPA) -- feeling tremendous pressure to "solve" the sludge
disposal problem -- discovered that sewage sludge is really "night
soil" -- the nutrient-rich product that has fertilized crops in Asia
for several thousand years. EPA decided that the expedient thing to do
with sewage sludge was to plow it into the land.

 Shortly after 1992, when the ban on ocean dumping went into effect,
EPA renamed toxic sludge "beneficial biosolids," and began
aggressively campaigning to sell it to the American people as
fertilizer. (See REHW #561.)

 * * *

 To recap where we are: Cities began to provide running water into
homes in the early 19th century. Water piped into homes had to be
piped out again, often into open sewer ditches running in the streets.
Outbreaks of cholera followed. A debate ensued: should sewage be
transported back to farms, where the nutrients had originated, or
should it be disposed of by dumping it into bodies of water? Although
many cities for a time transported sewage to farms, by 1920 most
sewage was being piped directly into bodies of water. This was a
crucial choice.

 Once the network of sewer pipes began to grow, industry saw these
public pipes as a cheap place to dump industrial wastes. As a result,
corporations began to dump all manner of toxicants into the
nutrient-rich sewage stream. This was another crucial choice. Once
they were mixed together, nutrients and industrial poisons could not
be separated at any reasonable price. Therefore the whole mess became
a toxic waste disposal problem and excrement lost its value as a
fertilizer. Dumping it into water bodies accelerated.

 By the 1950s, most of the nation's waterways were badly contaminated
with a combination of nutrients and toxicants. This gave rise to a
demand for treatment of waste prior to disposal. Pipes that used to
carry toxic sewage into streams and oceans now began to carry it into
centralized "wastewater treatment plants" or "publicly owned treatment
works" (POTWs).

 Wastewater treatment plants remove the solids and some of the
chemicals, creating a black, mud-like "sludge" in the process. It's a
trade-off: improved wastewater treatment means cleaner discharge water
but it also means more sludge and worse sludge (more toxic). Now a
new, and truly intractable, problem appears: what to do with mountains
of toxic sludge?

 Communities with access to the ocean began dumping sludge there. New
York dumped its sewage sludge 12 miles offshore; when that place
developed obvious contamination problems, the dumping was moved to a
spot 106 miles offshore, where, to no one's surprise, contamination
soon developed.

 The use of water to carry sewage, and the use of centralized
wastewater treatment plants, had great political appeal for several
reasons. Most political authorities tend to favor centralized
solutions because they basically don't trust people to handle their
own problems. Secondly, as we have noted, industry needed a cheap
place to dispose of its wastes. [In 1997, according to the
Congressional Research Service, industry "dumped 240 million pounds of
wastes with hazardous components" into municipal sewers.[2]] Third,
and perhaps most important, laying sewer pipes and building
centralized sewage treatment plants is extremely costly and
engineering firms receive 20% of the initial cost. [Between 1970 and
1993, the federal government appropriated $69.5 billion for sewage
construction projects. The Congressional Research Service recently
estimated that between now and the year 2016 (17 years), the federal
government will spend another $126 billion on sewage projects.[2]
These are serious amounts of money.] Only the Federal Highway
Administration [and the military] spend more public money on
construction. [If even a small fraction of this sewer money is kicked
back at election time by consultants, lawyers, investment bankers and
engineering firms, it can go a long way toward keeping the present
crop of politicians in office.]

 In the 1970s, many environmentalists and public health officials
favored centralized sewage treatment because it seemed to offer an
improvement over dumping raw wastes into waterways. The Clean Water
Act of 1977 was essentially a sewering act. Everyone was then locked
into centralized wastewater treatment systems.

 In 1988, Congress discovered that sludge dumping in the oceans was
harming marine life, and the practice was banned as of 1992. This
created a massive problem for American cities: [11.6 billion pounds of
sludge (that's the dry weight, not counting the water it contains[3])
has to go somewhere, year after year.]

 At that moment, EPA decided that the U.S. now needs to mimic 100
generations of successful farmers in Asia, returning human excrement
to farmland.

 However, EPA has overlooked two important differences between modern
sewage sludge and traditional "night soil" (unadulterated human

 1) Most of the nitrogen in human waste is in the urine and is
water-soluble, so it is not captured in the sludge. Therefore, if
sludge is going to substitute for commercial fertilizer, you have to
use a lot of it to get enough nitrogen. And (2) when you add a lot of
sludge to soil, you are also adding a lot of toxic metals and a rich
(though very poorly understood) mixture of organic chemicals and, very
likely, radioactive wastes as well.

 EPA has addressed the toxic metals by telling farmers to add lime to
their soil along with the sewage sludge, to prevent the soil from
becoming acidic. If soil turns acidic, then toxic metals begin to move
around, either leaching down into groundwater or moving upward into
the crops (which, by definition, are part of some food chain). If
soils are alkaline (the opposite of acidic), the metals move more

 [What EPA has overlooked is the fact that ordinary rain is slightly
acidic, not counting the excess acidity provided by "acid rain."
Normal rain drops falling through the atmosphere dissolve small amount
of carbon dioxide, forming carbonic acid. Normal rain has a pH of 5.6
whereas 7 is neutral. Therefore, if soils are not kept alkaline by the
regular addition of lime, sooner or later normal rain will begin to
leach excess metals out of many soils. The only way to prevent this is
to keep the excess metals out of soils in the first place.]

 In sum, plowing sewage sludge into soils is essentially guaranteed to
harm many of those soils as time passes. [See REHW #561.] [As we know
from the ancients who poisoned their soils with irrigation salts, a
nation that poisons its farmland is a nation that doesn't have a
long-term future.]

 A series of bad decisions made during this century has brought us to
an impasse: sewage sludge is unmanageable because you can't know from
day to day what is going to be in it, and so you cannot monitor its
contents.[4] (Even if you could manage the scientific problems
inherent in monitoring an unknown mixture of unknown substances, as a
practical matter there isn't any government agency with enough staff
to monitor the nation's sludge.)

 Therefore -- as heroic a task as this may seem -- it is time to
re-think centralized water-carriage sewage treatment systems. The
present systems were not designed to produce useable products and
therefore the DESIGN of present systems is the root of the problem.

 Three policy goals are needed: (1) Sewer avoidance (stay off or get
off water-carriage, centralized sewer systems). (2) Promote low-cost,
on-site resource recycling technologies, such as composting toilets,
that avoid polluting water and preclude wasting resources. (3) Price
water right so that the market works to keep it clean, not contaminate
it with excreta.[4]

 [For individual households, real solutions are already available:
zero discharge household waste systems. An excellent new book by David
del Porto and Carol Steinfeld, THE COMPOSTING TOILET SYSTEM, will
dispel any fears you may have that composting toilets are a step
backward.[5] With microflush toilets and vacuum-flush toilets now
readily available, you can have the bathroom of your dreams, yet
compost your household wastes into an odor-free product that is
entirely satisfactory as agricultural fertilizer. These days, there
are companies that will manage the system for you, including removing
the compost. Your household waste system can be installed, maintained,
and managed by professionals, just like your electrical and heating

 But what about apartment buildings and office buildings in cities?
Although we know of no one who has applied it, the technology
certainly exists for manufacturing building-scale waste systems based
on anaerobic digesters, which would produce methane gas and
fertilizer. As Abby A. Rockefeller said recently in an interview,
"Surely, human ingenuity can do this." Such systems would be cheaper
than current sewage systems because they wouldn't require miles of
underground pipes to connect to a centralized sewage treatment plant,
and they would conserve hundreds of billions of gallons of water each

 [Every time we flush the toilet, 3.3 gallons of drinking water are
degraded. At 5.2 flushes per day (average), each of us presently
degrades 6260 gallons of drinking water each year to flush away our
1300 pounds of excrement -- 1.6 trillion gallons of water per year in
the U.S.]

 Naturally, we would need to keep toxicants out of these composting
systems, but that has always been true (even though we have ignored
this fact) and we might as well face up to it now. Toxic household
products will have to be phased out as part of any plan for
sustainable living.

 Toxic industrial wastes should be managed by the industries that make
them, not dumped into the environment that sustains all life. Unusable
wastes are a sure sign of inefficiency.

 Lastly, what to do with today's mountains of toxic sludge? Obviously
they must be handled as hazardous wastes because that's what they are.
[Probably above-ground storage in concrete buildings is the only
satisfactory solution at the present time. (See REHW #260.)]

 [You say we can't do any of this because we've been doing it another
way for 100 years? Ask yourself, what kind of people would dump their
excreta into their drinking water in the first place? And what kind of
people, faced with workable, cheaper, more environmentally sound
alternatives would continue to insist that dumping their excreta into
their drinking water is the only way to live?]


Environmental Research Foundation
POB 5036, Annapolis, MD 21403
Fax (410) 263-8944; E-mail: erf@rachel.org

All back issues are available by E-mail: send E-mail to
info@rachel.org with the single word HELP in the message
Back issues are also available from http://www.rachel.org
To start your own free subscription, send email to listserv@rachel.org
with the words SUBSCRIBE RACHEL-WEEKLY YOUR NAME in the message.