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E-M:/ Slugging through the Sludge
Enviro-Mich message from joonmck <email@example.com>
I'll bet that more Lansing citizens know about Peter MacNicol's desire
for a "clean bowl" (on Fox's Ally McBeal) than know that nearly 70% of
their urine and feces is converted into sewage sludge and trucked to
local farms in Ingham, Clinton and Eaton Counties.
Yes, it's NOT excrement exactly, but it's not black gold either. Once
it's flushed down the toilet, it's HISTORY for most folks. And that's a
form of environmental illiteracy!
If we want to create an army of environmentalists, aware of the local
ecology, we MUST help folks think the totality, see the whole, place the
pieces of the puzzle together. And that means looking at a little real
In 1999 Ingham County generated 6,345 tons of sewage sludge and an
estimated 4,323 tons were trucked to more than 20 farm fields in
Clinton, Eaton and Ingham Counties. The largest generator was the
Lansing Wastewater Treatment plant which created 5,777 tons of sludge
(and although there are more than 230 pre-treatment operations in
Lansing, there are still quite a lot of industrial chemicals that make
their way into the darling doo). Lansing land applies about 65% of its
sludge, the rest is land-filled.
WORD Games: In the trade it's referred to as "land application of sewage
sludge," though federal and state officials prefer the term "biosolids,"
a term nestled somewhere between euphemism and science.
In a growing number of quarters, there is debate about the practice.
Some stress that, if done right, "land application of treated wastewater
and sludge are good technologies in harmony with nature, provided that
industrial pre-treatment has resulted in high quality effluent or good
sludge that will bio-degrade." Others say, "we only have three choices
of what to do with it (land apply, burn/ash/landfill, or just landfill
it directly). Actually, there are other options, but before I refer you
to them (in a later post), let's get into the WAY-BACK MACHINE.
"Sherman, are you ready?"
HURLING THROUGH TIME ^&%$&*&(^&*%^%(^$*^())*&)&()((*!!
Before the 1980s most of our excrement eventually was dumped into our
rivers, land filled or incinerated.
We can contrast today's black, mud-like sewage sludge with the excreta
of past civilizations. For much of human history many Asian societies
recycled human waste into cropland, recognizing its high nutrient value.
"Night soil," as it was called, was an excellent way of managing human
waste. Unlike today's modern sewage effluent, it was relatively pure. It
did not contain PCBs, cadmium, arsenic and the thousands of human-made
chemicals that today's sludge contains (most in negligible amounts, yet
still unmeasured), owing to the contributions of household and
industrial contaminants dumped down the drain.
Indeed, industrial societies have changed their approach to managing
human sewage numerous times over the past two centuries. In the 19th
century much of this sewage was pumped to open sewer ditches running on
streets. Cholera outbreaks were one result. By 1920 most sewage was
piped instead into our rivers and streams. But by the 1950s most of the
country's waterways were badly polluted. Demands were made for treatment
of waste prior to disposal. With the growth of the underground sewage
pipe infrastructure, (achieved at public expense), corporations began to
dump a wide variety of toxicants into the sewage stream. But it proved
impossible to separate the sewage nutrients from all of the toxic waste
in the pipes. When some of the toxins were removed (or pre-treated), it
was often at a high expense.
Sewage sludges contain nutrient and organic matter that fertilize crops;
but they also contain biological pathogens (bacteria, viruses and
protozoa). The goal of sewage treatment (and pre-sewage treatment before
industrial waste reaches the wastewater treatment plant) is to remove or
diminish the biological pathogens and to lower the amounts of nine heavy
metals like lead and mercury in the sludge. These heavy metals are the
"chemical solids" and "physical solids" lurking in "biosolids".
Finally, in the 1980s, the EPA evaluated different methods of disposal
to determine the environmental health effects of each. They determined
that land filling and incineration each had health and environmental
drawbacks and offered none of the benefits of applying sewage sludge to
farms, forests, and golf links. Soon the EPA expressed a preference for
land application, thus signaling a return to an age-old remedy. Or was
I'll not go any deeper into the muck of history right now. Instead I
wish to focus attention on this table that compares Michigan's metal
standards with those recommended by the Cornell Waste Management
Institute. Based on their research, the Cornell thinkers developed
tougher standards for each of the nine metals that the EPA chooses to
regulate. The table below compares standards from the EPA and Cornell
with the actual metal levels reported for Michigan as a whole. While
Michigan easily passes the EPA standards, it fails eight of the nine
standards set forth by the Cornell researchers.
Comparison of Michigan 1997 Sewage Sludge Contaminant Levels
with Alternate Standards
(In Parts Per Million)
Metal // EPA Reg. Limits // Michigan AVG. '97 // Cornell Standards
Arsenic // 75 // 8 // 1-10
Cadmium // 85 // 4 // 2
Copper // 4300 // 459 // 40-100
Lead // 840 // 61 // 0
Mercury // 57 // 2 // 1
Molybdenum// 75 // 13 // 4
Nickel // 420 // 46 // 25-50
Selemium // 100 // 8 // 5
Zinc // 7500 // 831 // 75-200
PCBs //No Standard // Not measured // 1
Other countries have far stricter standards for some of these metals.
For example, the maximum allowable soil concentrations in the U.S. for
zinc is 1,400 ppm; while for Denmark it is 100 ppm, and for the
European Union it is 300 ppm. For cadmium the U.S. ceiling is 19.5 ppm,
in contrast the Netherlands where it is 0.8 ppm.
I am aware that there are scores of hard-working people in the DEQ who
wrestle with these issues daily. Towards these ends, the DEQ has even
recently placed a link to the Cornell Waste Management group on its
All I wish to do now is provoke debate on the practice!
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