Thalocean2 wrote:

Yes, it is a problem with human waste as well. That's why the human waste that
is spread all over farms in many states is first spun to remove the heavy
metals. It's a natural part of humans, dogs, cats etc. waste and when it's
concetrated to one small area, (your garden) the heavy metals can and do build
up to toxic levels. Do a quick search and look at all the court case documents
where farmers are sueing because their fields are ruined...



I assume that by human waste, you mean sewage sludge, since the
collection of human waste is basically only done at sewage treatment
plants (except for a very few outback places that still use privies).
The occurrence of heavy metals from sewage sludge is not necessarily
related to heavy metals in human waste. The heavy metals in the sewage
comes from people's practice of dumping everything down the drain in
addition to human waste.

Moreover, the availability of animal waste in large quantities (thank
you McDonalds and Col. Sanders) would render the collection of human
waste not economically feasible on a large scale outside of the sewage
treatment plants.

I have never heard of anyone spinning human waste before applying it to
fields, and I don't believe that spinning or centrifuging sewage sludge
containing heavy metals would separate them out. This process would be
extremely expensive and time consuming since the sludge would have to be
liquefied so that the heavier particles would be mobile enough in the
soup that they could settle out. The centrifuging equipment would be
costly and the same result could be obtained by letting the liquid
settle for an extended period of time. I am open to any references you
might be able to supply for this practice.

I have never heard of anyone spinning human waste before applying it to
fields, and I don't believe that spinning or centrifuging sewage sludge
containing heavy metals would separate them out.

http://www.apfn.org/apfn/waste.htm

In article , Dwight Sipler
wrote:

I assume that by human waste, you mean sewage sludge, since the
collection of human waste is basically only done at sewage treatment
plants (except for a very few outback places that still use privies).
The occurrence of heavy metals from sewage sludge is not necessarily
related to heavy metals in human waste. The heavy metals in the sewage
comes from people's practice of dumping everything down the drain in
addition to human waste.

Moreover, the availability of animal waste in large quantities (thank
you McDonalds and Col. Sanders) would render the collection of human
waste not economically feasible on a large scale outside of the sewage
treatment plants.

I have never heard of anyone spinning human waste before applying it to
fields, and I don't believe that spinning or centrifuging sewage sludge
containing heavy metals would separate them out. This process would be
extremely expensive and time consuming since the sludge would have to be
liquefied so that the heavier particles would be mobile enough in the
soup that they could settle out. The centrifuging equipment would be
costly and the same result could be obtained by letting the liquid
settle for an extended period of time. I am open to any references you
might be able to supply for this practice.

The problem of heavy metals in municiple waste & sludge is monitored &
ameleorated by several methods. Citizens should be on top of it lest
government decide to do it badly during money-crunch times. Often the
organic pollutants are very easy to remove; the heavy metal components are
more expensive to get rid of & any really polluted municiple wastes should
be rejected for compost purposes. Still & all, any attempt to key the
source of heavy metals in municiple sludge & waste to carnivores & pets is
so absurd it outdoes the usual level of superstitious horror of cat & dog
poo. The problem has to be nipped at the ACTUAL key sources of industrial
waste, flushed consumer products, fertilizers, pesticides, & machine
pollutants (chiefly automobiles).

-paghat the ratgirl

--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
-from Peter Newell's "Wild Flowers"
See the Garden of Paghat the Ratgirl: http://www.paghat.com/

Thalocean2 wrote:

[ref: spinning human waste before applying it to
fields]

http://www.apfn.org/apfn/waste.htm


Thanks for the reference. It does refer to sewage sludge and states "At
the state-of-the-art West Point Treatment Plant in Seattle, raw sewage
is digested, heated and spun, until it's just right for shipment to the
fields." The article goes on to say that there is some concern being
expressed by Cornell University researchers and describes problems
arising from the practice and in particular from the actions of one
farmer.

A quick check on Google for "heavy metal" sludge spin yielded a large
number of references to rock bands or political spin on sludge
questions. I found no other reference to (physically) spinning the
sludge, although I did not look at all 1000 listed links due to lack of
time.

I would point out that the purpose of spinning is not specified in the
article. I suspect that the purpose is to separate the liquid and solid
components (not necessarily the organic and heavy metal components)
since the stuff that is spread on fields is the solid component. The
liquid component is probably 99% water, and adds weight to the sludge,
so they want to dry it as much as possible before paying someone to
truck it somewhere.




For the record, I am *not* in favor of using sewage sludge on
food-producing land. The reason is that I consider the material
inadequately controlled, particularly in the heavy metal category.
However, I believe that the heavy metals in sewage sludge come from our
hands, not from some other part of our anatomy. It's the other stuff we
put down the drain that is the problem.