[Digestion] High costs of biogass plants in Norway
David
david at h4c.org
Mon Dec 6 11:18:50 CST 2010
Dear Dr. Karve,
On 12/5/2010 8:48 PM, Anand Karve wrote:
> Dear Paul, [...]
> I have not heard of a single accidental explosion or of a fire
> arising from a biogas plant...
When I was doing research for the biogas handbook, I returned
repeatedly to the venerable Sewage Works Journal, one of the early of
the periodicals (if not the earliest) devoted to AD, in its case
dealing with municipal sewage. In several issues there were reports of
explosions-- this of course was in the twenties and thirties-- where
workers would open large tanks without any precautions, and an
explosion would result. In some cases people simply disappeared-- no
recognizable fragments were found, according to the reports.
> There were even reports from South America of a sausagelike biogas
> plant made out of relatively thin plastic film. I don't think there
> has been an accident with any of those, but something like that
> would never be allowed in Europe or USA.
I've not seen any reports of explosions with plastic bag digesters
either. But in terms of their use in the US, actually in a series of
classes I have recently initiated about biogas, one of the key aspects
is that every participant leaves with a ~200 gal plastic digester kit.
These classes have been held from Hawaii to Pennsylvania, soon in Los
Angeles and Iowa, and we are negotiating in a number of other places
including Australia (maybe to meet Paul?) and Guatemala. In any case
the point, as may surprise you, is that in fact there are no
regulations of which I know in the US that are /specific/ to the use
of (plastic bag or similar) small digesters. Someone asked me about
such regulations recently, and my response was that (again, to the
limits of my knowledge) any regulations that would apply would be
about other issues. For example:
> There also appear to be rules about effluents from a biogas plant.
Where human wastes, or other potentially environmentally or medically
harmful materials are used as substrates, there is indeed a forest of
regulations, federal, state and local, which would or may apply. Thus,
for example, if a small digester were to be fed humanure, then a
building inspector might reasonably classify it as a septic tank, and
apply the relevant building codes or health regulations. Likewise,
either out of ignorance or with some justification (depending on how
it has been constructed and how it is being used), someone with a
clipboard might decide that a small digester was hazardous under some
regulation or other, but again, I feel fairly confident if not
entirely certain that nowhere in the US are there regulations which
pertain to small biogas digesters as small biogas digesters. If it is
classified as something else-- a septic tank or a hazardous gas
storage unit, for example-- then some regulations may pertain. In this
instance, then, if one loses the classification battle, one may lose
the regulation war.
> Antibiotics were mentioned in one of the previous postings. Do they
> really persist in the effluent?
Some antibiotics are indeed very persistent. See, for example, this
paper <http://info.ngwa.org/gwol/pdf/042379994.pdf>.
d.
--
David William House
"The Complete Biogas Handbook" |www.completebiogas.com|
/Vahid Biogas/, an alternative energy consultancy |www.vahidbiogas.com
|
"Make no search for water. But find thirst,
And water from the very ground will burst."
(Rumi, a Persian mystic poet, quoted in /Delight of Hearts/, p. 77)
http://bahai.us/
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