Aquaponics Digest - Fri 12/12/97
Message 1: Re: Economics/Sustainability of production
from Jack Rowe
Message 2: Re: economics/sustainability of production
from Jack Rowe
Message 3: Re: Re: economics/sustainability of production
from YankeePerm
Message 4: Re: Re: economics/sustainability of production
from "H.Doelle"
Message 5: Re: economics/sustainability of production
from "H.Doelle"
Message 6: Re: Adaptable Systems - was economics/sustainability of production
from JCurts2318
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| Message 1 |
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Subject: Re: Economics/Sustainability of production
From: Jack Rowe
Date: Fri, 12 Dec 1997 11:09:11 -0500
>Jack Rowe wrote:
> In Asia, fish ponds receive much of their necessary phosphorous =
>and calcium from animal, human and bird manures, with =
>animal pens and even latrines placed where effluents reach =
>the shallow, low-trophic (phyto- and zoo-plankton producing) =
>areas of fish ponds. =
>>Lloyd Prentice wrote:
>>I have read that some of these systems are implicated in the =
>>evolution of influenza viruses. Anybody know more?
I suspect, without knowing many specifics, that your point raises a valid=
health concern, Lloyd. In fact, influenza might be only one of the
possibilities arising from careless handling of fish raised in direct
contact with human and animal manures. E. coli, cholera, salmonella, etc.=
come to mind... thorough cooking would be a necessity in these situations=
,
as it is with chicken 'manufactured' in the US.
One of my two major points was the desirability of careful use/reuse of a=
ll
'waste' products -- which can be seen as either resources or pollution.
When we treat manure as pollution, we pay to have it 'removed' (to where?=
).
Wastes treated as pollution tend to accumulate and, in fact, begin to act=
as pollutants. When we call a waste a resource, we are often able to find=
productive uses. The material may be the same in either case, but our
perception by itself can change that material from a liability to a
valuable resource -- or vice versa.
The other point is that, each time we move a step up the trophic/food
ladder, a great deal of energy is used. Food-to-meat conversion factors
tend to be 20% at the best and are usually much lower (fish are very
efficeint at food conversion, happily). We will always get the biggest
'bang for our buck' if we feed at the lowest point on the trophic ladder
that we can. In general terms, feeding high-protein food to catfish (whic=
h
are scavengers), for instance, is for this reason not 'economical' when
viewed in holistic or ecological terms. Intensive feeding in aquaculture =
or
agriculture raises production dramatically, but it does not necessarily
raise cost-effectiveness of an overall operation due to the law of
diminishing returns (land and materials costs, of course, force productio=
n
to reach toward the highest compromise between intensive production and
least input, fueling some degree of energetic inefficiency in return for
financial viability).
Feeding at the lowest trophic level is why ponds are most-economically
fertilized with calcium and phosphorous... these are critical elements in=
the production of phytoplanktons and zooplanktons, which form the base of=
the food 'pyramid' in aquatic systems (economically important herbivorous=
fish being fairly uncommon -- unless we call phytoplankton eaters
herbivores). Manures are rich in phosphorous, and often rich in calcium. =
A
great deal of production can come from feeding manures to the planktons,
whereas few of the animals higher on the trophic ladder will eat manure t=
o
advantage (a valid fact pointed toward by Lloyd). Manures are ubiquitous
and generally more common than natural sources of high-analysis nutritive=
minerals.
However, manures are an energetic step up from minerals and are also rich=
in nitrogen, which is almost never a limiting factor in fish production a=
nd
is often a harmful pollutant causing turbidity and lowering of dissolved
oxygen levels. Perhaps manures are best 'composting' during biogas
(methane) production and then used as fertilizers in terrestrial
applications. Conventional sewage treatment produces biogas... the
difference is that the methane is seen as pollution an is not captured fo=
r
use (an electrical generation plant in Stanton, CA uses human sewage to
produce the gas which fires its generators). Manures can in fact be
safely-recylced in a number of ways which use their nutritive value to
postive effect instead of purposely dissipating it at considerable expens=
e.
Producing our needs at the lowest economic, energetic and ecological cost=
s
is the critical next step in aquacultural and agricultural systems (as in=
other systems). We'll continue to learn more efficient ways of, as Paula
put it, "...raising fish and plants in a synergistic system... to produce=
products we could consume and sell as "safe", while using a more natural
method of fertilization...". In the process, we'll have to explore many
ideas and look at our energy and materials cycles in a new light.
Eventually we will come up with ways to produce our needs without relying=
on fossil fuels to power the necessary cycles, and without creating
pollution from materials which could be used productively instead. As one=
definition of sustainability puts it, "Sustainability is meeting our need=
s
without endangering the ability of future generations to meet THEIR needs=
".
A worthy goal we're all in agreement with. =
Jack Rowe
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| Message 2 |
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Subject: Re: economics/sustainability of production
From: Jack Rowe
Date: Fri, 12 Dec 1997 11:36:51 -0500
Thank you for the nice comment, Ben.
Well, seems integrating science and sanity is the next step in our
evolution, so we might as well get to it!
Thanks again,
Jack
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| Message 3 |
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Subject: Re: Re: economics/sustainability of production
From: YankeePerm
Date: Fri, 12 Dec 1997 15:22:49 EST
In a message dated 12/12/97 2:14:54 PM, H.Doelle@mailbox.uq.edu.au wrote:
>
>The above is only save AFTER anaerobic treatment of the waste. That is the
practice
>we introduce now in the Pacific, how it is increasingly used in China . We
can
>reduce infectious diseases significantly if we use common sense and stop
knocking
>the production of biogas, which actually could provide all the energy for
your
>fish farming.
>
>Horst Doelle
It is my understanding that there are 15 million methane (biogas) digesters
operating in China. The Chinese are nothing, if not practical. However
methane digesters only work where there is an adequate concentration of manure
and/or other organic material making up a suitable C/N ratio. The manure a
nuclear family produces, for example, wouldn't produce enough methane to boil
their breakfast eggs. Cattle in confinement, or on a larger scale pigs and
poultry, produce adequate amounts, but confinement systems are often
profoundly inappropriate both in terms of resource utilization and in terms of
respect for the conditions and enjoyment of life of the animals.
All this is by way of saying that there are many models. Methane digesters
are great in many conditions where feedstock is produced at adequate scale.
They are particularly useful in tropical and subtropical areas for health
reasons unrelated to aquaculture as one stage in treatment of human wastes.
This brings to mind some claimes I have heard John Todd make about raising
striped bass and other fish in seweage treatment waters. I'd like to hear
from someone on the list who may be more familiar with what John had in mind
than am I.
For Mother Earth, Dan Hemenway, Yankee Permaculture Publications (since 1982),
Elfin Permaculture workshops, lectures, Permaculture Design Courses,
consulting and permaculture designs (since 1981), and now correspondence
courses via email. One is now underway. Next Live program: Paraguay,
8/10-22/98. Internships available. Copyright, 1997, Dan & Cynthia Hemenway,
P.O. Box 52, Sparr FL 32192 USA YankeePerm
We don't have time to rush.
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| Message 4 |
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Subject: Re: Re: economics/sustainability of production
From: "H.Doelle"
Date: Sat, 13 Dec 1997 09:56:56 +1100
Of course, you have to have a certain C/N ratio, which is always present in
human or animal waste.
The Chinese have mainly small digesters feeding small nuclear families. A
family of four can easily get enough biogas from 2-3 cows plus their own
family to boil even more than a couple of eggs for breakfast.
I always emphasized that energy production depends on the region and
availability of resources. Biogas is not only for tropical rural countries.
We also have sewerage plants in our developed country cities and can use the
biogas.
Anaerobic digestion of manure is the only way of killing pathogens and not
risking diseases. Manure can not be properly *composted* to free it from
disease causing microbes. The effluent or solids from an anaerobic digester
can safely be used for composting.
If you do not believe this, make a test for E.coli and you will find out
very easily yourself.
Cheers
Horst Doelle
At 03:22 PM 12/12/97 EST, you wrote:
>
>In a message dated 12/12/97 2:14:54 PM, H.Doelle@mailbox.uq.edu.au wrote:
>
>>
>>The above is only save AFTER anaerobic treatment of the waste. That is the
>practice
>>we introduce now in the Pacific, how it is increasingly used in China . We
>can
>>reduce infectious diseases significantly if we use common sense and stop
>knocking
>>the production of biogas, which actually could provide all the energy for
>your
>>fish farming.
>>
>>Horst Doelle
>
>It is my understanding that there are 15 million methane (biogas) digesters
>operating in China. The Chinese are nothing, if not practical. However
>methane digesters only work where there is an adequate concentration of manure
>and/or other organic material making up a suitable C/N ratio. The manure a
>nuclear family produces, for example, wouldn't produce enough methane to boil
>their breakfast eggs. Cattle in confinement, or on a larger scale pigs and
>poultry, produce adequate amounts, but confinement systems are often
>profoundly inappropriate both in terms of resource utilization and in terms of
>respect for the conditions and enjoyment of life of the animals.
>
>All this is by way of saying that there are many models. Methane digesters
>are great in many conditions where feedstock is produced at adequate scale.
>They are particularly useful in tropical and subtropical areas for health
>reasons unrelated to aquaculture as one stage in treatment of human wastes.
>
>This brings to mind some claimes I have heard John Todd make about raising
>striped bass and other fish in seweage treatment waters. I'd like to hear
>from someone on the list who may be more familiar with what John had in mind
>than am I.
>
>For Mother Earth, Dan Hemenway, Yankee Permaculture Publications (since 1982),
>Elfin Permaculture workshops, lectures, Permaculture Design Courses,
>consulting and permaculture designs (since 1981), and now correspondence
>courses via email. One is now underway. Next Live program: Paraguay,
>8/10-22/98. Internships available. Copyright, 1997, Dan & Cynthia Hemenway,
>P.O. Box 52, Sparr FL 32192 USA YankeePerm
>
>We don't have time to rush.
>
>
Horst W.Doelle,D.Sc.
Director, MIRCEN-Biotechnology Brisbane
Chairman, IOBB
Hon.Member of Depts. Microbiology & Chemical Engineering
FAX: +617-38783230
Email: H.Doelle@mailbox.uq.edu.au
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| Message 5 |
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Subject: Re: economics/sustainability of production
From: "H.Doelle"
Date: Sat, 13 Dec 1997 10:00:38 +1100
I certainly vote for your statement below
Horst Doelle
At 11:36 AM 12/12/97 -0500, you wrote:
>Thank you for the nice comment, Ben.
>
>Well, seems integrating science and sanity is the next step in our
>evolution, so we might as well get to it!
>
>Thanks again,
>
>Jack
>
>
Horst W.Doelle,D.Sc.
Director, MIRCEN-Biotechnology Brisbane
Chairman, IOBB
Hon.Member of Depts. Microbiology & Chemical Engineering
FAX: +617-38783230
Email: H.Doelle@mailbox.uq.edu.au
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| Message 6 |
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Subject: Re: Adaptable Systems - was economics/sustainability of production
From: JCurts2318
Date: Fri, 12 Dec 1997 20:43:41 EST
In a message dated 97-12-12 11:38:41 EST, you write:
> Don't want to tie up the list only discussing our methods, but would be
> happy to discuss further if you want.
>
> We've found also that the list is beneficial. But then, we've always said
> we benefit a great deal from questions - that's what starts the search
going
> isn't it?
>
> Paula
Please feel free to use all the list time you like. We appreciate all that you
share with us. Much of what you pass on is applicable to other systems as
well.
Thank you
Jim
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