[Digestion] Biogas plant at Zoo

Murali Krishna bmkrishna6 at gmail.com
Mon Jul 1 02:56:57 CDT 2013


Good day Dr. Karve,

All of us are well aware that soil is most precious and it should be
protected. There should be humus in the soil to bind soil particles and it
increases soil aggregation and aggregate stability, increases the Cation
Exchange Capacity and it is a large source of minerals and other
nutrients.  Undoubtedly we should recycle carbonaceous  material and it
should go into the soil. Decomposition of carbonaceous material results in
the formation of humus. Humus affects soil properties.

You would please appreciate that soils in tropical countries are depleting
very fast and eroding.  This is more particularly true with the low organic
carbon soils. Let us not forget  the well said saying "A Nation that
destroys its soil destroys itself".

I am quite surprised and and the same time pleased that addition of  100
kgs of sugar and 375 kgs of green leaves per hectare per annum is giving
good results.  Does this enough to supplement the reserves that are  drawn
crop by crop from the richest soils.  Can we sustain with this unending
withdrawals?  There is enough organic matter to recycle and there is no
shortage. What we take from the Mother Nature, we should  give back...then
only the man kind survives.

Best Regards,

Krishna.






On Sun, Jun 30, 2013 at 8:41 AM, Anand Karve <adkarve at gmail.com> wrote:

> Dear Mr. Eaton,
> one can very easily dry dung, at least in a semi-arid country like India,
> by just exposing it to sunlight. For greater output, one can use a filter
> press, as is used in a sugar factory to separate fine particles of bagasse
> from sugarcane juice. Dung cakes is a source of income to villagers. 40 kg
> dung, which is required daily as input in a family size biogas plant,
> yields dung cakes that can be sold in India for about US$1. It requires
> daily only about 2 to 3 kg of cotton stalks to cook the the daily meals for
> a family of 5, if it uses an improved stove based on the rocket or TLUD
> principle. Woody agricultural waste like stalks of cotton and pigeonpea, or
> shanks of maize are readily available to rural people. They are not a
> saleable commodity, and therefore they are available free of cost. *B*ecause
> of the reason that dung cakes are a saleable commodity, people in
> Indian rural areas have refused to use biogas plants based on dung. In
> spite of all the propaganda by Government of India and a subsidy of 20% on
> the cost of construction, less than 2% of the Indian rural population
> has working dung based biogas plants.
>          I agree with your view that a biogas plant in a zoo would
> eliminate the waste and would also have educative value. But the education
> should be all-inclusive and not one-sided. For instance, it should be
> taught to the public that making biogas from dung is a wasteful process.
> 1kg dry dung would give about 3500 to 4000 kcal/kg if burned directly,
> whereas the same quantity of dung would yield only 600 kcal/kg if it is
> converted into biogas. They should also be told the truth about the
> virtues of biogas slurry as fertilizer.  In organic agriculture, the plants
> get the major part of their minerals from the soil itself, and not from the
> decomposed organic matter. The organic matter is used up mainly by the soil
> micro-organisms to multiply their numbers. It is an accepted fact that
> the number of microbes in the soil is directly correlated to soil
> fertility. Therefore the aim of organic farming should be to increase the
> number of microbes in the soil, and therefore a farmer should apply high
> calorie, non-composted organic material to the soil. If one were to provide
> all the plant nutrients to one's crop through compost, one would require 50
> ton compost per ha per crop. There are literally thousands of farmers
> in Maharashtra State, India, who apply only about 25 kg sugar or 125 kg
> green leaves per ha, once every three months, to their field, and get very
> high yields.     Yours
> A.D.Karve
>
> On Fri, Jun 28, 2013 at 8:28 AM, Alexander Eaton <alex at sistemabiobolsa.com
> > wrote:
>
>> Dr. Karve,
>>
>> You have held this stance in many past posts, comparing starch to waste,
>> and arguing waste as not an ideal feedstock for AD.  I have always thought
>> that your point is valid, but a bit academic and missing the fact that AD
>> systems can be seen as an extension of the animal digestive system,
>> treating waste further and extracting energy that has not been used.
>>  Clearly starch creates more gas, but the questions posed here is not about
>> choosing starch or animal dung for a digester, it is about whether a zoo
>> would be wise to consider a digester to treat animal waste and recover
>> energy.  Is dedicating space and time at a zoo to dehydrating animal dung
>> and then developing a system to burn it and recover the energy really a
>> better alternative than an AD system?  From an energy and process balance,
>> can you explain a system that would perform better than a digester in this
>> context?
>>
>> Best,
>>
>> A
>>
>>
>>
>>
>>
>>
>
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> for more information about digestion, see
> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> and the Biogas Wiki http://biogas.wikispaces.com/
>
>
>


-- 
Regards.

Murali Krishna
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* **Never put water down the drain when there may be another use for it*
*Save the Environment*

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