[Digestion] slurry from Potassium hydroxide catalyzed glycerin

[Anand Karve]

Dear Douglas,
there are many economically useful plants that tolerate about 4% saliniy in
the root zone. I can only name the tropical ones. They are coconut,
casuarina (timber), Thespesia populnea ((timber), Salvadora oleoides
(oilseed), a number of mangrove species (timber, firewood), many plants
belonging to the family chenopodiaceae (leafy vegetables), etc. If you used
salt water for irrigation in a normal field, the water evaporates and the
salt accumulates in the soil. The increased salinity ultimately kills the
plants. But if these plants are planted in raised beds offering good
drainage of water, the excess salt is washed away with every irrigation and
the plants survive. I have demonstrated that these plants can even be
irrigated with untreated seawater. One uses so much sea water for
irrigation, that a part of it drains out of the beds and flows back into
the sea.
Yours
A.D.Karve



On Thu, Jan 5, 2012 at 8:02 AM, David <david at h4c.org> wrote:

>
> Douglas,
>
> On 1/4/2012 7:15 AM, Douglas Renk wrote:
>
>  Has anyone demonstrated the effect of introducing marine anaerobes
> highly toleratant of sodium into glycerin by-product enhanced
> digesters? Sodium may still be of concern for land application, but perhaps
> the digester could remain stable. I recall some studies about 20 years ago
> with Chynoweth at IGT for inoculum suited for sea kelp digestion.
>
> Any experience with this may greatly help our biogas industry
> with co-digestion of biodiesel glycerin. I find the industry resistant to
> move away from sodium hydroxide catalyst.
>
>
> In a study about the digestion of (apparently salty) Korean food wastes
> ("Effect of particle size and sodium ion concentration on anaerobic
> thermophilic food waste digestion" Water Sci Technol. 2000;41(3):67-73),
> Kim et al found that
>
> ...methane gas production [was] affected by various sodium ion
> concentrations. The reaction was not affected until 5 g/L of sodium ion was
> added into the test reactor. The volume of methane gas produced from the
> test reactors decreased gradually according to the sodium ion
> concentrations applied when more than 5 g/L of sodium ion. In case of 20
> g/L of sodium ion, the methane gas production was reduced to about 50% of
> theoretical gas volume.
>
>
> Of course, as you imply, a good deal depends on the population in the
> digester, but given that glycerin is so easily acidified, that it is more
> easily produces stable digestion when other materials are added to the
> digester, and that it must in any case be fed slowly, it seems unlikely
> that the first problem one would encounter would be sodium ion
> concentration. In other words the circumstances that lead to stable
> digestion would tend likewise to reduce sodium concentration in the
> digester, except perhaps if it is fed kelp or a similar high-sodium
> co-digestate. As far as Wayne's question about ag use of sodium-"enriched"
> effluent, that I would think would depend primarily on the circumstances.
> Sodium would be a problem particularly in drier climates and soils.
>
>
> 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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>
>


-- 
***
Dr. A.D. Karve
Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)
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