[Digestion] Introduction to Pay As You Go Biogas and a Strange biogas startup problem

Wed Sep 18 08:34:53 CDT 2013

Kyle,

If the meter shuts off, where does the gas go?  I am assuming it must
eventually be released as raw methane.  Please explain how you deal with
that situation.  Also, pay-as-you-go in this sense seems to disincentive
productive gas use in poor population; the better the digester is working
the more expensive it is per month, independent of gas need or utility.
 Rather than being put to productive use, excess gas above the basics needs
of a user is then released into the atmosphere.  Someone with no money
might be temped to sabotage the digester to avoid further payment, and the
bad smell that raw biogas has if it is released.

If these same users were just given an accessible fixed payment, low
interest loan, they would be incentivized to maximize gas production.
 Production above their basic needs could then be employed as a low-cost
input for other activities.  This same issue happened on a large scale in
Mexico, where farmers were given digesters as carbon offset projects, but
not properly incentivized to use them.  When economic benefit are not
coupled with good management of the system, there are going to be higher
failure rates.

Can you provide more details about the scheme, maybe the pricing, that may
negate this impact?

We try not to start systems during the coldest two months, but if we do, we
reduce the initial input of cow manure and focus more on effluent from
digesters that are operating nearby, with bacteria that have adjusted to
the colder season.  Start up for us can take up to 60 days for flammable
gas.  If your chamber become acidified you almost need to start over.  We
try to dilute the systems heavily, remove the acidified material, and add
as much digester effluent as possible.

Best,

Alex

On Wed, Sep 18, 2013 at 5:46 AM, David <davidf at kingdombio.com> wrote:

>  Kyle, Hello,
>
> The meter system looks very interesting. How much does it add to the cost
> of a biogas system?
>
> Are you using above ground plastic tank plant, as shown in the website? If
> so, the gas production will be strongly affected by air temperature. Once
> the slurry temperature drops below about 25 deg.C, digestion will take a
> long time to get started. It is possible that the acid formers will be
> generating volatile fatty acids faster than the methanogens can work, so
> the plant goes acid (and smells bad). Have you measured the slurry
> temperatures of the plants that do not work well?
>
> Methanogens take a long time to grow, especially at lower temperatures.
> There is also the issue of temperature shock. When the dung is dumped by
> the cow in a cold place (less than 25 deg.C), the temperature drops (from
> the temperature inside the cow of about 37 deg.C). Methanogens are affected
> by a temperature drop of less than 5 deg.C in one day. They do not die, but
> go into a quiescent state and take time to start again, especially if the
> temperature remains low.
>
> Best wishes,
> David
> *davidf at kingdombio.com* <davidf at kingdombio.com>
>
>  ******************************************************
> Dr David Fulford CEnv MEI, 15, Brandon Ave, Woodley, Reading RG5 4PU
>        Tel: +44(0)118 326 9779 Mob: +44(0)7746 806401
> Kingdom Bioenergy Ltd, *www.kingdombio.com* <http://www.kingdombio.com>, *
> davidf at kindombio.com* <davidf at kindombio.com>
>                                 Skype Identity: djfulford
>
>
>
> ------ Original Message ------
> From: "Kyle Schutter" <kyle at takamotobiogas.com>
> To: Digestion at bioenergylists.org
> Sent: 18/09/2013 09:35:39
> Subject: [Digestion] Introduction to Pay As You Go Biogas and a Strange
> biogas startup problem
>
> Hi All,
>
> I would like to introduce our business to you all that we have been
> working on for the last 12 months.
>
> We have developed a Pay As You Go biogas meter that charges clients for
> gas as they use it, instead of a single high upfront cost of purchasing a
> whole biogas system. Our clients pay by mobile money and when they run out
> of credit the meter automatically shuts off. Our system also communicates
> to us by GSM on the status of the system (if there is any leak, pH of the
> system, pressure, etc) every day by text message. See a diagram of how this
> works here
> http://www.takamotobiogas.com/takamoto-pay-as-you-go-biogas-50-unit-pilot-is-a-success/ I
> look forward to getting your feedback.
>
>  We have 70 systems installed in the last 4 months using our Pay as you
> go meter which is a huge success for us. However, we are having a seemingly
> unrelated problem with system startup and I would love to get your advice
> on how I figure out what is going wrong.
>
> When we install a biogas system we fill it with dung and water and for
> systems installed in the last month we have added 5% of the total volume as
> innoculant from a biogas systems that is working well. We have made sure
> that the cow dung is not from cows that have received antibiotics and the
> cow stalls haven't been sprayed with dissinfectant. For the first 30
> systems we installed, there was no problem startingup; the first 30
> required no innoculant and started producing flammable biogas in 3 days.
> But since then, especially during the rainy and cold season, digesters have
> not started up reliably. I would say that more than 50% took more than a
> month to work efficiently and at least three systems had their pH drop so
> low (around pH 6.0) that we decided to replace the cow dung. For the
> systems that are not starting up very well, we add 200 kg of innoculant
> every week until it starts working. I tested the water that our clients use
> to mix with the cow dung and found that it was rather acidic (pH 5 to pH7)
> but this was true of clients whose systems were working too, so the acidity
> of the water can't be the only problem.
>
> The symtoms we are seeing are as follow:
> -The pH is below 7 (but not less than 6.5)
> -Some gas is usually produced but it is not flammable and usually smells
> very bad (lots of hydrogen sulfide)
>
> It seems that there could be several possibilities here:
> 1. There is a breakdown of the biological pathway. Either we are missing
> some bacteria or there is some inhibitor.
> 2. There are a combination or problems involving cold temperature, rain
> water and low pH mixing water (though we are still having a problem after
> the cold rainy season).
> 3.There is some toxic substance in our tanks or the cow dung that is
> causing the problem.
>
> I look forward to your feedback on both the new meter and on the startup
> problem we are having.
>
> Best wishes,
>   Kyle
> Founder and Director of Technology
> Schutter Energy Ltd.
> +254 703113383
> kyleschutter (skype)
> www.takamotobiogas.com
>
>
>
>
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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/
>
>
>

-- 
Alexander Eaton
Sistema Biobolsa
IRRI-Mexico
RedBioLAC

Mex cel: (55) 11522786
US cel: 970 275 4505

alex at irrimexico.org
alex at sistemabiobolsa.com

sistemabiobolsa.com
www.irrimexico.org
www.redbiolac.org
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