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

[David]

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

******************************************************
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, 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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