Plastic Tube Digesters in Kenya - Revision history

Wiki Gardener at 11:25, 18 February 2015

2015-02-18T11:25:01Z

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Ranisha: /* Survey Reports */

2014-11-05T13:06:58Z

‎Survey Reports

Ranisha: /* Survey Reports */

2014-11-05T13:05:11Z

‎Survey Reports

Ranisha: /* The Technology */

2014-11-05T12:55:43Z

‎The Technology

Ranisha at 12:38, 5 November 2014

2014-11-05T12:38:38Z

Ranisha at 14:01, 17 July 2014

2014-07-17T14:01:11Z

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Wiki Gardener at 14:55, 8 July 2013

2013-07-08T14:55:07Z

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Robert at 10:58, 1 April 2011

2011-04-01T10:58:38Z

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Julia Harter at 11:29, 31 March 2011

2011-03-31T11:29:36Z

Julia Harter at 11:26, 31 March 2011

2011-03-31T11:26:14Z

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@@ Line 57: / Line 57: @@
 <br/>
@@ Line 62: / Line 63: @@
 *Ochieng, Francis Xavier (2010): "Survey of Plastic Tube Digesters in Kenya - A Field Assessment Survey of the Performance of Plastic Tube Digesters in Kenya." Prepared for: Regional Energy Advisory Platform (East Africa) - REAP (GIZ). [[:File:Ochieng, Francis Xavier - 2010 - Survey Report on Plastic Tube Digesters in Kenya.pdf|click here]]<br/>
-*Matiri, F. M. and Kiruiro, E.M (2010): "The Impacts of Plastic Tube Digester (PTD) Technology at the Household Level/ A Case Study of Central Kenya Highlands". [http://www.kari.org/biennialconference/conference12/docs/THE_IMPACTS_OF_PLASTIC_TUBE_DIGESTER_(PTD)_TECHNOLOGY_AT_THE_HOUSEHOLD_LEVEL.pdf THE IMPACTS OF PLASTIC TUBE DIGESTER (PTD) TECHNOLOGY AT THE  HOUSEHOLD LEVEL: A CASE STUDY OF CENTRAL KENYA HIGHLANDS]
+*Matiri, F. M. and Kiruiro, E.M (2010): "The Impacts of Plastic Tube Digester (PTD) Technology at the Household Level/ A Case Study of Central Kenya Highlands". [http://bit.ly/1tbH780 THE IMPACTS OF PLASTIC TUBE DIGESTER (PTD) TECHNOLOGY AT THE HOUSEHOLD LEVEL: A CASE STUDY OF CENTRAL KENYA HIGHLANDS]
 <br/>

@@ Line 57: / Line 57: @@
 <br/>
 = Survey Reports =
-*Ochieng, Francis Xavier (2010): "Survey of Plastic Tube Digesters in Kenya - A Field Assessment Survey of the Performance of Plastic Tube Digesters in Kenya." Prepared for: Regional Energy Advisory Platform (East Africa) - REAP (GIZ). [[:File:Ochieng,_Francis_Xavier_-_2010_-_Survey_Report_on_Plastic_Tube_Digesters_in_Kenya.pdf|click here]]<br/>
+*Ochieng, Francis Xavier (2010): "Survey of Plastic Tube Digesters in Kenya - A Field Assessment Survey of the Performance of Plastic Tube Digesters in Kenya." Prepared for: Regional Energy Advisory Platform (East Africa) - REAP (GIZ). [[:File:Ochieng, Francis Xavier - 2010 - Survey Report on Plastic Tube Digesters in Kenya.pdf|click here]]<br/>
-*Matiri, F. M. and Kiruiro, E.M (2010): "The Impacts of Plastic Tube Digester (PTD) Technology at the Household Level/ A Case Study of Central Kenya Highlands". [http://www.kari.org/biennialconference/conference12/docs/THE IMPACTS OF PLASTIC TUBE DIGESTER (PTD) TECHNOLOGY AT THE HOUSEHOLD LEVEL.pdf http://www.kari.org/biennialconference/conference12/docs/THE IMPACTS OF PLASTIC TUBE DIGESTER (PTD) TECHNOLOGY AT THE HOUSEHOLD LEVEL.pdf]
+*Matiri, F. M. and Kiruiro, E.M (2010): "The Impacts of Plastic Tube Digester (PTD) Technology at the Household Level/ A Case Study of Central Kenya Highlands". [http://www.kari.org/biennialconference/conference12/docs/THE_IMPACTS_OF_PLASTIC_TUBE_DIGESTER_(PTD)_TECHNOLOGY_AT_THE_HOUSEHOLD_LEVEL.pdf THE IMPACTS OF PLASTIC TUBE DIGESTER (PTD) TECHNOLOGY AT THE  HOUSEHOLD LEVEL: A CASE STUDY OF CENTRAL KENYA HIGHLANDS]
 <br/>
 = Further Information =

@@ Line 33: / Line 33: @@
 = The Technology =
-<span style="color: black; line-height: 150%">In 2002, the first generation of plastic tube digester was basically made out of two Polythene layers. The latest generation PTD was developed by Pioneer and is sold by the other companies as well. The digester bag material is composed of a double layer; 300 micron UV treated Polythene reinforced with fiberglass. The thickness and the UV treatment increased the digesters' potential lifespan, which according to the supplier is estimated to be up to 15 years. The companies are distributing two digester sizes of 6 and 16 m</span><sup>3</sup><span style="color: black; line-height: 150%">, costing about $500 and $800 respectively. This includes the stove, gas pipes, installation, as well as transportation to most parts of Kenya but excludes the cost of digging the trench.</span> <!--[if gte vml 1]><o:wrapblock><v:shapetype
+<span style="color: black; line-height: 150%">In 2002, the first generation of plastic tube digester was basically made out of two Polythene layers. The latest generation PTD was developed by Pioneer and is sold by the other companies as well. The digester bag material is composed of a double layer; 300 micron UV treated Polythene reinforced with fiberglass. The thickness and the UV treatment increased the digesters' potential lifespan, which according to the supplier is estimated to be up to 15 years. The companies are distributing two digester sizes of 6 and 16 m</span><sup>3</sup><span style="color: black; line-height: 150%">, costing about $500 and $800 respectively. This includes the stove, gas pipes, installation, as well as transportation to most parts of Kenya but excludes the cost of digging the trench.</span>
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+<gallery>
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+File:Img 4234.jpg|Un-inflated digester bag after installation
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+File:Img 4936.jpg|PTD in use with gas pipe and inlet in the back
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- </v:shape><![endif]--><!--[if !vml]--><span></span><br/>The standard digester can be operated with one to <!--[endif]--><!--[if gte vml 1]></o:wrapblock><![endif]-->two dairy cows (local breed: 4 cows), while the large one requires about two cows (local breed: 5 cows). Matiri and Kiruiro found an average of three<span style="line-height: 150%">zero-grazing</span><span style="color: black; line-height: 150%">animals per biogas household</span>.<br/>
 = PTD Performance =

@@ Line 1: / Line 1: @@
 Survey into the Use of Plastic Tube Digesters in Kenya (for PTDs in other countries: [[Experience_with_Polyethylene_Biogas_Digester_(PBD)|click here]])<br/>
@@ Line 111: / Line 110: @@
 = Survey Reports =
-*Ochieng, Francis Xavier (2010): "Survey of Plastic Tube Digesters in Kenya - A Field Assessment Survey of the Performance of Plastic Tube Digesters in Kenya." Prepared for: Regional Energy Advisory Platform (East Africa) - REAP (GIZ). [http://energypedia.info/index.php/File:Ochieng,_Francis_Xavier_-_2010_-_Survey_Report_on_Plastic_Tube_Digesters_in_Kenya.pdf click here]<br/>
+*Ochieng, Francis Xavier (2010): "Survey of Plastic Tube Digesters in Kenya - A Field Assessment Survey of the Performance of Plastic Tube Digesters in Kenya." Prepared for: Regional Energy Advisory Platform (East Africa) - REAP (GIZ). [[:File:Ochieng,_Francis_Xavier_-_2010_-_Survey_Report_on_Plastic_Tube_Digesters_in_Kenya.pdf|click here]]<br/>
 *Matiri, F. M. and Kiruiro, E.M (2010): "The Impacts of Plastic Tube Digester (PTD) Technology at the Household Level/ A Case Study of Central Kenya Highlands". [http://www.kari.org/biennialconference/conference12/docs/THE IMPACTS OF PLASTIC TUBE DIGESTER (PTD) TECHNOLOGY AT THE HOUSEHOLD LEVEL.pdf http://www.kari.org/biennialconference/conference12/docs/THE IMPACTS OF PLASTIC TUBE DIGESTER (PTD) TECHNOLOGY AT THE HOUSEHOLD LEVEL.pdf]
@@ Line 125: / Line 124: @@
 <references />
 [[Category:Biogas]]

← Older revision		Revision as of 11:29, 31 March 2011
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	== ''PTD Performance'' ==		== ''PTD Performance'' ==
−
−	~~<span style="line-height: 150%; color: black;" />~~

	Findings indicate that most of the users are quite satisfied with their PTD. The GIZ authorized survey covered 35 digesters; another 4 were discovered to be decommissioned for various reasons. It found that out of these, 29 (or about 80%) were in good working condition. Six digesters were not operating, because either the digester (four households) burst after animals/children stepped on it or in another case the pipe to the stove was disconnected. The remaining digester was out of use due to a thick layer of scum that drastically reduced its gas production. Matiri and Kiruiro found in their survey even better results as all 60 digesters visited were in use.<br>Both studies confirm: PTD users receive similar benefits as the ones provided by masonry digesters. Households use less charcoal and firewood and therefore save time (especially for women) and money. Most digesters produce enough gas to cook nearly all of the family’s meals (about five hours per day). Owners also mentioned improvements in sanitation and air quality due to the better disposal of dung. <br>Three central problems specifically related to the PTD technology itself can be identified: insufficient gas production, low gas pressure and the vulnerability of the digester bag. The first two issues are connected. Temperature variations inside the digester lead to low gas production and pressure in the morning and evening hours. Many households place some weight on top of the digester bag to increase gas pressure. The usage of a gas storage bag, as practiced in the South American GIZ EnDev program, is also an inexpensive way to store more gas and increase pressure. The low gas pressure does not allow the use of a biogas lamp but with the now available Solar LED lights, this should no longer be an issue. <br>The main reason for households to abandon their PTD is the digester bag’s vulnerability to piercing or bursting. In order to avoid this, the usage of a fence is recommended. One owner had fixed the bag with a bicycle repair kit. <br>Further research is necessary regarding the optimization of the retention time and the stabilization of the temperature.		Findings indicate that most of the users are quite satisfied with their PTD. The GIZ authorized survey covered 35 digesters; another 4 were discovered to be decommissioned for various reasons. It found that out of these, 29 (or about 80%) were in good working condition. Six digesters were not operating, because either the digester (four households) burst after animals/children stepped on it or in another case the pipe to the stove was disconnected. The remaining digester was out of use due to a thick layer of scum that drastically reduced its gas production. Matiri and Kiruiro found in their survey even better results as all 60 digesters visited were in use.<br>Both studies confirm: PTD users receive similar benefits as the ones provided by masonry digesters. Households use less charcoal and firewood and therefore save time (especially for women) and money. Most digesters produce enough gas to cook nearly all of the family’s meals (about five hours per day). Owners also mentioned improvements in sanitation and air quality due to the better disposal of dung. <br>Three central problems specifically related to the PTD technology itself can be identified: insufficient gas production, low gas pressure and the vulnerability of the digester bag. The first two issues are connected. Temperature variations inside the digester lead to low gas production and pressure in the morning and evening hours. Many households place some weight on top of the digester bag to increase gas pressure. The usage of a gas storage bag, as practiced in the South American GIZ EnDev program, is also an inexpensive way to store more gas and increase pressure. The low gas pressure does not allow the use of a biogas lamp but with the now available Solar LED lights, this should no longer be an issue. <br>The main reason for households to abandon their PTD is the digester bag’s vulnerability to piercing or bursting. In order to avoid this, the usage of a fence is recommended. One owner had fixed the bag with a bicycle repair kit. <br>Further research is necessary regarding the optimization of the retention time and the stabilization of the temperature.