Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE)
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Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE) 03 Mar 2013 09:01 #3694

  • robhughes
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Dear all,
I would like to introduce to you a research grant with funding from the Bill & Melinda Gates Foundation which I am leading:

Title of grant: Energy recovery & waste treatment with floating biodigesters
Subtitle (more descriptive title): Innovative floating and small scale biodigesters for human and animal waste treatment, gas production, and agricultural application in floating and flood-affected areas.

Name of lead organization: Live & Learn Environmental Education
Primary contact at lead organization: Robert Hughes
Grantee location: Phnom Penh, Cambodia
Developing country where the research is being tested: Cambodia.

Short description of the project: This project will develop and trial floating and small-scale biodigesters to convert human and animal waste to biogas for energy and treated waste for fertilizer, while improving the sanitation and public health outcomes of communities living in challenging environments such as water-based and floodprone communities.

Goal(s): To develop and make available new low cost biodigesters appropriate for application in challenging environments, where access to sanitation and energy is severely limited. To demonstrate the potential to improve public health, water quality, sanitation, natural resource protection, energy access, and livelihoods in vulnerable communities.

Objectives: 1) Develop, test, improve and document small scale and floating biodigesters and required supporting systems (flotation, inlet systems etc) to allow effective operation in floating and flood-affected villages. 2) Collect supporting data on operational performance under controlled conditions 3) Conduct preliminary practical field trials for community uptake and acceptance feedback and evidence. 4) Integrate biodigesters into holistic development programs especially for sanitation, health,

Start and end date: November 2011 - October 2013
Grant type: Grand Challenge Exploration (GCE) Round 7
Funding for this research currently ongoing: yes
Research or implementation partners: Live & Learn Environmental Education, Engineers Without Borders Australia, Royal University of Agriculture (Cambodia), Lund University (Sweden), Communities of the Tonle Sap Lake Cambodia

Contacts, links, further readings:
Documents in SuSanA library:
susana.org/lang-en/library?view=ccbktype...p;type=2&id=1768

Video about the project:



Website:
livelearn.org/projects/floating-bio-dige...bio-digester-project
www.facebook.com/floatinglatrine

Key components:
Research is covering 4 main areas: a) waste treatment effectiveness and related parameters, b) biodigestion operation and gas production c) system physical performance and material requirements, d) community acceptance evidence.

Bear in mind the project is still in progress so we plan to complete and upload more work later. We don't have a lot of results publishable yet, but some background info is attached below (scrol to the end of this post).

So, what do you think about this research project and its relevance? I am happy to answer any questions you may have.

Regards,
Rob

++++++++++++++++++++
P.S. Oh, and here is some more information about our work with the floating communities on Tonle Sap lake in general if you are interested:

I think our work is really working in a difficult and often neglected space so we always aim to encourage more awareness and action in these areas, and especially in innovation technologies and approaches that can help change the playing field a bit.

Some of the innovative technologies are fairly new - the communities may be a little bit familiar with the concepts, but often they do not exist in their community yet. In the flood-affected areas some of the technologies exist but are not well adapted to the flooding, while in floating villages they do not exist at all. Biodigesters, for example, have some limited use and understanding in flood-affected areas, but in floating communities they are completely new. Toilets exist in flood-affected areas but can fail during flooding, while they are non-existent in floating communities. The agricultural techniques mostly build on basic experiences already utilised but are targeted at extending and improving agriculture - for example floating and raised gardens that can extend the growing seasons into the wet season.

Introductory activities comprised several key approaches: Generally we have taken a participatory approach to technical development so the innovations are suited to the communities and developed with their help. Then for introduction of the solutions we used initial workshops and focus groups, then establishment of demonstration systems, sites, and gardens as good examples, then capacity building of community volunteers including Field Facilitators and Farmer Collaborators to be focus points and disseminate to the community. In Cambodia, 'seeing is believing' and real life practice and examples that people can see are much more effective, while little attention is paid to theory and words.

For selection of crops for floating gardens, we conducted desktop research and focus groups on different crop requirements as well as value to identify potential crops, then these were tested in trial gardens on demonstration sites.
We're really interested in the links between sanitation and agriculture, and resource recovery. There are a lot of chickens, dogs etc that are too difficult to collect much waste, however pigs, cows, and buffalos are the most suitable for use in biodigesters. In floating communities there are an increasing number of floating pig farms that are impacting water quality so that is a major focus of floating biodigester applications. We are also utilising waste from fish processing in the biodigesters which is readily available.

In general, our approach is to demonstrate that even in the most challenging situations (environmentally, economically, culturally etc), there are solutions that can have multiple benefits for livelihoods, sanitation, nutrition, energy, and environmental protection. A holistic approach with some targeted innovations can overcome some of the major challenges for some of the most vulnerable and neglected communities. In particular, sanitation is non-existent in floating villages (of which there are millions of inhabitants around the world), and has typically been put in the 'too hard basket'. This is the challenge we aim to overcome.

Some more information is at the links below:

Floating Toilet Project:
youtu.be/HWFx1stlT6k
livelearn.org/projects/floating-latrine-...oject-ecosan-project

Floating Gardens:
livelearn.org/projects/floating-gardens-project
Case study - designing gender sensitive sanitation for floating villages:
www.inclusivewash.org.au/Literature/Case...ating%20villages.pdf

Case Study Number 2 in this case study collection explains our project with the floating toilets ("Case Study 2: Floating Community Ecological Sanitation Project on the Tonle Sap Lake"):
www.susana.org/docs_ccbk/susana_download...case-studies-1-8.pdf
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Rob Hughes,
WASH Manager,
Live & Learn Environmental Education
Last Edit: 23 May 2013 15:21 by muench.
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Re: Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE) 23 May 2013 12:10 #4473

  • robhughes
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I've attached a recent Masters Thesis on the Environmental Sustainability of Floating Biodigesters on the Tonle Sap.
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Rob Hughes,
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Re: Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE) 23 May 2013 13:25 #4474

  • JKMakowka
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Ahh, interesting.

I recently looked into floating plastic-bag biodigestors as that seemed like a great way to avoid the (apparently in Uganda significant) problems with external damage to the plastic tube which is caused (by anecdotal evidence) through playing children & rodents (and probably other forms of neglect and misuse).
However except for a few short paragraphs and pictures, it was impossible to find good examples of such a design.

Contrary to what you are proposing, it was my idea however to integrate them with aquaculture ponds, with the effluent directly fertilizing the micro-algae growth to feed tilapia.
As a beneficial side-effect the surface of the digester would probably be a good substrate to facilitate the surface growth of the tilapia preferred feed algae (that normally grow on the surface of stones and water plants etc.) and provide shadow and cover against bird predators.

Another interesting design aspect could be that such a floating tube digestor could be manually rotated along its axis to provide for a better mixing of the slurry and thus increased bio-gas production.
Edit: Ah, and the mean temperature of the digestor should be more stable (but a bit lower due to evaporation) also, thus likely resulting in a more consistent digestion especially where there are bigger day/night temperature differences.

Anyways, please keep us updated on the results of this!
Krischan Makowka
Technical Adviser at the Uganda Water and Sanitation NGO Network (UWASNET)
www.uwasnet.org
Last Edit: 23 May 2013 13:44 by JKMakowka.

Re: Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE) 23 May 2013 19:53 #4480

  • gitum
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Dear Rob,

I would like to ask you couple of questions regarding your innovative work.

How much gas is produced daily and for which purpose do Tonle Sap Lake communities prefer to benefit from the produced gas (for cooking or electricity production)?

What is the average temperature of the water? Do you achieve mesophilic or psychrophilic conditions and how is the pathogen removal efficiency? What is the amount of digested sludge that you remove and how frequently you do it? As I understand, you use the digested sludge in floating gardens. What kind of plants have you selected for these gardens?

Thank you in advance.

Regards,

Gökce
M.Sc. Gökce Iyicil
Research Assistant
Technical University of Munich
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Re: Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE) 24 May 2013 07:38 #4485

  • robhughes
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Thanks Julius and Gökce,
Yes external damage is a key issue with the plastic-style digesters, so we have been trying different materials such as more durable fibre-reinforced plastic, as well as protection options (eg against UV damage). We're also currently using modified HDPE water tanks.

Julius I'm not sure rotation around the axis would help mix very much unless there were large seams etc? Also would need to consider gas offtake.

We're also looking at using the bioslurry in aquaculture ponds at our test site and land-based sites, however on the lake itself direct output to fairly open fishcages is more likely. This is already done with the manure, so essentially we're adding a stage to reduce pathogens and extract energy. We're also working on floating gardens and planned to have these also part of an integrated system producing pigs, fish, vegetables, and biogas - basic versions are operating, but still need improvement. Gökce we've tried to encourage climbing & small shrubs eg beans, tomatoes, gourds, eggplants etc - so there is separation between the slurry application and the produce itself.

The temperature in the lake water is typically around 26-33 degrees, so fairly stable. Due to this, thermal transmission in water, and the simple/low-cost nature of materials involved we're only going to be able to achieve mesophilic biodigestion. The first round of systems are achieving 2-log pathogen reduction, which we can hopefully improve with some modifications.

We're still collecting data on the gas production - but it seems to be around 300L biogas daily average for a 500L system (say with 2 pigs - around 6kg/day = 13L bioslurry). We've been very happy in most cases with the amount of biogas being produced and used by people with small systems and few animals. Our next round of experiments should give us a better idea of the potential with human waste and water hyacinth. Of course the gas production by human waste will be less than with pigs due to the quantities, and we're keen to discover if we can supplement the feed to make it feasible without animals.

Cheers,
Rob
Rob Hughes,
WASH Manager,
Live & Learn Environmental Education
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Re: Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE) 05 Jul 2013 04:45 #4939

  • gabrielleclare
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Hi

I'm Gabrielle McGill. I'm a volunteer with Engineers without Borders who is working at Live and Learn Environmental Education Cambodia on this project.

On Monday I, on behalf of Live and Learn, participated in an online discussion with 3 other BMGF grantees who are also working with biogas systems.

You can view the discussion on SuSanA's youtube channel here. The discussion of our project starts at around the 52 minute mark:
Gabrielle McGill
Engineers Without Borders Australia Volunteer
Live and Learn Environmental Education Cambodia
WASH Engineering Advisor
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Last Edit: 26 Jul 2013 12:20 by muench.

Re: Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE) 26 Jul 2013 12:15 #5145

  • muench
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Here comes my fourth and last transcription from the expert talk on 1 July (see here for an explanation about the expert talk in general: forum.susana.org/forum/categories/98-res...-dealing-with-biogas). Gabrielle’s topic was different from the other three because she is not working in the lab but doing applied research.

I welcome you to watch the online discussion that we recorded with Gabrielle McGill on 1 July where you can learn more about the research with floating biogas digesters on the Tonle Sap, carried out by the NGO Live and Learn Environmental Education in Phnom Penh in Cambodia. Gabrielle’s explanation about her project (with 3 powerpoint slides - see file below - and with that lovely Australian accent!) starts at 51:37 into the recording; it is followed by questions and answers that start at around 1:00:00 (sorry there are some small technical problems with the sounds towards the end).

I have added the Youtube link below to start at exactly the right time:

youtu.be/-0K24hkl1qk?t=52m12s

I found the following points from her presentation and from the questions very interesting:

(1)
Unlike the other three experts, her research is very applied, working directly in the community with real people and real waste. She said they now have 30 systems in the community. There are actually 1.6 million people around Tonle Sap Lake, most of them are “floating communities” with “floating houses” and lacking sanitation systems. She also mentioned that there are many pigs (are the pig stables floating, too? Or how does that work?).
They were experimenting with two types of digesters together with the local university; the digesters are also in the water and float. The one type is cheaper and from plastic sheets (read and white stripes on the photo, see pdf file below); the other is from plastic water tanks (same photo).

Clipboard03.jpg


In the experiments they were using pig waste, because pig waste is also a big problem with the communities – normally it just goes into the lake, I presume.
They are working with a 30 day detention time in the digesters and were experimenting with different combinations of pig waste to human waste and different retention times. They were focusing on gas production and pathogen removal as performance indicators (Gabrielle: can you share the research results with us?)
They ran training sessions with the villagers on how to fix things if something is broken with the digester. There is a flexible hose to connect the biogas from the biogas reservoir to the house where the biogas is used. The villagers can replace all their firewood needs with the biogas which is very impressive (must be due to the pig waste, as you get a lot of biogas out of the pig waste).

(2)
She mentioned a National Biodigester Program in Cambodia, which offers subsidies for different types of digesters. In the future, LLEE will partner with them. This National Biodigester Program has developed a simple sulfur removal system to clean the biogas of sulfur (Gabrielle: photos for this system?).

(3)
In terms of cost, she said their smaller systems cost 200 USD (made from a plastic water tank). This is still a lot for a Cambodian household, but it would pay back after 2 years when considering the value of the biogas produced compared to the costs of firewood.

(4)
I asked her if she had added algae to their digesters. She said they have not tried it with algae but with water hyacinth which is a noxious weed on the lake (what were the results?). She said there is probably some people who would be interested in having even more biogas, even though they already have a lot.

(5)
I also ask her about safety aspects with the biogas systems (possibility of explosion). She explained their risk management measures:
  • They use safety bottles (what is that?)
  • The systems operate at low pressure: the sludge should be pushed out through the outlet rather than allowing gas build-up in the tank.
  • The gas reservoirs are installed well away from the houses and from flames.

And she pointed out that the perception of risks is also different in Cambodia because it has to be seen in relation to other risks that the communities have to live with and manage.

(6)
Jianmin asked if there was any mixing in the digesters? Gabrielle explained that there is no particular mixing system inside because that would be too expensive and complex. Mixing takes place by the new waste that is added per day. Also the waves (in the case of floating digesters) will help with the mixing.

I hope that some of you find this useful. Please don’t hesitate to ask further follow-on questions to Gabrielle and Rob, as this is an ongoing applied research project which is continually producing more results and increasing their level of experience.

Regards,
Elisabeth
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Last Edit: 26 Jul 2013 12:31 by muench.

Re: Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE) 26 Jul 2013 13:53 #5146

  • JKMakowka
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Interesting updates.

With the "safety bottles" she meant most likely a pretty standard flame trap like illustrated here: www.adelaide.edu.au/biogas/safety/flametrap.jpg
(They are usually made out of bottles, hence the name)

Regarding the use of water hyacinth:
Do they have any easy way to shred it to small easily digested pieces? The lack of such is the main problem with using those as biogas feedstock here in Uganda. Even worse in that regards are all the plantain/matoke waste products which are created in rather large quantities on markets and in the households.
Krischan Makowka
Technical Adviser at the Uganda Water and Sanitation NGO Network (UWASNET)
www.uwasnet.org
Last Edit: 26 Jul 2013 20:50 by muench. Reason: typo corrected

Re: Energy recovery & waste treatment with floating biodigesters (Tonle Sap Lake, Cambodia - LLEE) 30 Jul 2013 10:28 #5171

  • gabrielleclare
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Hi,

Thanks for the transcript Elisabeth. I think your answers summate the questions well.

In answer to your questions. Pig pens do infact float, I've attached a photo for those interested in the floating pig pens.

We are just finalising some of the results from our initial experiments now and will hopefully have a document uploaded onto the library soon. But preliminary results have shown that the biodigesters are very robust systems and capable of working with feeds of pigwaste, pigwaste (75%) and water hyacinthe (25%), and pig waste(92%) and human waste(8%). All feeds deliver similar results in terms of pathogen reduction and gas production, though mixed feeds appear to produce slightly higher amounts of gas than the pig waste alone.

Some villagers have been able to replace all of their firewood with gas, this is due to the use of pigwaste in the biodigesters. Though work from NBP suggests that if you could collect similar amounts of human waste you would produce similar amounts of biogas it just happens that pigs produce more waste and hence more gas. More information for the National Biodigester Program (NBP) can be found here www.nbp.org.kh/

The safety bottle that Julius mentioned is the one we use in our systems.

Julius to aid digestion of the water hyacinthe at this stage we have been cutting it into pieces of approximately 2 cm using a machete, I don't have any experience with the plantain/matoke products you mentioned.

Kind Regards,
Gabrielle
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