TOPIC: Windmill-driven ATADS

Re: Windmill-driven ATADS 05 Oct 2012 01:32 #2397

  • christoph
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Hi Jim
Sorry I am confused . First I did not respond, as Sjoerd from my point of view mixes anaerobic treatment with ATADS and these are two different technologies. But now you are writing about methane as well. Maybe I´m of university since too long, but from my understanding Methane production is very sensible to aerobic conditions...simply does not happen in aerobic conditions. Could you indicate a paper that states Mathane production in an aerobic process?
Yours
Christoph
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Re: Windmill-driven ATADS 05 Oct 2012 10:01 #2401

  • sjoerdnienhuys
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I am mainly interested in the amount of methane or other GreenHouse Gasses (GHG) coming from the various sanitation systems, but I do not find much information on the subject. When Jim can do an off-gas analysis, it may turn out that the ATAD actually reduces the methane emissions as compared to other sanitation systems.

The methane production from faeces is a matter of deduction. All humans have methane producing bacteria in their intestines (anearobic). Cattle have mch more because of a different digestive system. When we defecate these faeces continue for a while to produce methane. This is observed by smell and in septic tanks. When the ATAD is fitted with (pour) flush toilets it is logical that some methane is produced. Maybe, by forced aeration the methane producing bacteria are rapidly killed off. This can be an additional environmental benefit of the ATAD ascompared to other systems. In that case it is worthwhile to measure and document it.

In general I think it is important that each santation system has a rating on GHG emissions, which are not limited to methane or CO2. Such rating can be a recommendation for specific systems versus other systems.
Sjoerd from The Netherlands.
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Re: Windmill-driven ATADS 05 Oct 2012 13:55 #2403

  • blackburn
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Sir, you raise a good point. We have always been aware that if the excreta has a low enough ORP methanogenisis would occur and we would have to do something. Even more locally to the users sitting on top of the reactors, if we cross 25% of the Lower explosion limit (mostly methane) a user could flip a cigarette in the reactor and the result would be deadly for a user. It has always been on our list and we will address it in our next run (since we are out of BMGF funds our progress will be proportional to the new funds we hope to raise). Thanks for you advice Jim
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Re: Windmill-driven ATADS 05 Oct 2012 18:43 #2405

  • blackburn
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Christof, Please don't quit being or "devil's Advocate. Most of your comments have bourn fruit! Our six months autothermal thermophilic AEROBIC digestion experiment to date shows mostly ORPs around -200 mv. This is an accepted proxy for estimating the electrochemicistry and particularly what might be the main terminal electron acceptor. For most of our run we were
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at -200 to -250 mv, dangerously close to the ORP related to methane formation. The system is really a mixture of all types of organisms and the orp shows some kind of average. We need to rerun with a home designed windmill and a sludge being much closer to strong aerobic ranges, >0 orp. and measure the methane at that level. I attach a chart showing the relationship between reactor temperature and ORP. Note we know we did not achieve the required temperatures, another reason for a second run.

I'm happy to discuss the issue. Jim
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Re: Windmill-driven ATADS 09 Oct 2012 17:08 #2429

  • blackburn
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Yes Christof, reuse of the water even to the potable point is technically possible, though too expensive for meeting Gates' target of less than $0.05/person-day. Right now the emphasis is on generating pathogen-free water. Regards, Jim
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Suggestion for Publication 03 Dec 2012 16:21 #2764

  • blackburn
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Hi.

We have 6 months operating data for our windmill-atad. I'm looking for suggestions as for where to publish. It is multi disciplinary 1) Environmental engineering, 2) chemical engineering, bioengineering, 3) sustainability, 4) energy production, 5)renewable energy production.

If you are not aware of the project, just search for ATAD

Thank you very much. Regards, Jim Blackburn
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Windmill-Driven ATAD (Autothermal, Thermophilic Aerobic Digester for increased pathogen removal) 03 Dec 2012 22:08 #2768

  • muench
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Dear Jim,

When you say a place for publication, do you mean a peer-reviewed journal? I could suggest the IWA journals: Water Research; Water, Science & Technology; Journal of Water, Sanitation and Hygiene for Development; or Water SA. What I like in particular about Water SA is that it has a good status (citation index) but it is nevertheless open access which I find important.

If you are not after a peer-reviewed journal, and just want to get it out, then the SuSanA library could also be an option.

By the way: I have moved your posting to become part of the thread that you started over a year ago so that it all belongs together. This new category will actually be populated in the next few months with information about all the ongoing research grants funded by the WSH team of the Bill & Melinda Gates Foundation (forum.susana.org/forum/categories/97-inn...ing-country-settings) - as part of the project to make the previously closed "Sanitation Network" run by the Foundation into a public-facing community here on this forum. You were I think the first BMGF grantee ever to make use of the SuSanA forum to discuss your research - so I call you an "early adopter".

Regards,
Elisabeth
Dr. Elisabeth von Muench
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Frankfurt, Germany
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Last Edit: 28 Jun 2013 08:59 by muench.
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Windmill-Driven ATAD (Autothermal, Thermophilic Aerobic Digester for increased pathogen removal) 27 Jul 2012 21:12 #2953

  • blackburn
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Hi.

We’ve just finished all the packing and will be picked up on Monday. Our team is looking at Wind-mill driven Autothermal Aerobic Digesters at a very small scale. We’ve run this system at scale for about 5 months, and we think it may work for people who live in places of moderate or higher wind. It’s thermal mass buffers changes in the environment. We’ll bring the system itself and show how it works as well as bringing a model that shows how the ATAD might fit into an enclosure. We are also very optimistic that water produced from the system will be so low in pathogens that it could, with a hand pump, allow the benefits of a flush toilet with treated water without the problems. The only problem (but a big one) was that we were unable to get the reactor above 34 degrees C when it requires 55-65 degrees C to do the disinfection. We believe that this is due to the inhibition and toxicity of the mostly-industrial waste sludge we had to work with.

We hope we can continue with an all biological WWTP return sludge which will simulate the final all excreta material and very high reductions in pathogens–the goal of the Foundation.

I am coming: to meet all of my colleagues, to learn from their experiences, to maybe gain some information of issues we’ll still have, after proving the disinfection potential, to introduce two of my co-workers and to have some fun.

Regards, Jim

++++++++
We have started a new thread, it was getting a bit long. The new thread starts here:
forum.susana.org/forum/categories/105-hi...l-report-and-results
Last Edit: 28 Jun 2013 08:58 by muench.
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