[Start of Page 2 of the discussion]


Well the simplest and most accurate way to do this would be with thermocouples and a datalogger. You may have to consider the size of the data file to email. Maybe the data could be put onto a usb stick and sent in some other way instead?

I am a bit surprised that this would cost $3k, I would think it ought to be possible to do it for much less.

Regarding this:

I hope we can achieve 55-60C or more to inactivate Ascaris and kill all bugs (technical term), and see how high the pH gets and the change in moisture from start to finish. It's a rough measure, but better than most I've read about.

I think research indicates that it is very hard to achieve conditions will consistently kill off ascaris. And 55-60 degrees is not going to "kill all bugs" - partly due to diurnal temperature variations (so it doesn't necessarily stay at that temperature for very long) and partly because there will be different patterns of survival at different positions within the windrow/heap. I suspect the simplest method in the long term will be to identify positions where the conditions are worst (probably the edges and bottom of your windrow) and to monitor those. If they can be shown to have got to minimum standards, it will be fair to assume the rest have.


But I like your research model, it will be fascinating to see what you find out.

I spoke to someone a while ago who ran a company looking at dna analysis that you mention here. I think that is very useful idea, given that the amounts of material needed would be much lower than if you needed to do a full microbiological assessment.

I do not know enough about microbial genetics, but I assume that you have determined whether dead pathogen dna is retained in the material? Otherwise this may not be a particularly useful measure of pathogen destruction.

Edit: sorry, I missed that you mentioned this point. If they can determine dead DNA from live, this sounds great.

There is not that much influence of pH change (from what I remember).

Sorry I was in a hurry and did not express myself right.

For sure in general a pH change has a very significant influence on pathogens. What I wanted to express is that there is not much influence on the pH by the drying process - therefore - unless you do not actively change the pH you will have no effect on the pH.

Concerning publications I was trying to find the publications of University KwaZulu-Natal - about UDDT -effect of temperature moistures and (pH? - can´t remember) Elisabeth can you help? But again my point is the pH change in the UDDT.

Regards
Christoph

JKMakowka wrote: About those solar driers, are you sure those designs will heat up sufficiently? Seems more like ambient heat air drying without some parabolic concentrators or a greenhouse. Did you have a look at those solar sterilisation devices Sanivation is using in Kenya?

First ambient is 35-40C, so another 15-20 C is all that's needed <smile>.

Had seen, just looked again at Sanivation. Those are small drums! For the drum and reflector approach, we had in mind (in diagram #1) 55 gal drums used in bitumin, but we were thinking to place a bunch of holes in the ends for airflow. I gather what Sanivation is doing is first dry and crumble; then inactivate in 5+ hours of concentrated heat. We can probably use a more closed rum with galvanized sheetmetal laying under it, with a thin mylar reflective film in a curved shape (it won't be a parabola) to concentrate.
I believe we can point some concentrating reflectors at the metal box bins, also; painted black, they will absorb. Not as efficient as a cylinder drum over a parabolic sheet, but maybe good enough.

JKMakowka wrote: I think a sludge drying bed in a greenhouse maybe with an added off the shelve solar water heater connected to pipecoils at the bottom of the bed might work well too.

I think that's too complicated, and there's not much land. Water is at a premium.

JKMakowka wrote: In any case you could use heat indicator paint/tape in small pouches added to the material, see: www.fda.gov/ICECI/Inspections/InspectionGuides/ucm072529.htm
(Sorry I am on a phone and couldn't find a better link quickly).

Hadn't thought about that. Good idea. However, 2 drawbacks - a) the dots or markers measures the temperature of the outside of the bin (or maybe inside of lid) - not the center of the pile, which would have a lower temp; and b) it is either reversible (someone has to be there and write it down) or nonreversible (they write it down by end of day). In either case, that's what our NGO partner feels will not be done. That's why I like the data logger approach - it will capture temp data in the middle of the pile, every hour (as example) - and store 2 or 3 months of data - then download it all.

From this thread I do now have the idea to package up some fecal pile material and send it to a lab that could test for multiple bacteria, ascaris etc. WIll have to see if we can find one in Bali. Surabya and Jakarta are far away, and I imagine the time delay would skew the results.

Thanks for this input, JKM !

Hi JKM,

Thanks much for those comments. I'm not enough of a nerd, and we don't have time before traveling, to do a RaspPI, beaglebord or arduino. And I would have more confidence about durability and success with a commercial setup. But this is good to know about.

Understand about petrilm ... dilution, sensitivity. So I won't bother with that.

Read about DNAEverywhere www.thermopileproject.com/dna-everywhere/ - so far working with Sasha at SOIL they are doing composting; but they want to be "toilet agnostic, hence work with our UDDT project. My understanding, after asking about DNA fragments, is that by doing repeated samples they can tell (over time) that the bacteria associated with human guts have reduced, or become eliminated ... i.e. distinguish the alive from recently dead. But this has to do with communities of organisms and probability. Frankly beyond me.

Forgot to add: About those solar driers, are you sure those designs will heat up sufficiently? Seems more like ambient heat air drying without some parabolic concentrators or a greenhouse.
Did you have a look at those solar sterilisation devices Sanivation is using in Kenya?

I think a sludge drying bed in a greenhouse maybe with an added off the shelve solar water heater connected to pipecoils at the bottom of the bed might work well too.

In any case you could use heat indicator paint/tape in small pouches added to the material, see: www.fda.gov/ICECI/Inspections/InspectionGuides/ucm072529.htm
(Sorry I am on a phone and couldn't find a better link quickly).

Hope that helps!

Yes online measurement (Edit: that means continuous automatic measurement, often but not necessarily transferred over a network) should be doable, but I think you would be one of the first to give it a serious try, e.g. I don't think you will get a qualified recommendation here but rather plenty of "please tell us if the equipment works well" comments

In theory (and if you are willing to do some fun hardware hacking) you should also be able to get something working with cheaper equipment based on an arduino or something like a beagleboard (beagleboard.org/project/sensorcape/ ) or RasberryPI. But pH sensors are more expensive and the "professional" equipment you are quoting is probably much more durable especially in a tropic climate.

About the 3M petrifilms, well unless you are confident that your heat-treatment will more or less pasteurize the faecal material these are way too sensitive and doing proper dilution series is next to impossible in a "field" setting. Furthermore the concept of survival of indicator bacteria like Ecoli is more or less based on equvivalent survival rates under environmental conditions and water-treatment systems and not really a settings like a compost pile.

Those DNA test sound interesting. Is their system actually certified / appropriate for testing treatment efficiency of faecal sludge? I would like to learn more, but I wonder how they differentiate between dead and living cells as the DNA usually is not fully degraded even if the sludge is already fully sterile.
Do they have a website or something like that explaining their exact process?

Hi Christoph,

Not sure what you mean "online". If you mean via wifi or Internet, not in Sumba: there is very poor and broken up cell service, and even land-wired ethernet is unable to do much.

If you mean data collection by devices, which data eventually ends up in databases or spreadsheets, then I agree. The challenge we face is how to get it collected regularly, well, and correlate it with events and other data.

pH not very useful? I'd like to know more about that. I had read the > pH 11 would make a significant difference. If not, would be one less thing to measure. Can you provide me with links to study showing it's of little value?

For moisture, even though it's not compost pile and moisture varies probably even more by location within the UDDT fecal pile, I thought to use a soil moisture meter. And the better one is the Hobo setup - but it has to be withdrawn to stir. The iButton Hygrochron measures RH (relative humidity), which is normally water % in air ... but I wonder if it would be a rough approximation of dryness in the pile. If so, then using 8 Hygrochrons would be $700 USD instead of 4x that for the Hobos.

Cheers,
Stew

Hi Stew,
Online measurement I think is very interesting and not out of reach - today it is relatively cheap (especially temperature) - which kind you use is up to you (and budget), actually in the vault the differences will no so important but on the solar drier - that will be a challenge.

I would just concentrate on moisture and temperature. There is not that much influence of pH change (from what I remember).

Later some more I hope....

Regards
Christoph

muench wrote: Thanks for the detailed description, very interesting. However, are you sure it is not a bit of an overkill what you are trying to measure there? Unless you are trying to commission several PhD students onto it.

A simpler and more doable version of UDDT product testing was carried out by Laura Kraft in 2010 in Kenya (she is now with Sanergy). Her report is available here:

www.susana.org/en/resources/library/details/1026

Hi Elisabeth,

Thanks for that citation. I've just now read the summary, and it does look excellent. But as for PhD students <LOL> they would definitely be required for her methods, along with a laboratory. On Sumba there is no laboratory, no microscopes, no one has ability to do cultures, sort out eggs, etc.

I brought 3M Petrifilm (e.coli+coliform) for water testing, which I gather can also be used for tests of fecal piles in water suspension, perhaps. (If you can point me to good protocol for this, please do.)

I am informed both by our NGO partner YHS and Rotarians that even staff of YHS, let alone villagers, cannot be trained to make notes of manual readings of handheld meters for pH, moisture and long-stem temperature. It's over their heads, and they will listen, nod heads, then not do it. Hence my reason for sensors with automated electronic logs - once set up, they can be left to gather data and the data is retrieved every month or two, and set back to us in US/England/Australia for analysis.

Our purpose is to track temperature and soil moisture now ... then in March, say, when we get the DNA extraction can be done and sent to Phylochip testing, we'll be able to correlate the temp/moisture over time with the bacteria/archae results. The hope is we'll see the actual results in detail, refine the process (e.g. more stirring, more reflectors to raised temperature for last 5 days, better rain protection) - and make a protocol that under-educated villagers can follow regularly.

Temp-moisture now, DNA later; correlate then after the study and refinements, go back to a simple procedure villagers can sustain indefinitely.
I hope that's more clear.

Now with that in mind, other comments or improvements?
Thanks for taking the time,
Stew

Hi Stew,

Thanks for the detailed description, very interesting. However, are you sure it is not a bit of an overkill what you are trying to measure there? Unless you are trying to commission several PhD students onto it.

A simpler and more doable version of UDDT product testing was carried out by Laura Kraft in 2010 in Kenya (she is now with Sanergy). Her report is available here:

www.susana.org/en/resources/library/details/1026

Kraft, L. (2010). Final sampling report for products from double-chamber UDDTs (faeces and urine). Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH

It is all very well described in there how she measured what. Very doable without having to spend a huge amount of money.

But I guess it depends on what you want the data for. If there are PhD students from the US involved, then it's a different story.

Kind regards,
Elisabeth

Thank you, Denniski for your kind words.
I agree, writing it up would be beneficial ... I'm so busy researching, doing, and keeping folks in 4 timezones in synch, barely have time to inform my own club, and the 16+ supporting Rotary clubs. But we'll see.

I look forward to any thoughts you, or others here, may have. I'm still a learning amateur, compared to many of you pros.

Stew

Stew it is a joy to see such a well-constructed and considered project plan!

Will review info and see where i can offer any useful suggestions

A write up on your overall approach as a case study would also be very useful for susana members i think, when there is time (how the project came to be, why there, why the system choices, community participation levels, challenges, project twists & turns etc)