How to measure temperature, humidity and pH for UDDTs in a village in Sumba, Indonesia


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How to measure temperature, humidity and pH for UDDTs in a village in Sumba, Indonesia

Dear SuSanA friends,

In 10 days I'll be returning to a village in Sumba, Indonesia where we are in the middle of implementing a Rotary-YHS joint WaSH project with rainwater tanks, UDDTs, CLTS and hygiene-handwash training. I need to make some choices on fecal pile measurement techniques, and have 3 optons (below). Please provide candid and prompt feedback.

The UDDTs are in homes and school toilet blocks, using 3-hole fibreglass pans being made locally, stone-concrete single vaults (ganged together for schools), poured slabs for standing and under the vault, urine collected using tubes to jerrycans, anal cleansing brownwater into french drains. The feces will be stored in woven bamboo baskets lined with rice bag material, and when full pushed aside for further drying. The oldest feces baskets will be brought to a central solar drying bin for stirring and temperature rise, until finished humus is realized. In a few months, when we have a good flow of fecal material, we plan to have a trainer from DNAEverywhere bring portable lab gear, train YHS staff, and be able to extract DNA, send it off for use in the PhyloChip, to know absence, presence and abundance of the 800 gut bacteria in their database, plus archae of all types. By measuring samples carefully at every stage, we'll know the effect of the dehydration-heating process ... and eventually get it down to do this for X weeks/months, then that for Y weeks/months, and the result will be duplicatable - without any electronics or high technology. Link to 3-hole fibreglass pan being installed in toilet block: (most will be nicer colors).

The reason I write you is, a) we are working out solar dryers for the fecal piles, and b) as an interim step we want to measure temperature, moisture and pH in both home baskets and central dryer piles. In particular, 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.

Please understand this is a very primitive location. Villagers average education is 3rd grade, YHS staff (bless their dedicated hearts) are sometimes hard to train and akin to 15 year olds who know it all, but really don't. Children play and break things, for fun. Parents are not tight in their control. So I need to bring procedures that are nearly bulletproof, simple and repeatable - and get sufficient data to be useful.

The two solar dryers that seem most likely are:
(1) emptied 55gal drum that contained bitumin, painted black, rotated on an axis with air holes at each end, cut a small door for adding and removing material, stirring. Perhaps weld vanes inside (like cclothes dryer) to improve turning and breakup.
(2) a container constructed from corrugated zinc-coated steel, tied together with timbers or bamboo, painted black - it might be raised (slat floor and screen allows some airflow) or rest on the ground; 2 dividers create 3 chambers of about 1m cube. The feces basket material would be added to the bins in batches, the trained operator knows and puts signs on which is "fresh", older, and oldest.
Link to soiler dryer ideas:

I have considered three methods for measurement that might be suitable, for a year or so:

1. using separate probes (soil moisture, soil pH and temperature), writing results manually say mid-afternoon once each day, and bring the papers. Advantage, no new technology for recording, inexpensive (maybe $400USD for probes including spares). Disadvantage, the founder of YHS says they won't do it, certainly not consistently, and sampling multiple points allowing the gauge to settle may be past the limit of what we can train with confidence.

2. using Hobo data loggers - each micro station has 4 wires, with temp and soil moisture sensors. This allows each vault to measure temp/moisture in 2 baskets - we can do two homes as samples - and do the central fecal piles with 2 more loggers to provide probes for the 3 bin container, or 3 rotating drums. The staff would receive data from each microstation monthly using a shuttle, download via USB to laptop, and email to the management team. Advantage, reliable data taken equal times (e.g. hourly or every 4 hours), stored, comparable by dates to weather and notes by staff from the field. Disadvantages: cost (over $3K), wires and plastic cases could be a target for child destructiveness, need for a fence, training on using the shuttle and software, if damaged not replaceable locally. Sensors on wires need to be removed each time a basket is taken away (or contents turned) to avoid damage; and removed each time the drum is turned, or the pile in a bin is turned. Links to microstation and soilmoisture sensor

3. using iButton Thermocron or Hygrochron plus manual pH probes. Advantages: lower cost (maybe half), the iButtons in stainless steel cases survive rough handling, very small (need colored fobs to find them in the piles), use similar readings with a shuttle, download and email. Disadvantage: at $30-90 a pop, easily lost or stolen, not replaceable locally; and the software isn't as friendly. Hygrochron only measures relative humidity (e.g. in air) may not be as good, or any good, compared to soil moisture sensor by Hobo. And blue dot receptors for iButtons seem to be only connected to laptops - have to bring laptop in the field, rain, slippery limestone, risk of damage. Link to Hygrochron sensor and iButton system Only shuttle type device so far this bluetooth link to Android phone

Obviously, overall, we're trying to get some objective quantification of temperature, time and safety of the fecal humus output - monitor that for a year or more, along with the DNAEverywhere identification - but end with a process that needs no gadgets or high-tech, and the people can replicate it home by home, village after village.

So my questions for you are:

A. Which would you use, and why?

B. What suggestions do you have for overall or detail process improvements?

C. What tips do you have for training the staff - and incentivising homeowners to manage the children risk and cooperate fully?

D. What papers or articles ought we read, in a the couple days before traveling (send links)?

Apologize for the long message, but thought if I gave this to you all up front, fewer questions and delay.
Fire away ... and thanks in advance for your time and consideration.

Stew Martin
Rotary District 5100 Water & Sanitation Resource Chair
Rotary Club of Seaside, Oregon
Primary contact for TRF GG#1410619
stewmartin 2 at gmail (omit spaces)

(Possibly joining in this thread will be Dan, Bill or Allart, part of the solar dehydrating team on this project)
Stew Martin
Rotary Club of Seaside, D5100

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