IWA Development Congress - Nairobi

So, just a really quick update, we've received an award for our work!

I'm at the congress in Nairobi this week, at the KICC - a conference centre designed by a very strong-minded architect in the 70's...!

the globe rotates slowly the whole time...!

The main conference hall

you can even turn the volume up to 11...

View from the top of the tower

I'll feed back some more thoughts on the congress later...

Datasets from Phase 3

A quick retrospective on some of our results:

Ambient daytime temperatures were around 35oC, and the highest air temperature achieved in the drying beds was 60oC.

The sludge had a slower response time to outside temperatures, and retained its heat better at night (due to the specific heat capacity of high water content material versus air), and an interesting ‘step-up’ effect was noticed as the sludge dried out.

This meant that the average sludge temperatures during the 10 day test were actually comparable to the average air temperatures inside the drying beds, although the peaks were around 5-10 degrees different.  This suggests that air temperature is a useful proxy for sludge temperature in this context, although any maximal temperatures in the sludge are likely to be cooler than the corresponding air temperature.
(remember the temperature achieved by the sludge is important because if it can be held at 55oC for four hours, a meaningful (destructive) impact should be had on pathogens within the sludge.)

As it was, while air temperature in the beds did get over 55oC for 4 hours during the final days of the test, the sludge only reached this for around an hour.

Given the interesting step-up effect as the sludge dries, it would be useful to repeat the test for a longer duration to assess whether these temperatures can be achieved in the sludge during days 10-15 (for example).

There were minimal differences between the temperature gain of the polycarbonate roof and the polythene roof.  This suggests that the roof design is robust to changes in shape and size, and to a certain extent material - so long as the transparency is maintained.

Pathogens:
A 90% reduction was achieved across all three beds tested during this phase of work for the three core indicators (faecal coliforms, e.coli, and faecal streptococci).

Slightly better reductions were found in the unraked bed (a 99% reduction in faecal coliforms and e.coli) suggesting that the level of disruption of the sludge could affect the kill-rate.  However, the raked beds dried out marginally faster, and a little more completely.

This suggests a trade off between the speed of drying and thoroughness of pathogen reduction.  Given the increased manpower required for regular raking, if time is not critical, then an unraked approach would seem viable for FSM in this context.

Initial Datasets form Phase 3

Sunday 15th September

I've now started compiling the datasets.  First up, temperature readings:

This is the first time we've been able to monitor the sludge temperature, and it's interesting to see how it compares to the air temperature.

Other things to note, are the relatively in significant difference between the two roof designs, and the minimal impact (in terms of heat gain) of the raking strategies.  The unraked beds were lower maintenance (no need to rake each day) but observation suggests the raked beds dried quicker.  So I guess it depends whether you want speed (increased throughput) or faff.

Hopefully I'll be able to post some pathogen results in the next day or two, and some more indepth analysis of these initial results.

Phase 3 - Last day

Monday 9th September

This morning I hustled the samples over to the icddr.b and Dhaka University before frantically trying to get everything closed out on some other projects I'm working on before I go offline for a bit as I travel home via Dubai.

Another classic roundabout

Backstreet scene in Dhaka

Pineapple Market

Rushed photo of a nice pavilion we passed - apologies for finger - first time in years I've managed that!

Prof Hamida is helping us with helminth studies at the University of Dhaka

Totally did a double-take when I first saw this....!

 Finally, one thing that still baffles me, in so many places I have stayed they have installed a phone by the loo.

Call of Nature

Anyhow, hope to get some results up here soon, and some of the issues that are still outstanding.  In the meantime, it's back to the UK...

Last site visit for Phase 3

Sunday 8th September

Due to uncertainties over the ferry crossing - the car ferries are grounding on the silted up river with increasing frequency, and are often stopped/ half capacity with big delays - we tried a new tack in our mission to get to site:  the launch.  We got one driver to take us to the port, and then got on a passenger boat across the river, and met another driver on the other side.  It turns out this is actually quite a time efficient way of doing it, and we managed to time our arrival so we were the last passengers onto a departing launch, so no waiting around.

At site we got busy taking samples from the beds and the ground near the site - so we could compare the treated sludge with 'naturally present' background levels of pathgens and indicator bacteria.

Taking soil samples

Suman taking samples

Illustrating how dry we are getting it

Samples lined up ready for packing off to Dhaka

Suman practicing downloading data from the trust sensors (left)

The sludge was looking good and dry:

Although there was significant condensation build up inside all the roofs:

Images of the condensation issues

This will be an issue we need to deal with/ think about going forwards.
I also couldn't help notice how well the veggie plot was coming along...

On the way home we stopped off at a 'sweet shop' to pick up some yogurt and treats for Suman's family.

Again we took the launch back and were home in Dhaka before 6pm, 12hrs after we left this morning, which was pretty good going!

Roofs had been removed and put in an area considered 'less risky; while the buildings are flooded.  Unfortunately I think it got the roofs too - hopefully they won't rust too badly!

River scene

Our launch driver

Back in the office, crunching data

Thursday 5th September

Today I was combing through emails and other admin in the WA office in Dhaka, writing up blog posts, and checking out our half-way data.

(apologies for the blip in the external weather data - the receiver was accidentally taken off site for a few days)

What is interesting to note is that the beds remain a degree or so warmer than outside at the coldest points, but are significantly (at points as much as 20 degrees) hotter during maximal external temperatures.

It will be really interesting to see what happens now during the cooking phase.

Will get back to you on Sunday night with some feedback about that.

Mid-test Check on Phase 3

Wednesday 4th September

Before we left Khulna, I managed to get a photo of perhaps my new favourite roundabout...

Shrimp Farming is a major activity in this area.

Boy towing a barrel - there is something poignant about this.  

 On the way up to Faridpur evidence of the jute harvest was everywhere.  The jute stalks are held underwtaer for 5-6 days to rot, and then the fibrous inner is removed and draped over bamboo sticks to dry, and the remaining stalks bunched up in conical 'hats'.  The fibres are sold to jute factories to weave into jute fabric, and the stalks are used to make partition walls in huts among other things.  Roadsides are apparently great places to dry the jute out, so the road was pretty much lined with this kind of scene all the way to Faridpur (2-3hrs away).

Jute drying

Jute going to market.

 Anyway, finally we arrived back on site, and look! Its drying!
(this is 6 days after delivery of very liquid slop, and it has been raining heavily at least once every day)

Bed A - Raked

Bed B - Not Raked

Bed C - Raked

 A close up of the sludge in each bed:

Bed A - Crusty clumps, a bit 'pastey' at the bottom

Bed B - Very dry crust on top (~1cm) and pastey underneath

Bed C - As with A, crusty lumps and a bit pastey underneath

 There was a little condensation on the inside of the roofs, but it was quite minimal.

View of interior - you can see the temperature sensor we are using - about the size of a watch battery, mounted on a plastic keyfob.

Interestingly, as soon as we zipped it up (we were a day overdue on the 'cooking' phase) condensation immediately appeared, and the temperature shot up - sneaking your hand in, you could tell it was getting really hot in there.

We stopped for a little photoshoot before departing:

Myself and Suman (WA) with the Practical Action Team

Suman (WA), Mamun (PA) and myself

The seedlings are already making a great effort in the mini-garden.  The empty quadrant really is empty - no seeds were planted there, and the two green patches are different plants so the visual density is mis-leading.

The team had some interesting questions about using these plants once they are grown... "can we eat the leaves? will the pathogens from the sludge get into them?"  This indicates there is still some education to be done around use of compost.

I reassured them that if sludge is mixed with the soil, there is no way the pathogens could get into the leaves, but they may get onto them, through dirt/ leaves touching the soil, however given that the sludge has been both solar dried and composted, and will then have been exposed to the sun directly for a month or three on the top of the soil, then it is highly unlikely that any will still be viable.

We left the site all zipped up and cooking in the midday sun.

 Oh and I couldn't help but notice the fame-board developing in the Practical Action office - there are copies of all the newspaper articles about the project, and a myriad of photos of myself and colleagues from WaterAid on the walls...

Must remember to think about what I look like more...!