So, today has been a little bit topsy-turvy because the President (of Bangladesh) died yesterday (aged 85) and so there has been an impromtu public holiday...but so impromptu that some places are taking time off, and others aren't. Thankfully we managed to get the samples over to the icddr,b and had a good chat with Dr Zahid there.
He's got some initial results from the first and second tests (raw sludge and 5 day-matured sludge) and we're seeing a factor 10 reduction in E-Coli and C. Perfringens. I'll graph the results and get them up asap.
Suman also told me that while they were taking samples, the sludge was so hard it was breaking the (disposable, plastic) spoons they were using to collect material. What this says about the quality of disposable cutlery here, versus the dryness of the sludge I don't know, but I reckon that's a good result - we can dry sewage slop to a hard cake in 5 days, with a meaningful reduction in pathogens.
I've also been looking at the temperature differences in the three beds, compared to those measured from our weather station (on the top of a bamboo pole next to the site):
This will probably be too tiny to read on the blog, but the green line is the bed that was vented for 12hrs during the day, and closed at night, the red line is the bed that was vented 24/7, and the blue line was our control, the open bed.
The spikes occur in the mornings, between 7am and noon, and the flat-ish bits between them are around 2pm-3am. This means there is the greatest difference between outside and inside (the roofed beds) in the morning, indicating that they are gaining heat rapidly once the sun rises, and also, they are retaining heat overnight. The last three or four spikes are where we closed the green-line bed 24/7, so it was basically a greenhouse, and you can see it was retaining more heat at night, and performing marginally better that the open bed during the day.
I'm not sure why the vented bed also improved its performance over the last few days, and I will ask Practical Action if they did anything to the roof during this time.
He's got some initial results from the first and second tests (raw sludge and 5 day-matured sludge) and we're seeing a factor 10 reduction in E-Coli and C. Perfringens. I'll graph the results and get them up asap.
Suman also told me that while they were taking samples, the sludge was so hard it was breaking the (disposable, plastic) spoons they were using to collect material. What this says about the quality of disposable cutlery here, versus the dryness of the sludge I don't know, but I reckon that's a good result - we can dry sewage slop to a hard cake in 5 days, with a meaningful reduction in pathogens.
I've also been looking at the temperature differences in the three beds, compared to those measured from our weather station (on the top of a bamboo pole next to the site):
This will probably be too tiny to read on the blog, but the green line is the bed that was vented for 12hrs during the day, and closed at night, the red line is the bed that was vented 24/7, and the blue line was our control, the open bed.
The spikes occur in the mornings, between 7am and noon, and the flat-ish bits between them are around 2pm-3am. This means there is the greatest difference between outside and inside (the roofed beds) in the morning, indicating that they are gaining heat rapidly once the sun rises, and also, they are retaining heat overnight. The last three or four spikes are where we closed the green-line bed 24/7, so it was basically a greenhouse, and you can see it was retaining more heat at night, and performing marginally better that the open bed during the day.
I'm not sure why the vented bed also improved its performance over the last few days, and I will ask Practical Action if they did anything to the roof during this time.
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