According to World Bank (as shown in Wikipedia), 37% of the population lives off $1.25/day. At that rate, the toilet drain pipe could be diverted into a 5-gallon bucket with volume graduations carved into the inside of the bucket.

a local citizen could be hired at $5 per 8-hour shift to empty bucket and record volume after each usage. You could have 24-hour coverage for 2 weeks. You would be under your $200 budget, you would get very accurate results and contribute to the local economy.

 

According to World Bank (as shown in Wikipedia), 37% of the population lives off $1.25/day. At that rate, the toilet drain pipe could be diverted into a 5-gallon bucket with volume graduations carved into the inside of the bucket.

a local citizen could be hired at $5 per 8-hour shift to empty bucket and record volume after each usage. You could have 24-hour coverage for 2 weeks. You would be under your $200 budget, you would get very accurate results and contribute to the local economy.

And whose going to pay all of these bucket-emptiers and where will the money come from? From all of the other people that are living off $1.25/day?

 

And whose going to pay all of these bucket-emptiers and where will the money come from? From all of the other people that are living off $1.25/day?

I believe the NGO has the $200 budget.

 

I believe the NGO has the $200 budget.

This is the man for the job.

 

Thanks Poopscoop, the OP did say they had a $200 budget. I was a bit surprised they were willing to spend that much on developing, building and installing an electronic instrument to automate something that could be done by a person.

The root cause of the problem is that the septic tank is filling up too fast. The money might be better spent confirming the septic tank was built to reasonable specifications based on the size of the community using the toilet - even if it is used as a private wash basin at the same time. Engineering/plumbing standards are widely available in local building codes throughout US communities. I am sure people in other parts of the world don't "process" food much differently than we do.

Finally, the $200 could also be spent by hiring citizens to dig a bigger pit and allow longer residence time for the sh$t to stew before flowing into the drainage field.

 

Guys, you are talking like this $200 is to deal with ONE latrine. The original post seems to make it pretty clear that this NGO is trying to instrument a CLASS of latrines -- their "basic pit latrine". Notice that the OP talks specifically about how the angle of the pipe varies from installation to installation but that, for his project, he could use a single fixed angle. Also note that his budget is $50, but that he can spend up to $200 for a more capable system.

What isn't too clear is whether this budget is for a single prototype test latrine, which is what it seems to me to be, or the budget for every latrine that is upgraded, which seems unlikely to me. My guess is that they probably want to instrument a handful of latrines to gather data on usage patterns and use that data to design better latrines.

 

It would seem to me that some very useful data for each toilet would be how many people visit, and how long does each one stay.

That could be correlated with the data of which pits fill the fastest: do the winners get the most visitors, or is it the length of time they spend?

I would also have to ask if there is a standard flush water bucket, as obviously a larger flush bucket would fill the pit the fastest.

A person in & out sensor/ timer/logger would be about the simplest to make.

 

... the idea is to get a general idea of what's coming in to the toilet. The NGO do not know how many people visit the toilet - and how much waste/water/volume each 'visitor' contributes. Some pits are filling much quicker than others...and they can't figure out why...the probability is that in some areas a toilet cubicle is the only private place around so lots of people may be showering in there....

So - number of users plus volume contributed per user would be great (and is far more important than breaking down solids/water etc).

I really think that's the key strategy - get the easy data first and only go after the difficult study as warranted. I'll bet it will never be warranted. Once some simple data is collected regarding a count of users, time spent, time of day and so on, it will be so much more clear what is going on and what additional data - if any - is worth collecting.

 

It would seem to me that some very useful data for each toilet would be how many people visit, and how long does each one stay.

That could be correlated with the data of which pits fill the fastest: do the winners get the most visitors, or is it the length of time they spend?

I would also have to ask if there is a standard flush water bucket, as obviously a larger flush bucket would fill the pit the fastest.

A person in & out sensor/ timer/logger would be about the simplest to make.

This sounds very sensible. Go for the low-hanging fruit, first. If the resulting data is good enough to achieve the goals of the project, you're done. If not, you have a much better understanding of what further data would likely move you further along.