What's that Smell Filter: Why can't most third world countries' septic systems handle toilet paper?

February 8, 2008 8:45 PM

I was recently in Guatemala and I know that there and in most of Central America and many other third world countries you can't flush toilet paper because their septic systems can't handle it. What's the difference between our (More Developed Countries) septic systems and theirs (Less Developed Countries) that ours can handle it? Is it a matter of water flow, sanitation processes, etc?
posted by bobdylanforever to travel & transportation (10 comments total)

I believe it's to do with the treatment plants. Most treatment plants in the developing world do not remove solids (Taiwan sewerage system is like this, but fortunately due for an upgrade)

this Wiki article explains all.

Scroll down to see section on developing countries
posted by mattoxic at 9:15 PM on February 8, 2008

When I was in Greece I was told it was because the pipes were too narrow.....not sure if that's true.
posted by purenitrous at 10:25 PM on February 8, 2008

(In Brazil) Part of it the issue seems to be at the consumer end (vs. the treatment center). I don't know the reason why but on the few times that I've accidentally dropped a little bit of TP in the toilet (or had some TP I would really rather flush), it usually doesn't go down. So then you stand there and wait and try flushing it again and eventually give up and hope everyone else doesn't know it was you. But I know that there are some places around that can handle it--not that you know in advance which places can or can't.
posted by wallaby at 4:54 AM on February 9, 2008

I believe it's to do with the treatment plants.

Not true. Most treatment plants in the developing world function only partially / periodically; from your link: In Latin America about 15% of collected wastewater passes through treatment plants and that 15% claim is pretty optimistic. Moreover, given all the weird stuff people flush, TP is not in the slightest the biggest problem for treatment plants -- you wouldn't believe the things that come in through the pipes.

As Wallaby suggests, it's at the consumer end, for what I think are three or four reasons. Water-flush toilets are surprisingly delicate creatures -- they need to be connected to drain pipes of specific sizes and laid at exact slopes (too flat and they clog; too steep and the liquids drain faster and the solids clog) and made from certain materials connected in specific ways; they need TP manufactured to specific tolerances (ever tried flushing a wad of paper towels?); and they need reliable and fairly pure water sources. In many houses in the developing world, several of those factors won't be there -- smaller outflow pipes, laid a bit too haphazardly and with too many bends; water supply that comes and goes; TP of uncertain origin; and so on.

But feces is water-soluble, so even a very imperfect system can tolerate poop being flushed down it; the less soluble TP (especially imperfect TP that might be too tough or too thick), feminine hygiene products, used condoms, and other goodies will cause clogs where poop won't. Hence the trashcan next to the toilet and the signs saying "don't flush the paper!"

Of course, at some point that prohibition becomes cultural rather than simply practical, and even in houses with perfectly-functioning modern toilets that can take anything you throw at them, you will still see the TP bins. I have even seen those TP bins in outhouses, where there is no flushing apparatus whatsoever.
posted by Forktine at 6:36 AM on February 9, 2008

When I've been in Mexico under the "no flushing paper rule," the toilet paper simply did not go into the pipes when we flushed. It'd just sit there in the toilet waiting for someone to clean it up. Nasty job.
posted by jmd82 at 7:42 AM on February 9, 2008

Every septic system that handles toilet paper needs to be pumped periodically, as the toilet paper doesn't break down completely. I wonder if a lack of available septic pumping services might affect the design of the plumbing...
posted by bricoleur at 8:38 AM on February 9, 2008

I live in Taiwan and have been told it's a matter of the diameter of the pipes used - I don't know if this is true. The idea of having a bin next to my toilet that's filled with excrement is too mush for me to handle so I flush it anyway and haven't had any problems...

I've also spent fair amount of time in Bolivia, Kenya, and India and haven't been told not to flush my toilet paper.
posted by Dr.James.Orin.Incandenza at 10:57 AM on February 9, 2008

My experience in Indonesia was that the diameter and angle of the pipe in many buildings wasn't supposed to take anything but water/liquids and "easily soluble" solids. Big gobs of paper were a no-no.

If you had a proper mandi you could just ladle water out of the tank and rinse off, which was very refreshing, and meant you didn't need paper at all.

In some more western-ish city buildings it didn't seem to matter much one way or the other.
posted by gimonca at 2:05 PM on February 9, 2008

Of course, at some point that prohibition becomes cultural rather than simply practical, and even in houses with perfectly-functioning modern toilets that can take anything you throw at them, you will still see the TP bins.

And, oddly, in just about any semi-public venue frequented by recent Central American immigrants. The Home Depot in Falls Church, VA, has trash cans next to the toilets (men's room!), I suppose because otherwise the poopy TP would end up on the floor. I've been to Guatemala and El Salvador, and have been on the other side of the equation--it was virtually impossible for me to remember to not drop my toilet paper in the toilet. Old habits die hard, I suppose.
posted by MrMoonPie at 7:59 PM on February 9, 2008

Late as always; still, allow me to chime in: Firstly, the "third world" term, that's like so passé, particularly with the Cold War over. And more than a bit offensive. Secondly, I've (almost) always lived in Guate, and I've always flushed the TP down the toilet... but of course with the caveat of using plenty of water because in some toilets you just don't know.

So like some have said, it's not to do with the pipe system, rather, with the small-ish toilets and their smaller pipes.
posted by papafrita at 7:50 PM on March 22, 2008