Via a blog called The Engineer: Engineering in the time of cholera. Excerpt from a very interesting post by a civil engineer working for MSF:
Cholera is something we are not talking about often enough. The recent crisis in Haiti, though it received attention for a short period, has now slipped from the headlines. But that doesn’t mean to say things have got any better. In fact, they’ve got worse.
Since the outbreak began back in late 2010 over 4000 Haitians have died. Many thousands have been hospitalised. More than 200,000 have been treated. And the crisis is ongoing. This could be just the beginning of what is likely to become a very serious situation indeed.
Cholera is so deadly because it is a bacteria carried in the stomach, often without the individual carrier knowing they have it. In fact, is only when the level of bacteria becomes critical that a patient starts to show the symptoms of vomiting, diarrhoea and a high fever.
In Haiti, for example, for every single person who has been treated for cholera there are likely to be tens if not hundreds of times more who are carrying the disease without showing any symptoms. The likely actual figure works out at around ten carriers for every patient treated. That’s two million Haitians who are likely to be walking around with cholera at this very moment.
In turn, that equates to a million kilos of infected excrement being produced each day. And, due to the destruction caused by the earthquake, there are very few toilets or latrines, so the chances are that much of it is not being disposed of properly. Yes that is 1,000,000 kg of poop – or 1000 tonnes per day!
So why do I say this is an engineering crisis? Not only in Haiti, but around the world, tackling diseases like cholera only requires a set of the very basic engineering solutions.
If people do not have access to proper toilets and sewerage, local water supplies, including lakes and rivers, become infected by disease at an alarming rate. It’s a disaster relief engineer’s job to assess, design and build a suitable solution.
You can’t chlorinate an entire lake or the whole length of a river, so what do you do? And, how do you treat contaminated excrement before it gets into the water system?
This is pure engineering on a massive scale. It involves logistics and planning and basic techniques. It’s about using lime and acid, alkali, flocculants and chlorinating water to make it safe. But it’s also about much broader engineering skills: the ability to find solutions to problems and applying them practically.
There’s so much work to do. In Haiti, the fight against cholera is not over. It has barely begun. When the rains come around again, by November, we’re expecting to see a situation which is far, far worse.
