What's up with the sewage at Rio?

We’re all hearing about the problems with the water quality at the Rio Olympics, but what is actually causing these problems? Sure, they pipe untreated sewage into the sea, but actually cities all over the world have ‘marine outfalls’ which discharge sewage away out into the sea, and Rio’s is longer than many at 4,300m.

The issue is actually the rivers, canals and storm water drains. About a third of Rio hasn’t got a connection to the sewage system. It goes without saying that the people in these areas still create sewage, and it has to go somewhere. Every time it rains the storm drains, canals and rivers channel thousands of litres of raw sewage straight into the sea right at the beaches, notoriously at Guanabara Bay.

For some eye-opening statistics, Brazilian TV reported in 2015 that 8,200 litres of untreated sewage flowed into Guanabara Bay every second from the city’s rivers. No wonder it was found that if the Olympic athletes (or anyone else) ingested three teaspoons of this water it would result in a 99% chance of infection.

Managing sewage has always been in a challenge all over the world, not least in the UK. Victorian London battled the problem with the Great Stink from the river Thames. Today we have to manage 11,000,000,000 litres of sewage every day, at an enormous cost. Think about the costs associated with sewage from your toilets, through drainage on your property, to wastewater pumping stations, and finally to a sewage treatment works where it is separated, treated, and some of it disposed of to landfill. Sometimes there can be many pumping stations it goes through before reaching the sewage treatment works.

Rio’s worked hard to improve the situation, and although there is a way to go there are signs of improvement. The lesson we can learn is that there has to be a plan to manage sewage now and in the future, or it may manage itself in undesirable ways. For example, if you’re planning significant expansion to your site, what impact will it have on the sewage? If you want to start a manufacturing process with high water usage, do you have a system that will cope with it? Think about it.