Why are there so many sewage leaks?
While sewage leaks are far from unique to London, London does make for a good case study in them. It’s a city which has seen drastic population growth, especially since the latter half of the 20th century and that has posed a challenge for its (rather antiquated) sewage system.
For a while it seemed that London had tackled this challenge and emerged victorious with the Thames being turned from the source of the “Great Stink” of 1858 to a river clean enough to be a haven for wildlife including the salmon which had previously deserted it. Unfortunately, the problem of sewage has reared its head again and while it is nowhere near as big of an issue as it was in 1858, it does raise the question of why there are so many sewage leaks. Here are four common reasons for sewage to leak.
Issues with piping
There are three common issues with piping which can lead to sewage leaks.Faulty seals – the seals on pipes typically deteriorate over time and if they deteriorate too far, then the pipes will develop gaps through which the sewage can leak. This typically happens at a domestic level.Burst pipes – if a pipe bursts then sewage will be able to get through the gaps and depending on the nature of the burst it may be a trickle or an explosive flood. At a domestic level, the way to avoid this is to make sure you take good care of your pipes, especially in winter.Punctured pipes – this is essentially a variation on burst pipes, but is slightly different in that punctures are caused by external forces such as tree roots, which requires a bit of lateral thinking when it comes to dealing with them. At a domestic level be aware of where your pipes are and what is above them. You may want to consider relocating young trees before they become too established and be realistic about the need to remove older ones, even if you are attached to them.
Flooding
London has become rather notorious for sewage leaking into the Thames after heavy rain overburdens the sewage system. This is not, technically, the same as an actual flood, but basically has the same effect. A flood can overburden pipes to the point where sewage is forced out in undesirable locations. London is currently building a “super-sewer” in an attempt to address this
Clogged sewer lines
People flush all kind of items down toilets and pour all kinds of substances down sinks. The end result of this is that sewer lines become clogged and cease to function correctly. London has become infamous for its fatbergs, but, again, the problem is far from unique to that city. The city of Charleston in South Carolina recently had to clear up a massive stack of “flushable” wipes, which weren’t. Unsurprisingly, water companies are trying to do their best to educate customers to stop this practice as it causes all kinds of problems and the manual intervention required to fix it is very expensive.
Failure at a pumping station
Sometimes there are failures at pumping stations which result in sewage leaking into waterways before it is appropriately treated. Out of everything which has been mentioned so far, this is probably the least common occurrence and when it does happen, it should trigger alarms (literally) making it possible to fix the underlying problem very quickly, but it certainly does happen from time to time, in fact, Thames Water were recently fined a massive £2M for an incident in 2015 in which failures by Thames Water allowed a significant leak of raw sewage into the Thames.
