In 1856, the Metropolitan Board of Works was established in London and it appointed Joseph Bazalgette as its chief engineer. As a result, Bazalgette embarked on his greatest work: designing and overseeing the construction of the sewer network in London, which effectively removed the threat of cholera and greatly improved the health of London residents and the general environment of the city. With immense foresight, Bazalgette estimated the size of sewers required and then doubled it, meaning that his original system is still coping with the population of the capital today. Nevertheless, his sewers still just diverted waste away and raw sewage was collected in tanks, the contents of which were discharged directly into the Thames a little way downstream at high tide. It wasn’t until 1900 (nine years after Bazalgette’s death) that sewage treatment works were constructed to deal with the outflow.


Map of the London sewerage system developed by Joseph Bazalgette 1858-1870 (Rudolf Hering, 1882 [Public domain], via Wikimedia Commons)

I am in awe of this amazing feat of engineering, but I’m also aware that it is the physical embodiment of Victorian values: the earth was created to serve man and human beings had a god-given right to use natural resources no matter the consequences to nature (which was also there for the benefit of mankind). And so, human waste was neatly and efficiently removed from sight (and smell), improving the lot of those in the city, but actually delivering the source of the problem to another location. Even during Bazalgette’s time, there were, apparently, those who objected to the fact that a valuable resource was simply being pumped into the Thames rather than collected and used for growing crops.

I wonder, therefore, what a different world we might inhabit had Joseph Bazalgette taken a different approach. What if he had valued this resource rather than simply seeing the (admittedly huge) problem? I’m not sure what sort of solution he might have come up with, but that change in perception in the nineteenth century might have seen modern homes not flushing fertility ‘away’, but having their own sources of compost production. Or maybe ‘away’ would have been to digesters or power plants or fertiliser factories.

There is no such thing as away. When you throw something away, it must go somewhere. Annie Leonard

Oh, poo!

Over the past few days, a link to an article on the Guardian website has been doing the rounds on Facebook (at least in the circles I mix in, which are mainly related to sustainability). It’s entitled Why the modern bathroom is a wasteful, unhealthy design and explains why we might not want to keep our toothbrush next to our toilet and why it’s such an environmental issue to mix the water we wash our hands in with the waste we flush down the toilet.

Basically, the issue with water disposal is that grey water (from washing) can safely be used to irrigate the land, whilst black water (from the toilet) needs to be processed to make it safe. By mixing the two together, we end up with a lot more highly contaminated water that has to be processed in some way. According to the Guardian:

Over 10bn litres of sewage are produced every day in England and Wales. It takes approximately 6.34 GW hours of energy to treat this volume of sewage, almost 1% of the average daily electricity consumption of England and Wales.

I don’t know what the figures would be if we separated the two sorts of water, but I know they would be significantly lower. The real issue in my mind, however, is that we see everything that goes down the drain as a problem – all waste water is pollution in the current paradigm. What we need to do is realise that, in fact, all waste water is a resource… faeces and urine contain valuable nutrients, and water itself is an increasingly rare commodity globally.

And if we are thinking about fertility, The nitrogen fertiliser industry is big business, closely tied in with fossil fuels… according to the International Plant Nutrition Index:

All N fertilizer begins with a source of hydrogen gas and atmospheric N that are reacted to form ammonia. The most-used source of hydrogen is natural gas (methane). Other sources of hydrogen, such as coal, are used in some regions. After hydrogen and N are combined under conditions of high temperature and pressure to form ammonia, many other important N-containing fertilizers can then be made. Urea is the most common N fertilizer, but there are many excellent N fertilizers that can be made from ammonia. For example, some ammonia is oxidized to make nitrate fertilizer. This same conversion of ammonia to nitrate takes place in agricultural soils through the microbial process of nitrification.

Because the production of hydrogen gas required for the synthesis of ammonia largely comes from natural gas, the price of this primary feedstock is the major factor in the cost of ammonia production. Ammonia factories sometimes close or open in various parts of the world in response to fluctuating gas prices. Higher energy costs always translate into higher prices for all N fertilizers. (IPNI)

The classic image of a compost toilet

The classic image of a compost toilet

So, we flush great fertiliser away down the toilet (remember a key function of urine is to expel excess nitrogen from our bodies), pay for that to be treated to make it safe and then pay even more to extract nitrogen from the atmosphere to apply to the land to grow crops. Somehow, this just doesn’t seem sensible. Why not turn the waste into a useful resource and avoid a whole bunch of pollution?

I know that most people are squeamish about composting toilets and they are currently not readily available for use in ‘normal’ houses, but technology is changing. Soon, you won’t have to deal with the waste yourself if you want to avoid the standard flush toilet, and you wont have to have a compost loo in the garden either. Take a look at Toilet Revolution if you want to see a whole range of options suitable for real homes.


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