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

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.