Renewable Matter # 3 / April

Straw Yellow Gold

by Federico Pedrocchi

We have a feeling that the 21st century will be a great era for urine. Obviously, its central role in the existence of living beings does not need to be rediscovered, in other words, it does not mean that in the 21st century we must reappraise it and try to wee more often since it is unavoidable.

However, there are various sophisticated plans not to throw it away. This is happening within a cultural panorama that I find extremely fascinating: the most advanced technologies enable us to identify virtuous behaviours connected to our fundamental actions as living beings inhabiting this planet. Nevertheless, since these fundamentals also include the desire to be rich, it is not surprising that a crucial step towards the exploitation of the organic liquid was that of considering it as a substance that could be turned into gold. 

This happened around 1670, when chemistry was still such an approximate science that the colour yellow was seen as a good prerequisite to obtain the precious metal. In his cellar, Hennig Brand, a German alchemist, collected fifty buckets of urine and kept them for several months while adding several substances until he obtained a yellow mash, a sort of wax, that he could not sell to his contemporary jewellers but he discovered that it reacted with air and ignited. That mash was called phosphorous. Its potential was immediately understood and soon we learnt how to get it with less unpleasant methods compared to buckets of urine. A good choice for that era and those that followed.

Today, however, we cannot ignore that our body produces phosphorous, thus its extraction from mines of phosphorite is a little bit silly. 

Phosphorous is an essential element in soil fertilization, together with potassium and nitrogen, all present in abundance in the yellow liquid. In the Netherlands, it all started with a bang in Amsterdam: a square full of purpose-made urinals for the collection of urine. Now, a fundamental female variation is being figured out. In reality, the aim is not to invade squares – although this technological format could be used for example on the occasion of big concerts (for political rallies as well? Better be careful) – but to devise upstream strategies to introduce in people’s houses. It can be done, thus avoiding dumping everything into the sewerage system. Just some numbers: from 1 million people, 1,000 tons of fertilizers can be obtained every year. This is an enormous amount! And this is without taking into consideration animals, those in farms for example. 

And electricity as well. A litre of urine can power a mobile phone for six hours. No, I am not proposing unsightly smartphones in the shape of ducks. We must broaden our horizons: there are various ways of producing electricity from urine. For example, it is perfect – and they love it – for feeding hordes of bacteria that, by breaking the chemical link of organic matter (because they eat it), produce an electron flow. In this case, the technology is based on so-called Microbial Fuel Cells (MFC), it basically entails feeding bacteria in a device equipped with an anode and a cathode. In other words, good, old electrolysis.

According to some estimates, daily availability of urine from humans and farmed animals amounts to 38 billion litres. If with one litre you can phone for 6 hours, such amount means 228 billion hours a day. Will this be enough to satisfy our needs to be connected everywhere or will we have to resort to diuretics?