Ian Mulvany

February 8, 2023

A note on technological disruption, unintended consequences, and poo

I enjoy listening to in our time (
https://www.bbc.co.uk/programmes/b006qykl), a radio show touching on all things cultural and scientific. I’ve listened to many episodes, but rarely retain any information. I’m going to blog short notes on what I learn from the episodes.

This post is about the great stink of 1858 when pollution of the river Thames led to such a public outcry that parliament laid out measures to reform London’s sewage system: https://www.bbc.co.uk/programmes/m001gjcm

The first thing I learnt was about the role that innovation played in the breaking down of the existing waste disposal system. Up until the 1830s people would bury their poo in a chamber in the ground floor of their houses. This was mostly solid waste. When the chamber was full night soil men would empty it and cart it out of the city to sell to farmers. 

These changes led to the breakdown of this system. 

First as the city grew it became less viable to truck waste further distances. 

Second, the adoption of the water closet (flushing toilet) changes things dramatically. This invention was made available to the public at the great exhibition of 1851 at the cost of one penny per go (this is where the term “spend a penny” came from). It changed the compassion of waste going into the cesspit. The waste would now be twenty times as voluminous, mainly liquid (from the water used to flush). This made it less economically viable to the night soil men, and the effluvia would also leak out into the water table. This is the key invention that overwhelms the existing system! 

Population growth - going from 1M in the early part of the century to over 2.5m in the middle part of the century. 

Lastly, competition from South American bird guano. This guano was cheaper for farmers to buy as fertiliser (even though it was being shipped from half way across the world!.  William Gibbs https://en.wikipedia.org/wiki/William_Gibbs_(businessman) led this industry, and there was even a ditty that said: 

William Gibbs made his dibs, Selling the turds of foreign birds

So the takeaway is that in this instance technical and economic innovation led directly to the unintended consequence of fouling the Thames, exacerbating cholera in the city, and creating a huge pollution problem. 

The next thing that I learnt is that in 1870 a boat downriver in the Thames capsized just as the new sewage systems were dumping into that part of the thames. Over 600 people died. This led to the adoption of a new technique for getting rid of the waste - putting it on ships, and dumping it into the North Sea. Thames Water adopted this practice in 1870, and continued getting rid of London’s poo in this way until 1998. In 1998 an EU directive banned this practice, and they had to start incinerating the waste into ash, which was then used to build breeze blocks. 

If you want to dig into in our time episodes more there is a fantastic site that allows you to explore the archive in all sorts of ways:  https://genmon.github.io/braggoscope/

About Ian Mulvany

Hi, I'm Ian - I work on academic publishing systems. You can find out more about me at mulvany.net. I'm always interested in engaging with folk on these topics, if you have made your way here don't hesitate to reach out if there is anything you want to share, discuss, or ask for help with!