Robert Thom – Inventor of water filtration system
Robert Thom is one of the forgotten luminaries of the Scottish Enlightenment, but his work on water filtering was behind one of the major revolutions in 19th-century sanitation.
The cholera outbreak of 1849, one of three major epidemics of the disease to hit Britain in the mid-1800s, was a stark illustration of the dire consequences of polluted water supplies. It claimed the lives of more than 33,000 people in just three months.
The disease is thankfully a thing of the past in the UK, but if such devastation has now been consigned to history in this country and many other parts of the world, it is thanks in no small part to one Ayrshire engineer who developed an ingenious way of cleansing water.
So effective was Robert Thom’s technique that it is still in use today across the globe, from village communities in Afghanistan to the city of London.
Insatiable thirst for knowledge
Robert Thom began his working life in the cotton spinning mills, but the industrious young man from Tarbolton had an insatiable thirst for knowledge, and educated himself by attending evening classes at Anderson’s Institution, now the University of Strathclyde.
He went on to forge an extremely successful career in the textile industry, during which he attracted attention for his skill in hydraulic engineering, eventually designing a water system to supply Greenock that is still in operation today.
Thom's greatest achievement?
Arguably his greatest achievement, however, was the development of the slow sand filter – a simple, cheap, electricity and chemical-free device that can remove up to 99 per cent of bacteria from water. The filter works by making use of a naturally occurring barrier of fungi, bacteria and protozoa to collect any impurities in the water.
In 1804 Thom’s version of the filter was used to create the first ever city-wide water filtration plant, providing a flow of clean water to the whole of Paisley. The plant was such a success that other cities soon followed suit and, after dirty water supplies were finally identified as the principal means by which diseases such as cholera and typhoid spread, municipal water filtration was finally made obligatory across Britain in 1852.
Today, over 200 years since Thom’s innovation, slow sand filters are still used as an effective method of providing clean water. A significant proportion of the London metropolis is served by a filter largely based on Thom’s principles.
More importantly, perhaps, the relative simplicity of its design, its minimal environmental impact and low cost of installation also make the device ideal for poorer communities. However, it is arguably in the developing world – where water-borne diseases still account for four-fifths of disease – that the ingenuity of a former cotton spinner from Ayrshire could yet have its greatest impact.