These days we take our clean water and the luxury of being able to flush our toilets and sinks without so much as a second thought but turn the clock back a little over 100 years and it was a problem which city leaders and engineers had at the forefront of their minds.
Up to about 1860, the River Aire was relatively unpolluted and full of life. It had plentiful stocks of fish: minnows, roach, dace and eels but pollution in the form of untreated sewage, led to the decimation of the fishstocks in the river downstream of Bradford, to the point where the city required a radical solution.
The Sewage Egnineers’ Department was formed in 1905 to undertake a scheme of water purification, the like of which had never been seen before. Main sewers beneath the city had been constructed between 1850 and 1855 but they channelled all waste, household and business, directly into the river.
A sum of £30,000 was invested over five years to conduct a series of experiments to look at the treatment of sewage in tanks and thereafter through artificial filtration, instead of filtration through the land.
In 1908, eight miles of new sewers were built, along with a filtration plant in Thorpe Stapleton. Work on a new main sewer, six miles in length began in 1913 but ceased in 1916 because of the war, then recommenced in 1922. It was dug beneath some of the city’s busiest streets, albeit without much inconvenience, being tunnelled most of the way. At its deepest, beneath Pontefract Lane, it is 103ft below the surface.
The tunnel ranged from three feet wide at its narrowest to eight feet at its outlet at Knostrop. The council even made 1 shilling per ton selling concentrated sewage manure to farmers.