Metropolis. Pt. 3, A big stink.

Documentary tracing the history of London's sewage disposal, including the early cistern device of Sir John Harrington in 1594, resurrected in 1775 by Alexander Cummings who created the water closet. The excess water created by these toilets flooded London's underground cesspits, with the build up of putrid, inflammable gases leading to a massive explosion in 1846, and a tidal wave of sewage that swept over workhouses above the Fleet River. Cholera was spread through London's water but it wasn't until 1858, 'the year of the big stink', that plans for an efficient sewer system were called for. Engineer Joseph Bazalgette created the London sewers but initially this just meant the sewage was pumped into the Thames further downstream at Barking. In 1878 a large number of people drowned in river sewage after the Princess Alice paddle steamer capsized. Soon afterwards, sewage treatment was initiated. Due to the city's increasing population, in the 1930s and 1940s the Thames was again in a foul state, with 80% raw sewage recorded in 1947. Sewage treatment works were built that made the Thames clean enough for salmon to return by 1974. The programme ends by noting the connection between the toilet and disposable products, and suggesting that the huge amount of water used to flush all this away means that a new, more environmentally sound waste disposal system is needed.