Horizon (1964)

Season 58: Episode 2

Dr George McGavin and Dr Zoe Laughlin set up base camp at one of the UK's biggest sewage works to investigate the revolutionary science finding vital renewable resources and undiscovered life in human waste. Teaming up with world-class scientists, they search for biological entities in sewage with potentially lifesaving medical properties, find out how pee can generate electricity, how gas from poo can fuel a car and how nutrients in waste can help solve the soil crisis. They follow each stage of the sewage treatment process, revealing what the stuff we flush can tell us about how we live today, and the mindboggling biotechnology being harnessed to clean it, making the wastewater safe enough to return to the environment.