This book looks at Flush and Forget (FaF) systems, a traditional method of dealing with sewage which mixes everything (urine, faeces, pharmaceuticals, antibiotic-resistant material, personal care products, forever-chemicals, microplastics and a wider range of other pollutants) together and transports it by water. FaF cannot deal with these components and incineration is generally the only option.

There are better, less wasteful alternatives; vacuum  toilets, for instance, 'flush' using the force of vacuum rather than water and separate faeces and urine at source. There is far less waste water to be treated, creating opportunities for anaerobic digestion for green biogas followed by hyperthermophilic composting of the residue, and saving huge amounts of clean water.