Industrial waste recycling

If human waste was not to be flushed into urban water courses, what could be done with it? At the beginning of the 20th century a so-called "Poudrette-Fabrik" was constructed in Kiel as an innovation in the field of waste management. Its purpose was to convert human waste into fertiliser to be sold to farmers. In 1900 the project started off with 3500 buckets of human waste collected in the city. Soon this system served nearly all households.
The factory was a success: the construction costs of the fertiliser factory were low, and the raw material was cheap and plenty. Soon, however, low-priced artificial fertilisers made natural fertiliser production unprofitable, and the poudret factory ceased operations in 1919. Human waste was flushed in water closets into the semi-enclosed Kieler Bucht. To solve the problem, a 30 km long collector sewer was constructed and wastewater was directed into the sea. A WWTP was not built until 1972 on the occasion of the Olympic games.