The town as a concentrated source of reclaimable water and materials. Opportunities for an engineered conservation strategy.

A fierce theoretical debate is ongoing about the human species’ existence itself being sustainable for Earth and for living world. In the meanwhile cities, which are considered to concentrate the mankind’s ecological footprints, are steadily growing and gathering huge populations worldwide. This paper assumes that margins do exist to relieve the man’s burden on Nature to some extent, and that – regardless of our general concept of the matter – these margins should be exploited. The focus of this note is on beneficial use of waste water and waste to spare new resources and to create filter areas close to towns or belts around them. A brief reference is made to some official declarations and indices published on biodiversity in anthropic environments, such as the one from UNEP.