An Alternative Model For Water Supply and Disposal in Cities Part 2 Project 2011 Michael Chadwick University of Cambridge | UK Odum [1991] described cities as “only parasites in the biosphere.” Cities are opportunistic, highly dynamic, the focus for many natural and anthropogenic inflows and outflows but also resource restricted with increasingly dense populations. They remain dependant on their hinterland, which may be global, to both provide inputs and deal with waste outputs from the city, colonising ecosystem support areas at least 500-1000 times larger than the area of the cities themselves [Folke. et al., 1997].19th Century cities in the west developed a vast subterranean water supply and disposalinfrastructure focused on centralised treatment plants. Rapid urbanisation, compounded by a changing climate, will pressure existing city infrastructure. It is vital to create sustainable urban water supply and wastewater treatment systems within cities. The inadequacy and inefficiency of these existing systems demands radical reconsideration and innovation. Stable holistic natural systems provide at least some of the clues as to what these might be.By reconsidering the requirements of the built environment as part of a much larger,interlinked system, the treatment of wastewater could form a reliable, sustainable base for city growth and development operating as part of complex ecosystems processing water and waste whilst generating energy to support other activities.This proposition investigates the possibility of inserting decentralised infrastructure within existing green spaces in the city of London. Economic, ecological and social constraints become drivers for architectural design taking a particular test site, Gordon Square in Bloomsbury, to model a fragment of a city-wide masterplan. The brief pursues total resource recovery, where waste products from different systems benefit others by becoming useful inputs. This encompasses district heating to local buildings from the treatment of wastewater, to the propagation of exotic fruits [and even fresh fish] on site for sale in a localmarket. Ideas of localism underpin this decentralised thinking within broader environmental concerns. Civic infrastructure can once again make significant places for city-dwellers’ enjoyment whilst contributing to the broader public understanding of science. Tutor(s)