ABSTRACT
A new sustainable urban living design that recovers, recycles, and reuses nutrients lost in the human and animal waste streams is needed. Conservation and reuse must include freshwater as well as nutrients because both limit the available food and biofuel supply. Limits to key natural resources will force substantial design changes in food and energy production in order to support sustainable urban living in the US West and Southwest. Green solar energy captured in algae represent an agriculture of abundance based on cheap natural resources that will not run out, sunshine, wastewater, and carbon dioxide. Algae are far more productive than other biofuels sources because algae do not put energy into producing roots, stems, trunks, and leaves because they grow in water. Algae are energy positive because the energy cost of algaculture and downstream processing is less than the energy yield of the algae oil, which is produced using solar energy in the process of photosynthesis.
