was subjected to ultraviolet radiation. The processed water is subsequently used as toilet and plant water, though not directly for human consumption. Plants used Plants, or more accurately, the root systems of aquatic plants found to have a filtering effect include bulrush, reed, soft rush and water iris. As explained by Wolverton:When sewage is slowly filtered through an aquatic plant root filter system, complex biological processes take place during wastewater treatment and purification. The symbiotic relationship that is normally established between the plant roots and microorganisms living on and around these roots is very complex and important in the wastewater treatment process... This process not only removes organic chemicals, but is also thought to contribute to the reduction of other polluting substances including pathogenic bacteria and viruses. It has been shown that roots of aquatic plants such as bulrush, reed, soft rush and water iris excrete substances that can either partially or completely kill pathogenic bacteria while not harming beneficial bacterial. The aerobic zone around the aquatic root system can also support, in addition to bacteria, the growth of large numbers of protozoa which feed on bacteria, viruses and particular organic matter. Harvesting drinking water Water suitable for human use was extracted from the condensate from three sources: dehumidifier units, air conditioning, and plant leaves. In fact, plant leaves proved to be a major, consistently reliable source of water vapors. The condensate was run through ultraviolet equipment to ensure its safety. Crop growth Crops were grown in the hydroponic sections of the BioHome, comprising edible plants (squash, corn, sorghum, tomatoes and other organics) and non-edible plants, which were an essential part of the air purification process. Compost made from wastewater treatment plants was used effectively as a growth medium. Air purification The living areas of the BioHome were teeming with plant foliage, the purpose of which was to purify the air of carbon dioxide. As a result of the experiment, it was also found that the plants purified the air of synthetic offgases, such as those emitted from formaldehyde, benzene, toluene and organics. In essence, the plants established and maintained indoor air quality. See also Biosphere 2 BIOS-3 Eden Project Anthroponics Related links PERMANENT - Space Colonies - NASA CELSS Mars Base Zero - an Alaskan CELSS Controlled ecological life support systems Building biology Ecological experiments Hydroponics Human analog missions