title: Solid waste processing in a CELSS:  nitrogen recovery.
abstract: Life support technologies are being developed for long-duration space missions at NASA Ames Research Center as part of the Controlled Ecological Life Support System (CELSS) Program.  The primary goal of the CELSS Program is to develop small-scale ecological systems, a CELSS, that mimic ecological systems on Earth.  This small-scale replica CELSS can provide all of the necessary life support functions and recycle nearly 100% of the waste products.  A CELSS will use plants to purify air, clean water, and generate food for a human habitat.  Human and plant waste products will be converted to useful products and reintroduced into the plant and human habitats for consumption.  Both physical/chemical and biological waste-processing systems may be utilized to recycle waste materials.  Recovering nitrogen from waste products is a major concern because nitrogen is an important nutrient for plants and humans.  This article will outline plant selection requirements and waste-processing requirements, characterize waste streams, and discuss the potential physical/chemical waste processors used to process the wastes and the fate of nitrogen as a result of the process employed.
authors.affiliation: Lockheed Martin Engineering & Sciences, NASA-Ames Research Center, Moffett Field, CA 94035-1000, USA.
authors.forename: S
authors.initials: S
authors.lastname: Pisharody
authors.forename: B
authors.initials: B
authors.lastname: Borchers
authors.forename: G
authors.initials: G
authors.lastname: Schlick
mesh_terms: D018533:Biomass; D018504:Ecological Systems, Closed; D004783:Environmental Microbiology; D006801:Humans; D017745:Incineration; D008021:Life Support Systems; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D010084:Oxidation-Reduction; D018521:Plant Physiological Phenomena; D010944:Plants / Q000378:metabolism*; D018505:Waste Management / Q000379:methods*; D014866:Waste Products; D014867:Water
chemical_list: D009566:Nitrates; D014866:Waste Products; D014867:Water; D009584:Nitrogen