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In CEEF(Closed Ecological Experiment Facility) which is the first Japanese CELSS experiment facility, the ammonia and ammonium nitrate production system is a nitrogen fixation system as a part of nitrogen circulation system. Nitrogen and water which are input materials to the system are processed to produce ammonia water and ammonium nitrate solution as raw materials of fertilizer for plant cultivation. The design basis of the system is to convert 125g/day of nitrogen to ammonia and ammonium nitrate based on the amount of one person's metabolism. Experiment of the system has been carried out and we have studied characteristics of the system.

Nitrogen Fixation Systems(NFS) suitable for plant cultivation in a closed environment have been studied through experimental verification. The system is composed of physico-chemical processes only. Nitrogen gas and water are fed into the system as raw materials,and ammonia and ammonium nitrate solution are produced as final products, which are utilized as main fertilizers in plant cultivation. Each elemental chemical process in NFS is selected with regard to unique design criteria concerning safety, energy effectiveness, compactness and reliability. An experimental apparatus for important unit processes has been made for the purpose of verifying process data. A detail design for nitrogen fixation facilities, planned for construction as the first Japanese CELSS laboratory, was carried out.

In the closed environments, removal of trace contaminants generated from persons, animals, and plants is important function to keep the environment below the allowable level. We conducted the fundamental tests in order to confirm design of TCCA (Trace Contaminants Control Assembly) for Closed Ecology Experiment Facilities (CEEF), and obtained the following results; 1) The palladium-on-alumina catalyst is suitable for CO, CH4, C2H4 conversion at temperature lower than 400°C. 2) The alkali impregnated AC (activated charcoal) is effective for NO2, SO2 removal and prevents catalyst poisoning from SO2. 3) The active-desorbing conducted by hot air blow-throw an AC is effective for C2H5OH, CH2Cl2 desorbing. We discuss the fundamental test and design conditions for TCCA.

A conceptual study for a computational simulator of material circulation in a CEEF was performed. CELSS such as the CEEF (Closed Ecology Experiment Facility) which is under construction in the Institute for Environmental Sciences have many physico-chemical devices. To simplify their programming, many physico-chemical devices were classified into several function groups using C++, a specially designed programming language to support the object oriented programming technique. Based on the classifications, the simulation software was made and the simulation was performed. The simulation results predict that stable operation of CEEF can be obtained.