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Technical Paper

A Study on the Elements Recycled in the Vegetable Supplying System of a Lunar Base CELSS

Selected vegetables for life support are continuously produced in the lunar farming module. Inedible parts of the vegetables are decomposed and provided as the fertilizer elements for the next vegetables. In this report, contained elements in their inedible mass for recyclingare discussed for each of the four vegetables. Elements and concentration of cultural liquid which are required by each vegetable are surveyed as well. Adjustment of decomposition liquid is discussed in view of transforming inedible vegetable to cultural liquid. Authors are proposing wet oxidization as one of the decomposition methods for these inedible parts. Some adjusting sub-system is necessary here, since elements and their concentration in decomposition liquid is not enough to reproduce vegetables. This report aims to clarify the composition of a vegetable production system for an eight-member
Technical Paper

A Survey of Catalysts for Wet-Oxidation Waste Management Process

A series of experiments to evaluate performance of catalysts for CELSS System Wet-oxidation process has been carried out. Data obtained from the experiments show that the noble metal selected for the catalyst gives a good performance in oxidizing Organic Carbon and Organic Nitrogen. The data also show that a catalyst with certain amount of the metal (wt%) shows maximum efficiency in the oxidation; in addition, a catalyst with a different amount of metal gives good performance in producing high quality fertilizer.
Technical Paper

Considerations of Material Circulation in CEEF Based on the Recent Operation Strategy

In the Closed Ecology Experiment Facilities (CEEF), with integrating the Closed Plantation Experiment Facilities (CPEF) and the Closed Animal Breading & Habitation Facilities (CABHF), closed habitation experiments without material exchange with the outside will be conducted after the 2005 fiscal year. Cultivation experiments of about 30 crops and the integrating test of the material circulation system required for the closed habitation experiments have been performed since 2000 fiscal year. Using data reported in these experiments, material circulation in CEEF is simulated based on the recent operation strategy, and the storage capacity needed for the buffer of an air processing subsystem was estimated. In order for two humans to dwell over 120 days, the storage capacities of the carbon dioxide tank, the oxygen tank, and the waste gas tank in CPEF, and the carbon dioxide tank and the oxygen tank in CABHF are 820 g, 2830 g, 4425 g, 1780 g, and 1792 g, respectively.
Technical Paper

Estimation of Flows of Carbon and Oxygen in the CEEF System Based on Data Collected in a Stable Phase of Sequential Crop Cultivation Lasting More than 100 Days

Closed habitation experiments are to be carried out using Closed Ecology Experiment Facilities (CEEF) from 2005 to 2009. The last target of duration of closed habitation is four months. Preliminary study and testing have been conducted in order to start the closed habitation experiments. In 2004 as the last year of the preliminary test phase for the 2005–2009 experiments, periodical harvesting from staggered cultivation of 23 crops including rice, soybean, peanut, and sugar beet was continued during 103 days. In order to balance with metabolisms of humans (named as “eco-nauts”) and animals, it is necessary to stabilize production of edible and inedible biomass, CO2 uptake and O2 production of crops. Although biomass production decreased rapidly during first five weeks of the 103-day period, it was relatively stable during last ten weeks. Average major foodstuffs in the harvested edible biomass met the requirement of two Eco-nauts although several minor ingredients were insufficient.
Technical Paper

Experimental Study on Ammonia and Ammonium Nitrate Production System in a Closed Ecological Experiment Facility

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.
Technical Paper

Mineral Recovery Systems for Humans in a CELSS

The recovery of important minerals, salt (NaCI) and potassium (K), in a closed system, namely CELSS is discussed. NaCI is needed for humans, but is potentially harmful to plants. Salt is recovered after wet oxidation of urine. Since Na and K have similar chemical and physical properties, their recovery or separation may require sophisticated methods. Na, CI and K ions are separated from other ions by electrodialysis with univalent selective ion-exchange membranes and then NaCI is obtained separately by a crystalization process. Preliminary experiment on crystalization of NaCI-KCl mixed solutions showed a good separation result.
Technical Paper

Paper Production in an Advanced Life Support System (ALSS)

This paper introduces a concept and a design to supply paper products for an earth based Advanced Life Support System (ALSS) test bed and it shows some results of paper production trials on the ALSS using inedible biomass. Rice plants (i.e. straw and roots), and soybean stems were pulped by boiling and/or alkali soaking and a mechanical processing method. Paper could be produced from both and exhibited different characteristics. Paper with quality suitable for hygienic tissue could be obtained and very absorbent paper was also possible. A rapid pulping method without a chemical process was also investigated. A potential for reducing chemical consumption, liquid waste and labor cost of paper production in the ALSS was demonstrated.
Technical Paper

Performance Test Data of Wet Oxidation Plant for CEEF - CEEF: Controlled Ecology Experiment Facilities

This waste management process must be capable of treating the various wastes generated within Controlled Ecology Experiment Facilities (CEEF) and operate effectively in and environment in which carbon, oxygen, nitrogen, salts, and other important minerals, exit. The catalytic Wet Oxidation Process (W/O Process) is regarded to be the most feasible candidate process for such waste management. This paper clarifies the performance data and the design data of the actual device. By applying these comparison data, for example, water balance, insoluble part balance, organic part balance, and inorganic balance for CEEF, we were also able to confirm the usefulness and applicability of the actual Wet Oxidation Device.
Technical Paper

Plant Nutrient Solution Production Subsystem and Mineral Recycling in CEEF

In the Closed Ecology Experiment Facilities (CEEF), waste materials such as plant inedible parts, feces and urine of animal and human, and garbage are to be decomposed to inorganic materials by a physical and chemical (P/C) process; Wet Oxidation (W/O). It is known that significant part of nitrogen (N) in the waste materials is reduced to gaseous nitrogen (N2) through W/O process. There is also some deposition of minerals such as iron (Fe) and phosphorous (P) through W/O process. Nitrogen Fixation Subsystem (NFS) produces ammonia (NH3) which is one of end products of NFS, from N2 separated from module air and hydrogen (H2) derived from electrolyses of water, and also produces nitrate (HNO3) from a part of the NH3 and oxygen (O2) derived from electrolyses of water. As another end product of NFS, ammonium nitrate (NH4NO3) is produced from the HNO3 and a part of the NH3.
Technical Paper

Preliminary research on Energy Metabolism of Candidate Animals in Closed Ecology Experiment Facilities (CEEF)

The basal metabolism of the Candidate Animal is mainly on energy metabolism that was estimated for future animal breeding in CEEF as preliminary research. The amounts of gas exchange in the respiration and heat production of the Shiba goat (native Japanese goat) were analyzed to predict energy and material flow of the animal breeding system in the Closed Ecology Experiment Facilities (CEEF). Experimental animals were fed Timothy hay or inedible parts of rice cultivated in CEEF. The feces and urine were collected during the 7-day metabolism measurement period after a 2-week preliminary breeding period. The O2 consumption, CO2 production, and CH4 production were measured by a mass spectrometric respiration gas analysis system on the 7th day of the metabolism measurement period. Heat production was also obtained from these data. O2 consumption, CO2 production and CH4 production were 100.3 - 153.8 L, 127.2 - 174.0 L and 5.7 - 10.8 L per day (at 0°C, 0.101MPa), respectively.
Technical Paper

Study for Minimizing of Toxic Gaseous Waste in Wet Oxidation Process

Compared with other applicable processes such as incineration, the catalytic wet oxidation process is considered to be the most practically applicable waste treatment process for the CELSS. In this report, the quantity of carbon monoxide generated in the wet oxidation process is identified and a measure for carbon monoxide minimization is discussed. As a result of a bench test, it became apparent that a non-negligible quantity of carbon monoxide could be generated in the catalytic wet oxidation process. However, it can be expected that this CO content will be reduced to a safe level by applying the wet oxidation process catalyst reactor to CO oxidation.