閉鎖居住実験計画とミニ地球における物質フローの検討 [in Japanese] Plan of Closed Habitation Experiments and Material Flow in Closed Ecosystem Experiment Facilities [in Japanese]
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Closed habitation experiments are to be carried out using Closed Ecosystem Experiment Facilities (CEEF) from 2005 to 2009. Three and six one-week habitations are to be conducted in 2005 and 2006, respectively. The duration of the habitation is to be elongated to two and four months in 2007 and 2009, respectively. 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 and animals, it is necessary to stabilize production of edible and inedible biomass, CO<sub>2</sub> uptake and O<sub>2</sub> production of crops. Although biomass production decreased rapidly during the first five weeks of the 103-days, it was relatively stable during the last ten weeks. Average major foodstuffs in the harvested edible biomass met the requirement of two habitants (named as eco-nauts) although several minor ingredients were insufficient. CO<sub>2</sub> uptake and O<sub>2</sub> production of the crops (150 m<sup>2</sup>) were determined to be 99.9 mol day<sup>-1</sup> and 104.8 mol day<sup>-1</sup>, respectively, based on biomass and ingredient analysis. Total CO<sub>2</sub> and O<sub>2</sub> exchanges of two Shiba goats and two eco-nauts were 63 and 66% of those of the crops, respectively. Flows of carbon and oxygen in the material circulation system including crops, eco-nauts, Shiba goats and physical/chemical part were calculated using these data. The analysis showed that waste processing systems of Closed Plant Experiment Facility and Closed Animal and Habitation Experiment Facility (CAHEF) will proceed solid waste of 307 g day<sup>-1</sup> (10.8 mol C day<sup>-1</sup>) and 651 g day<sup>-1</sup> (25.8 mol C day<sup>-1</sup>), respectively, and that the CO<sub>2</sub> separator of the CAHEF will separate 89.1 mol CO<sub>2</sub> day<sup>-1</sup>. The result obtained in this study confirmed that the crops would serve sufficient biomass and O<sub>2</sub> to eco-nauts and Shiba goats in habitation experiments. CO<sub>2</sub> expired by eco-nauts and Shiba goats also will be served to the crops. However, it will be later than 2008 that all of the CO<sub>2</sub> produced by waste processing returns to the crops, because the completion of integration of waste decomposition systems of the CEEF is planned in 2007. A part of CO<sub>2</sub> will be served from outer source to compensate the lack of CO<sub>2</sub> from the waste processing, and surplus O<sub>2</sub> will be released because of lack of O<sub>2</sub> consumption by the waste processing, by 2007. A result of a rough estimation of water flow in the CEEF conducted based on preliminary experimental data was also shown.
Eco-Engineering 17(4), 231-242, 2005-10-30
The Society of Eco-Engineering