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The CEEF (Closed Ecology Experiment Facilities) was constructed for collecting data on carbon transfer from the atmosphere to crops, livestock and humans by conducting material circulation experiments, including the habitation of humans and animals and growing crops which supply food and feed, within a closed environment. The main objective of the CEEF project involves understanding the transfer of radiocarbon in the environment via experiments using stable carbon isotopes. On the other hand, the project is also a good example demonstrating human life in ecosystem material circulation. Many people visited and toured the CEEF and the project has been introduced by the media. The candidate inhabitants, who were selected for the project following medical and psychological testing, are called “eco-nauts”. The CEEF project was introduced and eco-nauts participated in events with the intention of educating the public on the human impacts on an ecosystem made by a science museum.

The Closed Ecology Experimental Facilities (CEEF), is designed to simulate material circulation, and is an artificial closed agricultural ecosystem with plants, humans and animals. The first seven-day air circulated confinement experiments using the CEEF were conducted three times. The experiments included psychological monitoring of two crew members named “Eco-nauts”. Even though there was some trouble with the CEEF regarding the atmospheric gases (which one of the Eco-nauts discovered himself), all three experiments were completed without critical problems and both Eco-nauts maintained a stable psychological status. Through the experiments, it was found that the interior environment of the CEEF could fluctuate within short time periods, and that frequent monitoring by the instantaneous and sensitive Face Scale Test allowed scoring of the Eco-nauts' response to such fluctuations.

The Closed Ecological Experimental Facilities (CEEF), designed to simulate material circulation, is an artificial closed agricultural ecosystem with plants, humans and animals. In the experiments starting from FY2005, habitants referred to as eco-nauts will be exposed to complex workloads and various CEEF environmental factors, which may influence their physio-psychological state, and lower their performance. Therefore, preliminary experiments were conducted on the workload-matched (11.1h work, 168h, airlock open) and the environment-matched condition (6.9h work, 24h, air circulation) to monitor physio-psychological changes. As a result, both experiment types were conducted as scheduled without any major problems, and no serious physio-psychological disorders were observed in the eco-nauts. One week closed habitation experiments will be performed as a preliminary step toward much longer (max. 4 months) experiments.

Rating of daily amounts of CO2 and O2 exchange of crops, animals and humans to be involved in the long-term habitation experiments using the Closed Ecology Experiment Facilities (CEEF) were carried out. Daily amounts of the CO2-absorption and O2-generation of crops including rice, soybeans and other 27 vegetables were estimated from data obtained from a sequential crop cultivation experiment conducted from August to December of FY2001. Daily amounts of O2-consumption and CO2-expiration of two female Shiba goats to be involved were estimated based on gas exchange determination conducted in FY2002. Daily amounts of CO2-expiration and O2-consumption of two persons to be involved were estimated based on correlation between respiration rate and heart rate, heart rate data during the simulated habitation in the CEEF and a tentative work schedule.

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.

A unique recovery system for NaCI (salt) from urine, which consists of electrodialysis (ED) and crystallization processes is proposed. The possibility of the mineral recovery included in urine is shown in a previous report. To improve the purity of the produced salt, pH control is needed as a pretreatment. By controlling pH of the feed solution to about 10, multivalent ions such as Ca2+ and Mg2+ are crystallized as phosphate solids which can be separated by filtration. As well as raising the NaCI purity, this controls scaling b y multivalent ions.

We propose a new recovery system for NaCl from human urine. The system has an electrodialysis (ED) part and a crystallization part. Separation and concentration characteristics of the system are discussed for fundamental experiments of the ED and crystallization parts. Concentrated NaCl-KCl mixed solution is obtained using the ED process from simulated oxidized urine and sweat which include Ca2+ and S042- ions. Then, the crystallization process is used to separate about 80% of the NaCl from the ED treated solution. The experimental studies indicate that the mineral recovery system we proposed can recover NaCl from waste water of a CEEF.

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.

Recycling human and animal excreta is an important part of the proposed Closed Ecology Experiment Facility (CEEF) in Japan. This paper introduces a conceptual design for the waste collection and transfer system. Mineral-rich wastes such as urine and wool grease must be separated from other wastes to recover the minerals. Solids and liquids also require separate handling methods. Our design uses inclined conveyer belts to separate feces and urine. A fluorocarbon polymer coating prevents wastes from sticking to the belt. In-line freezers are used to solidify liquid wastes and retard premature decomposition. A summary of available data on animal excreta is included, but there is a distinct shortage of useful information. This data is insignificant for usual biology or animal husbandry, but is essential for designing the self-contained environment.