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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.

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.