Possible risks for the functioning of cyclic processes in the experimental model of a closed ecosystem.

The purpose of the present study is to consider a number of possible risks that may emerge when processed human wastes are involved into mass exchange processes as fertilizers for plants cultivated in the experimental model of the closed ecosystem (CEEM). The problems relating to the disruption of cycling processes in closed ecosystems can be tentatively divided into two groups: the problems that can be rather easily overcome and the chronic problems. Addition of plant inedible biomass to the soil-like substrate (SLS) can result in a decrease in plant productivity because of allelopathic interactions and enhanced growth of microorganisms.

A small closed ecosystem with an estimated portion of human metabolism.

The study describes a small closed ecosystem used to test technologies to be further employed in full-scale manned closed ecosystems. The experimental ecosystem is designed to use a certain portion of human metabolism, which is included in the gas, water, and organic waste loops of the system. In this experimental ecosystem, gas and water loops are fully closed, and the model enables processing of human waste and plant inedible biomass.

Prospects for using a full-scale installation for wet combustion of organic wastes in closed life support systems.

The issue of recycling organic wastes in closed life support systems (CLSS) includes both fundamental aspects of environmental safety of the recycled products and their effective involvement in material cycles and technical aspects related to the structure of the system and the crew's demands. This study estimates the effectiveness of wet combustion of different amounts of organic wastes in hydrogen peroxide under application of an alternating current electric field. The study also addresses the possibility of controlling the process automatically.

The effects of the frequency and waveform of the activating current on physicochemical oxidation of organic wastes.

The study describes the process of organic waste mineralization in an H2O2 aqueous medium activated by alternating current, which is intended to enhance the cycling rates in closed life support systems (CLSS) for space missions. The focus of this study is the relationship between the energy consumption and duration of the process and oxidation level of organic wastes on the one hand and the frequency and waveform of the electric current activating H2O2 decomposition, on the other. Energy consumption and duration of the complete waste mineralization process have been reduced by about 17-18%.