Some Methods for Human Liquid and Solid Waste Utilization in Bioregenerative Life-Support Systems

Abstract

Bioregenerative life-support systems (BLSS) are studied for developing the technology for a future biological life-support system for long-term manned space missions. Ways to utilize human liquid and solid wastes to increase the closure degree of BLSS were investigated. First, urine and faeces underwent oxidation by Kudenko's physicochemical method. The products were then used for root nutrition of wheat grown by the soil-like substrate culture method. Two means of eliminating sodium chloride, introduced into the irrigation solution together with the products of urine oxidation, were investigated. The first was based on routine electrodialysis of irrigation water at the end of wheat vegetation. Dialysis eliminated about 50% of Na from the solution. This desalinization was performed for nine vegetations. The second method was new: after wheat cultivation, the irrigation solution and the solution obtained by washing the substrate containing mineral elements not absorbed by the plants were used to grow salt-tolerant Salicornia europaea L. plants (saltwort). The above-ground biomass of this plant can be used as a food, and roots can be added to the soil-like substrate. Four consecutive wheat and Salicornia vegetations were cultivated. As a result of this wheat and Salicornia cultivation process, the soil-like substrate salinization by NaCl were considerably decreased.

Assessment of composition and toxicity for plants of gases produced during physicochemical processing of human exometabolites as applied to biotechnical life support systems

“…The method of oxidation of human exometabolites was published earlier [2]. As a result such oxidation, a gas mixture is released from the reactor and a mineral solution is formed in the reactor, which, after a special pretreatment, can be used as a fertilizer for growing plants [4]. The gas mix ture released at the stage of electrochemical oxidation was collected in gasholders.…”

Use of human wastes oxidized to different degrees in cultivation of higher plants on the soil-like substrate intended for closed ecosystems

“…Consequently, the SLS appeared to be the basic runoff for Na that might result in its gradual salinization. The solution ways of that problem were investigated in a separate paper (Ushakova et al, 2008). Measurements of concentrations of water-soluble nitrogen in irrigation solutions in the course of plant growth in Treatments 1 and 2 showed that during the first 4 weeks the Table 1 Counts of microorganisms in 1 ml of suspension.…”

The conception of growing first generation-plants in lunar greenhouses

“…This idea is proposed by A. Tikhomirov in cooperation with J.-B. Gros [9,[33][34][35] and developed by Liu et al [20]. Basic characteristics of SLS is a similarity to organogenic fertile soils.…”

“…The idea of composting lunar fines with waste products from a manned base was proposed by Walkinshaw and Galliano [37]. Formation of a protosoil by microorganisms, composting crop residues, for purposively growing plants is being studied [9,[33][34][35]. Nowadays it seems to be practical to integrate in situ terraforming and waste recycling systems with ISRU to accommodate PMLB and to reduce the demand for energy, transfer mass and cost of future exploration [17,18].…”