Some methods for human liquid and solid waste utilization in bioregenerative life-support systems

Area of Science:

• Space exploration technology
• Environmental science
• Agricultural science

Background:

• Bioregenerative life-support systems (BLSS) are crucial for long-term space missions.
• Utilizing human waste is key to increasing the closure degree of BLSS.
• Previous methods for waste processing and nutrient recycling have limitations.

Purpose of the Study:

• To investigate methods for utilizing human liquid and solid wastes to enhance BLSS closure.
• To evaluate two distinct methods for mitigating sodium chloride accumulation in the irrigation solution.
• To assess the feasibility of integrating salt-tolerant plants for waste stream management.

Main Methods:

• Human urine and feces were oxidized using Kudenko's physicochemical method.
• Wheat was cultivated using the oxidized waste products in a soil-like substrate.
• Two salt removal techniques were compared: electrodialysis and cultivation of Salicornia europaea L. (saltwort).

Main Results:

• Electrodialysis removed approximately 50% of sodium from the irrigation solution over nine wheat vegetation cycles.
• Integrating Salicornia europaea L. cultivation with wheat significantly reduced soil-like substrate salinization by NaCl.
• The above-ground biomass of Salicornia europaea L. is a potential food source, and its roots can be recycled.

Conclusions:

• The integration of wheat and Salicornia europaea L. cultivation offers a promising approach to managing waste and reducing salinization in BLSS.
• This dual-crop system enhances the sustainability and closure of bioregenerative life-support systems.
• Further research into optimizing this integrated cultivation system is warranted for future space missions.