Water Quality and Total Microbial Load: A Double-Threshold Identification Procedure Intended for Space Applications

Area of Science:

• Microbiology
• Space Science
• Environmental Science

Background:

• Long-duration space missions necessitate self-sufficient spacecraft with robust water management systems.
• Current water monitoring methods are insufficient for the demands of extended space exploration.
• Contamination risks in recycled or stored water pose significant threats to crew health.

Purpose of the Study:

• To evaluate culture-independent microbiological methods for real-time water quality monitoring in space.
• To establish new reference values for total microbial load in space-based water systems.
• To enhance crew responsiveness to potential water contamination events.

Main Methods:

• Analysis of total microbial load using early-warning techniques: Heterotrophic Plate Count (HPC), ATP-metry, quantitative Polymerase Chain Reaction (qPCR), and flow cytometry.
• Testing across diverse water sources with varying contamination levels (chlorinated/unchlorinated tap water, groundwater, river water, wastewater).
• Application of a data-driven double-threshold identification procedure for microbial load assessment.

Main Results:

• Established new, data-driven reference values for total microbial load, suitable for space applications.
• Demonstrated the efficacy of selected early-warning techniques in assessing microbial contamination.
• The proposed approach enables immediate alerts for microbial load peaks.

Conclusions:

• The developed methodology provides an effective system for in-flight water quality monitoring.
• This approach enhances crew safety by enabling rapid response to contamination.
• The findings support improved water management for both space missions and terrestrial applications.