Life Cycle Assessment (LCA) 

I use the current human waste management on the ISS as the LCA benchmark. The condition is defined according to the lunar outpost mission, in which there will be 4 crew members rotating every 6 months.

Benchmark

The human waste management on the International Space Station (ISS)

Scope

The evaluation focus on the disposable products which go into the process in a year. However the following variables are excluded since the information is inaccessible or irrelevant to the project:

- Product for air filtration

- Refill Water Pouch

Functional Unit

Impact

Waste in human waste process/4 crewmembers-year (lb)

The Current Process 

The Simplified Flow Diagram

LCA process tree - the waste system

LCA process tree - input materials

Impact Matrix

The new process
Comparison of Okala score

*

Note:

The actual input and output from Torrefaction Processing Unit (TPU) and Heat Melt Compactor (HMC) still need more information and study to precisely conduct LCA and Okala score.

*Replaced with related process to roughly measure the scale of the impact since the item is not included in Okala Factor.

*

*

Conclusion

The Okala score of the new solution has demonstrated a huge decrease in environmental impact. This improvement resulted from the effective processing of Torrefaction, and the possibility of applying repurposed human waste product in lunar habitat.

 

The new closed-loop process has eliminate the needs for storage canisters and the trip for destructive re-entry to Earth, which the impact mainly came from.

  • Grey Instagram Icon
  • Grey LinkedIn Icon

All works © 2019 by Shu Ou