MELiSSA stands for “Micro Ecological Life Support System Alternative” and is a space research program, aiming to develop a bioregenerative life support system for long-term space missions and space habitations for example on Mars.
The MELiSSA project is managed by the European Space Agency and started 30 years ago on a collaborative development program between 14 partners and a large number of supporting sub-contractors and international partners.
Nutrient recovery from urine in space
In the MELiSSA loop, urine is the main target for nitrogen recovery. However, urine has to be converted into a biologically stable solution, before it can be used as a fertilizer. This is what an Eawag PhD project is working on.
A urine treatment chain for space application is proposed based on Eawag’s technology and MELiSSA’s experience. The treatment chain consists of five treatment units (Figure): (1) In the storage tank the urea, which is the main Nitrogen source, is hydrolysed. (2) The removal of the organics takes place in a membrane aerated biofilm reactor (MABR). (3) In a second MABR the urine is nitrified. No base is added, therefore only half of the ammonia is nitrified. (4) Micropollutants are adsorbed in a granular actived carbon filter. (5) In the final step, the urine is disinfected and can be used for the plant compartment of the MELiSSA loop