Status of the Small Water Recovery Unit Breadboard - Performance Evaluation

This paper will describe the results and conclusion of the breadboard design of a small water recovery unit which utilizes a combination of Forward Osmosis (FO) and Membrane Distillation (MD) for processing urine and condensate. We will summarize the main results, design challenges and improvement strategies of the developed system.

The design of the enhanced water recycling system for WRU breadboard is based on an open loop triple circulation system with a two stage filtration. The first stage, which marks the main filtration and contaminant rejection stage, is based on water extraction by using the Aquaporin Inside™ technology. The water purification and draw solution re-concentration is then realized in the recovery stage using direct membrane distillation.

The WRU is designed to be a fully operable system containing all necessary pumps, pipes and measurement components. The filtration processes and all components were chosen to be lightweight and easy to operate with as high a water recovery yield as possible. The only external connection to the unit are power and the supply of contaminated water. The only components that have to be exchanged in to be defined intervals are the membrane elements.

This paper will describe the experiments that were performed with the complete unit including synthetic and real urine test runs. We will focus on urea rejection of the different stages and water quality of the final product.

Danish Aerospace Company and Aquaporin have tested the patented Aquaporin Inside™ water membrane in space on ISS in 2015 and 2016. Now, the aim is to use this technology to develop a filtration unit to recover potable water directly from wastewater made up of urine and condensate. If development turns out successful, the system will be evaluated for its suitability for 90 days missions in the Cislunar environment beyond LEO.