The water cycle is an important part of the controlled ecological life support system (CELSS). It involves the supply of drinking water and plant irrigation water, and the recycling of urine, sanitary waste water, and air condensate water. Using urine and sanitary wastewater for plant irrigation is an effective form of wastewater reuse, but there are three main challenges.
Click here for original story, Space research: Is it feasible to reuse high salinity wastewater as a plant nutrient medium for plant hydroponics?
Source: Phys.org