Water recycler
A water recycler was a component of the life support systems aboard the 22nd century Klingon transport commandeered by the Arin'Sen.

Three weeks after they escaped from their colony on Raatooras, which had been subjected to the Klingon Empire, their ship's warp drive failed, then eventually their main power went down. They diverted auxiliary power to life support, but they soon lost their food processors and water recyclers. ()

Life support technology