More than a few dystopian fantasies depict a future in which humanity’s water supply derives from recycled human waste. As Frank Herbert imagined it in his 1965 novel “Dune“ — now a much-anticipated fall 2021 blockbuster — the humans inhabiting a dessicated, rainless planet must wear “stillsuits”— a rubbery second skin that captures sweat, urine and feces and recycles them into drinking water.