Human urine... is full of the same nutrients that plants need to flourish. It has a lot more, in fact, than Number Two, with almost none of the pathogens...At first, collecting their urine in a jug was “a little sloshy,” Ms. Lucy said. But she was a nurse and he was a preschool teacher; pee didn’t scare them. They went from dropping off a couple of containers every week or so at an organizer’s home to installing large tanks at their own house that get professionally pumped out...Toilets, in fact, are by far the largest source of water use inside homes, according to the Environmental Protection Agency. Wiser management could save vast amounts of water, an urgent need as climate change worsens drought in places like the American West...Chemical fertilizer is far from sustainable. The commercial production of ammonia, which is mainly used for fertilizer, uses fossil fuels in two ways. First, as the source of hydrogen, which is needed for the chemical process that converts nitrogen from the air into ammonia, and second as fuel to generate the intense heat required. By one estimate, ammonia manufacturing contributes 1 to 2 percent of global carbon dioxide emissions. Phosphorus, another key nutrient, is mined from rock, with an ever dwindling supply.