Mark Nelson, PhD, has worked for several decades in closed ecological systems research. As one of eight brave souls enclosed in the pioneering Biosphere 2 experiment for two years in 1991-1993, Nelson learned fi rst hand how essential the proper use of human waste is to the health of the planet. This realization, combined with his lifelong love aff air with constructed wetlands, led to the development of Wastewater Gardens, an ecological way to treat human waste and preserve water quality.