AUDREY D. LEVINE UNIVERSITY OF SOUTH FLORIDA, TAMPA TA K A S H I A S A N O UNIVERSITY OF CALIFORNIA, DAVIS
Society no longer has the
F
luxury of using or water supplies to be sustainable, water only once. the rate at which water is withdrawn from water sources needs to be in balance with the rate of renewal or replenishment. At the same time, water quality must also be sustainable or recoverable. In nature, precipitation replenishes surface water supplies and recharges groundwater. However, urbanization, agriculture, dams and reservoirs, and other shifts in land-use patterns are altering the rate, extent, and spatial distribution of freshwater consumption and replenishment. Therefore, water withdrawn for societal needs must also be considered a source in the sustainability equation.
JUNE 1, 2004 / ENVIRONMENTAL SCIENCE & TECHNOLOGY ■ 201A
© 2004 American Chemical Society
FIGURE 1
Annual water use
(a) The amount of water withdrawn for agriculture, industry, and municipal applications around the world has grown steadily over the past century. Reservoir water use refers to evaporation. (Adapted with permission from Ref. 3.) (b) The amount of water used for potable and nonpotable applications varies. Data from Ref. 25.
(a)
Historically, after water was used for societal needs, it was labeled as sewage or wastewater and treated for discharge into receiving water or for land disposal. During most of the 20th century, wastewater treatment emphasized pollution abatement, public health protection, and prevention of environmental degradation through removal of biodegradable material, nutrients, and pathogens. However, over the past few decades, people have recognized the potential for recovering water from wastewater. In fact, in many parts of the world, using water only once is no longer an option. In this article, we summarize how water reuse has emerged as a vital component of sustainable water