Wastewater treatment is commonly considered as an environmental problem, but it is also a resource problem and an opportunity, both in many poor countries and even in parts of the United States where water is scarce. Generally, the problem is addressed only from the regulatory angle, but regulation is not the only constructive approach to wastewater. There are market-based ways to deal with wastewater that address the environmental problems while finding opportunities for solutions that generate wealth, especially in the use of wastewater for energy. Two interesting examples are: Partially treated wastewater can be coolant for electric power plants; each year 26 billion gallons of “sullage” cool the Palo Verde Nuclear Generating Station in Arizona. Biogas generated in anaerobic digesters can be used for power generation and heating; the Newtown Creek Wastewater Treatment Plant in New York has a 310 million gallon per day capacity, and sells enough natural gas to heat 2,500 to 5,200 homes each year. (source)
While this broader approach may seem far from consumer concerns, it can reduce the costs of wastewater treatment and provide offsetting revenue, thereby reducing power costs and, if the market approach is used more broadly, it may relieve some of the pressure on water resources in dry areas.