Fresh groundwater, once taken for granted, is scarce in many parts of the world. Increasingly, freshwater scarcity plagues portions of the USA. Once considered a “waste” to be discharged as conveniently and economically as possible, sewage effluent increasingly is being looked at as a resource to be reclaimed and reused.
Commercial and industrial “non-contact” uses of treated wastewater effluent is not new. Many industrial and commercial facilities, particularly located near municipal wastewater treatment plants, use effluent geothermally, industrially and for irrigation. In some locations where hydrogeologic conditions allow, treated effluent is injected into the ground as a component of long-term aquifer management. Aquifer Storage and Recovery is growing in feasibility as costs lessen, but has been an understood resource management option for some time.
What is new, at least in the United States, is that advanced treatment technology has broadened thinking in terms of the safety, affordability and wisdom of actual, direct potable reuse of sanitary wastewater. Cities in Florida and California are reacting to population growth, periodic droughts and limited freshwater resources by looking intently at direct potable reuse of their sanitary wastewater.
Getting past the psychological “ick factor” is no easy thing, and removal of all pollutants is not inexpensive, but an increasing number of places are at least considering this approach to sustainable water resources management. Water consumers and regulatory agency officials both wonder about the health and safety of such approaches, despite a growing body of technical data that suggests that wastewater can be processed, filtered and disinfected to re-achieve the compliance standards of the Environmental Protection Agency (EPA) for drinking water.
The big question is will this reclaimed, processed and filtered wastewater have users willing to drink it? It already does.
- In Hillsborough County, Florida a pilot program validated that direct potable reuse was biologically and chemically safe to drink. While the water is not being piped to drinking water customers currently, it is being used as part of an aquifer storage and recovery project, to help protect vulnerable aquifers form saltwater intrusion.
- A San Diego-based craft-beer company uses recycled water to create a “full circle” brew.
- Orange County, California, with large water demand and frequent and recurrent droughts, increasingly turns to reuse, both for non-potable demands (since the 1970s) and more recently to help meet potable demands too. Other parts of California now plan to follow suit.
- Tucson Arizona plans to capitalize on new State regulations permitting the direct reuse of treated municipal effluent as drinking water. Officials there have been finding that stringent treatment requirements commonly result in drinking water of better overall quality than if withdrawn from wells, rivers and other “pristine” sources. Direct reuse also is considered a means to ease chronic over-reliance on the Colorado River.
Negative public perception continues to be an issue plaguing direct potable reuse initiatives. Activists and others express public disgust and fears of contagions. In the months and years to come, public relations and outreach will be at least as important as continuing technological improvements in filtration and treatment. continue to occur.
ALWI continues to be a regional leader in evaluating circumstances and opportunities appropriate for treated wastewater reuse, as a potable water source or otherwise. Presently our municipal clients supply treated wastewater for use in industrial processing, non-contact heating and cooling, and commercial irrigation. We expect the demand for treated effluent to grow.