Water woes and wastewater

October 2013 » Departments » COMMENT
Bob Drake

An unusually large number of water-related news stories filled my inbox during the last month, which makes the long-planned "water" focus of the October issue of CE News quite timely.

Uppermost in many minds is the devastating flooding in Colorado that took the lives of at least eight people and caused hundreds of millions of dollars in damage to homes, businesses, roads, and bridges. The cleanup is well underway, but permanently rebuilding many county and local roads to reconnect isolated towns and replacing or repairing an estimated 50 bridges could take years. The Colorado Department of Transportation set an ambitious deadline of Dec. 1, 2013, "to clear, repair, and reconstruct components of the state highway system damaged by the flooding" and established an infrastructure recovery force to oversee the process.

Esri's Disaster Response web page at www.esri.com/services/disaster-response/floods/colorado-flooding-maps provides an excellent collection of impact maps and photos showing the widespread damage.

But most of the month's reports were focused on water supply issues that Coloradans – as well as most of the Western United States and much of the developing world – increasingly face: shortages.

A study by researchers at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder – ironically published in September following the floods – evaluated supplies and demands on freshwater resources for each of the 2,103 watersheds in the continental United States. They found that water supplies are already stressed (demands for water outstrip natural supplies) in 193 of the 2,103 watersheds examined.

An international study (http://inweh.unu.edu/rising-reuse-wastewater) led by Japan's Tottori University and the Canada-based United Nations University Institute for Water, Environment and Health reported that water demands exceed supplies in regions with more than 40 percent of the world's population and in 12 years as much as 60 percent of the world's people may face water scarcity. To cope, researchers predict a rapid increase in the use of treated wastewater for farming and other purposes worldwide. Based on available data, the researchers' premise is that "most wastewater is wasted." For example, in North America, of the estimated 18.7 trillion gallons of wastewater generated each year, 75 percent is treated; however, only about 3.8 percent of that treated wastewater is used.

The good news is that research, presented at a meeting of the American Chemical Society in September, found low levels of pharmaceuticals and personal care products in crops irrigated with recycled wastewater under realistic field conditions. According to Jay Gan, Ph.D., and colleagues at the University of California-Riverside, "These substances do not tend to accumulate in vegetables, including tomatoes and lettuce that people often eat raw. We can use that information to promote the use of this treated wastewater for irrigation."

Additionally, treatment technologies are expanding the application of wastewater reuse beyond irrigation. The WateReuse Research Foundation is sponsoring the 2013 Direct Potable Reuse Specialty Conference, Nov. 7-8, 2013, in Newport Beach, Calif. (www.watereuse.org/foundation/conferences/direct-potable).

The conference will examine regulatory issues, treatment strategies, operational issues, research initiatives, and public acceptance challenges associated with direct potable reuse – blending purified recycled water with other water sources in a potable water pipeline before treatment or distribution.

And speaking of treatment technologies, the activated sludge process is 100 years old this year, as is the first commercially produced gas chlorinator used in a public drinking water system. According to Siemens Water Technologies, chlorination technology "revolutionized the way the world fought water-borne diseases, which killed nearly 30,000 people per year in the 1900s in the United States alone."

Bob Drake

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