Water, Water Everywhere: The Ultimate Recyclable

By Iva Fedorka

Many consider water a free, natural resource. But ensuring that enough water will be available and safe to use now costs hundreds of billions of dollars annually for collection, purification, storage and distribution. And recycling efforts to increase supply and reduce costs are stymied by a lack of regulatory clarity at the federal level and concerns raised by occasional contamination crises — including, most recently, high levels of lead found in drinking water in Flint, Michigan, and chemical spills that fouled local drinking water supplies in West Virginia.

Increasing Demand for a Limited Supply

Although the water in oceans is abundant, its salt content makes it undrinkable. Eliminate the water trapped in glaciers and icecaps, and only about 1% of all the world’s water is fresh. A very small portion of that fresh water is found in waterways, with the remainder trapped in soil or aquifers. Regional and local water shortages have become increasingly common: Australia saw severe droughts between 1995 and 2009, and the U.S. has recently experienced droughts throughout the West and Midwest, especially in areas with increasing population. Access to water is also becoming an international issue, with adjoining countries — like Israel and Jordan, and Turkey and Syria — competing for limited resources.

A Battery of Tests to Support Regulations

In the United States, the regulation of water and wastewater is federally mandated by the Environmental Protection Agency (EPA). As part of the Clean Water Act (CWA), the EPA oversees wastewater discharge and treatment, and the National Pollutant Discharge Elimination System (NPDES) issues permits that establish specific discharge limits, requirements for monitoring and reporting, and other measures to ensure that other pollutants do not harm the environment. Under the Safe Drinking Water Act (SDWA), the EPA sets drinking water quality standards and oversees the states, localities and water suppliers that implement them.

The reference manual for all water and wastewater analysis techniques is the “Standard Methods for the Examination of Water and Wastewater.” Published jointly since 1905 by the American Public Health Association (APHA), the American Water Works Association (AWWA) and the Water Environment Federation (WEF), this authoritative resource is currently in its 22nd edition.

Most of the tests it prescribes have been performed for many years, although updated methods and procedures are regularly introduced. Sometimes these result from nominations of substances to the EPA’s Contaminant Candidate List (CCL) for further investigation and possible future oversight.

To fulfill regulatory requirements, approximately 100 substances are measured in ambient water, drinking water and wastewater. Traditionally, water testing has focused on nutrients and microorganisms such as bacteria, viruses, protozoa and parasites. Chemical contaminants may occur naturally or can be introduced by man; these include nitrogen, bleach, salts, pesticides and metal, and compounds found in pharmaceuticals and personal care products, which are not currently regulated by the EPA. Although tens of thousands of chemicals are registered with the EPA, water testing is mandated for only 83 chemicals.

Other tests detect physical contaminants — like sediment or suspended organic materials from soil erosion — that affect the appearance or properties of water. Water may also contain natural or introduced radiological contaminants, like cesium, plutonium and uranium. 

Most water and wastewater testing labs employ equipment and instrumentation, both benchtop and portable, to measure pH, conductivity, dissolved oxygen (DO) and other analytes. Reagents to detect the presence of chlorine, pH, alkalinity, turbidity and other metrics are also typically part of the laboratory operation. Advanced techniques to conduct organic analyses and more specific measurements may require the use of gas or liquid chromatography or mass spectroscopy.

Recycling Requires Rethinking

The costs for testing and treating water and wastewater can be reduced when either is conserved or recycled. Since all water is continuously “re-used” through the hydrologic cycle of precipitation, condensation and evaporation, there may be shortcuts or reuse opportunities yet to be identified within that cycle. “Graywater” from sinks and showers does not constitute “wastewater” and can be used, untreated, for irrigation. “Blackwater” (actual sewage) can be treated to become “reclaimed water” that is suitable for irrigating parks, golf courses, cemeteries and other landscaping. This recycled water is also used for steam turbines or industrial machinery. Some communities have moved all the way to 100% recycling and retain and repurpose all of their wastewater.

A better understanding of exactly how wastewater is treated could increase public support for recycling. When a toilet is flushed, its contents are carried via sewer to a municipal wastewater plant where grates or screens are used to separate any large, solid material from the liquid. The liquids are then placed into a settling tank; smaller solids fall to the bottom and oils rise to the surface. Next, the wastewater moves to an aeration tank where the oxygen helps microbes digest the waste further. After a final settling step, the clarified water is treated with antimicrobial ultraviolet light or chlorine to kill any remaining microorganisms before the water is released. 

“In essence, there is no wastewater, just wasted water,” said Ben Grumbles, president of the U.S. Water Alliance and a member of the Water Science and Technology Board. To Grumbles’ point, successful water recycling programs require a paradigm shift: “used” or “waste” water can become a valuable resource rather than something to dispose of. By removing the step of returning treated wastewater to a stream or lake, handling costs are reduced. Studies have also shown that chemical levels and pathogens in existing water supplies and recycled water are essentially equivalent, and sometimes lower.

“The fact is, people already drink reused water,” said Ken Herd, the Water Supply Program Director for the Southwest Florida district. Municipal water facilities are commonly located downstream from wastewater treatment facilities, creating de facto reuse. But currently there are no national standards for water reuse.

Water management of this kind falls into a gray area somewhere between the Clean Water Act and the Safe Drinking Water Act — leaving the way forward, on a national level at least, anything but clear.