March 2007, Vol. 19, No.3

Waterline

Super Slurper: From Laboratory Bench to Library Sh

Super Slurper, a cornstarch-based super-absorbent polymer invented by U.S. Agricultural Research Service (ARS; Washington, D.C.) scientists more than 30 years ago, might have applications useful to those in the water and wastewater field.

“[Researchers] were looking at new uses and modifications of starch, and they stuck on polyacrylamide essentially — a synthetic polymer — and when they did that, they discovered it could hold three or 400 times its weight in water,” Bill Orts said of fellow lab researchers. Orts is a research leader in the ARS Bioproduct Chemistry and Engineering Research Unit in Albany, Calif.

Currently, Super Slurper is receiving commercial attention, thanks to Nicholas Yeager, president of Artifex Equipment Inc. (Penngrove, Calif.), a company specializing in book and document restoration. This fall, Yeager’s company began mass-producing Zorbix, a sheetlike product based on Super Slurper that can dry out waterlogged library materials before destructive molds take hold.

But beyond books, Yeager is currently researching other applications for Zorbix.

“We are in the early stages of this product,” Yeager told Water Environment & Technology (WE&T). “We’re doing a couple of tests right now on free-flowing water, as opposed to water in books.”

One potential use is to wrap the absorbent product around pipes, or to use it beneath and around pipes where condensation may occur.

“Because it’s such an effective desiccant, we’re trying different ways of using it,” Yeager said.

Zorbix’s commercialization is the latest chapter in a storied history of Super Slurper spin-offs that followed an ARS patent on the starch polymer in 1976. Among those spin-offs were disposable diapers, wound dressings, fuel filters, and seed coatings.

To better meet demand since debuting Zorbix, Artifex has obtained automated equipment capable of making thousands of the sheets per hour.

“It’s just great sponge material,” Orts told WE&T. “What we think is even more exciting, is what we could use it for beyond books.”

For more information, see www.ars.usda.gov/is/pr/2003/030922.htm.

Water-Saving Methods Often Are Myths, Study Says

A scientific study of outdoor water use has found that some water-saving ideas could be urban myths that are wasting thousands of liters each day. The project by the Cooperative Research Centre for Irrigation Futures (Queensland, Australia) is headed by Basant Maheshwari, an associate professor at the University of Western Sydney (Australia).

The study of 50 home sites in the Sydney metropolitan area found that a lush green lawn may not always be the biggest water guzzler in the yard — instead it’s the plants in the garden beds, states a university press release.

“It was a surprise to find two-thirds of the total irrigation water used in the home goes on the garden, but it covers only half the total area of the yard,” Maheshwari said. “This suggests garden areas are substantial water users and need to be targeted for improved watering practices to make a significant decrease in our water consumption.”

The study also found that using water-wise small gardens as water savers could be an urban myth. Homeowners in the study frequently overirrigated smaller areas of less than 50 m2 (538 ft2). Maheshwari explained that most people “don’t have a clear understanding of the water needs of their gardens, with plants receiving on average three times the water they can actually use.”

Many households install automatic watering systems, believing they will deliver water to plants more effectively and efficiently, the press release states, but the study shows this also could be wasting thousands of liters of water. Poor design, installation, and maintenance of these systems keep them from being cost-effective.

Maheshwari said that an inspection service for home irrigation systems issuing special “waterworthiness” certificates — similar to inspection and emissions certificates for cars — may be one way to control the waste.

See the full report at www.irrigationfutures.org.au/news.asp?catID=9&ID=270.

California Wine: Complex and Smooth With Hints of Salmon

The secret ingredient in California wine? Dead fish, according to a University of California–Davis (UC Davis) news release.

New research shows that the salmon that die naturally in California’s Mokelumne and Calaveras rivers contribute significantly to the growth — and likely the quality — of wine grapes raised nearby.

Using a combination of their own new studies and other researchers’ earlier findings, fisheries biologist with East Bay Municipal Utility District Joseph Merz and California fish authority Peter Moyle of UC Davis examined what happens after chinook salmon incorporate the rich chemistry of the northern Pacific Ocean (carbon, nitrogen, phosphorus, and more) into their body tissues, then carry it upstream in fall and winter to their inland California spawning grounds.

By tracing the movement of elemental “fingerprints” called nitrogen isotopes, the scientists found that when the salmon die upstream after spawning, natural scavengers move the marine-origin nutrients into the terrestrial food chain — either through their wastes or by dropping fish carcasses onshore.

Merz and Moyle recorded 14 species of animals feeding on salmon carcasses, including turkey vultures, raccoons, river otters, rats, coyotes, and even deer.

Before long, the nutrients travel through soil and water into wine grapes being grown commercially along the riverbanks, according to the news release.

“What we found is that the grapes close to the river get up to 25% of their nitrogen from salmon,” Merz said. “In wine making, nitrogen affects yeast growth and sugar fermentation. No doubt some of the best California wine has salmon in it.”

While their results should enliven the table talk over dinners of wild salmon and pinot noir, Merz and Moyle say there’s more to it.

“Our study indicates that managing regulated rivers for salmon has benefits far beyond simply providing fish for fishermen,” they write. “The marine-derived nutrients of salmon can positively affect both natural riparian systems and agricultural crops, with considerable economic benefit.”

A report on the study, “Salmon, Wildlife, and Wine: Marine-Derived Nutrients in Human-Dominated Ecosystems of Central California,” is published in the June 2006 issue of the journal Ecological Applications, available online at www.esajournals.org.

    

ARS Seeks Partner for New Environmentally Friendly Fertilizer

The U.S. Agricultural Research Service (ARS; Washington, D.C.) is seeking a company to license a new, environmentally friendly, slow-release fertilizer for lawns, turf, and other crops.

This new fertilizer technology can reduce the potential for leaching of nutrients into groundwater, streams, and rivers by as much 97% for phosphorus and 84% for nitrates in greenhouse studies, according to an ARS news release.

Slow-release fertilizers currently on the market typically work by applying a sulfur or polymer coating to fertilizer granules. The coating wears away slowly, delaying the release of fertilizer. But once the coat is gone, the remaining fertilizer becomes available in a fast cascade.

In contrast, the ARS slow-release system is based on ion-exchange mechanisms that more closely mimic natural soil processes, which gives the new technology a more consistent release over time.
ARS is seeking a cooperative business partner to license the technology and develop it into commercial products — especially one for use on lawns and turf, which tend to be major contributors to nutrient runoff and leaching.

The fertilizer system also can be used on almost any crop and could be customized to the specific needs of a crop throughout its life cycle, according to co-developers Robert E. Sojka, director of the ARS Northwest Irrigation and Soils Research Laboratory in Kimberly, Idaho, and former ARS soil microbiologist James A. Entry.

For more information, see www.ars.usda.gov/research/patents/patents.htm?serialnum=11504401. For ARS licensing information, see www.ars.usda.gov/business/docs.htm?docid=768.

Shrinking Ponds Signal Warmer, Dryer Alaska

More than 10,000 Alaskan lakes have shrunk in size or completely dried up between 1950 and 2002, researchers say. According to a University of Alaska–Fairbanks (UAF) news release, Alaska has experienced a warming climate with longer growing seasons, increased thawing of permafrost, and greater water loss due to evaporation from open water and transpiration from vegetation; yet there has been no substantial change in precipitation.

Scientists at the university’s Bonanza Creek Long-Term Ecological Research Program studied 50 years of remotely sensed imagery and conclude that these landscape-level changes in Arctic ponds are associated with recent climate warming in Alaska and may have profound effects on climate and wildlife.

The shrinking of these closed-basin ponds may indicate widespread lowering of the water table throughout low-lying landscapes in Interior Alaska, the researchers write. A lowered water table negatively affects the ability of wetlands to regulate climate, the news release notes, because it enhances the release of carbon dioxide by exposing carbon in the soil to aerobic decomposition.
The study results, explained Brian Riordan, data manager for the Bonanza Creek Long-Term Ecological Research program at UAF, “will allow land managers to stop speculating about possible waterbody loss and begin to address the implications of this loss.”

Waterfowl production could be hugely affected with a lower water table. The Yukon Flats National Wildlife Refuge is used by millions of waterfowl and shorebirds for breeding, which then winter elsewhere, the report explains.

Using black-and-white aerial photographs from the 1950s, color infrared aerial photographs from 1978 to 1982, and digital Landsat satellite images from 1999 to 2002, Riordan outlined each pond by hand.

The main study area was the subarctic boreal region of Interior Alaska, which spans more than 5 million km2 (2 million mi2), bounded on the north by the Brooks Range and on the south by the Alaska Range. To contrast the semiarid, subarctic sites of discontinuous permafrost in Interior Alaska, the researchers also selected study areas in the Arctic Coastal Plain, where the temperatures are much colder, the growing season is much shorter, and the permafrost is continuous, as well as a more maritime site south of the Alaska Range, the press release states.

All ponds in the study regions in subarctic Alaska showed a 4% to 31% reduction in area, with most of the change occurring since the 1970s. The ponds in the Arctic Coastal Plain showed negligible change.
Contact Brian Riordan at ftbar1@uaf.edu, David McGuire at ffadm@uaf.edu, or David Verbyla at ffklv1@uaf.edu.