News Service


Max Rothschild, Animal Sciences, (515) 294-6202
Tim Ellis, Civil and Construction Engineering, (515) 294-8922
Shih-Wu Sung, Civil and Construction Engineering, (515) 294-3896
Skip Derra, News Service, (515) 294-4917


AMES, Iowa -- A method for converting waste-water sludge into useful biosolid materials and a genetic testing technique for pigs to determine which ones will have the largest litters have won 1999 R&D 100 Awards. Both technologies were developed by researchers at Iowa State University.

The two new R&D 100 Awards brings Iowa State's total to 21 awards since 1984. The R&D 100 Awards, the only awards for applied science and scientists, have been called the "Oscars of applied science" by the Chicago Tribune.

"Winning two R&D 100 Awards shows the relevancy of Iowa State research and the inventiveness of our researchers," said Iowa State University President Martin Jischke. "These awards confirm our standing as a place where research brings results."

Iowa State is one of three universities to win two R&D 100 Awards this year, said Tim Studt, editor of R&D Magazine, sponsor of the award. The other two are the University of Cincinnati and the University of Tennessee. Massachusetts Institute of Technology and the University of California-Los Angeles are among universities that won one award.

The R&D 100 Awards program, now in its 37th year, honors the top 100 products of technological significance that were marketed or licensed during the previous calendar year. All of the 100 award winners will be honored at a banquet in Chicago in September.

Making sludge a useful material
Former ISU civil engineering professor Richard Dague (Dr. Dague died in 1996) developed a temperature-phased anaerobic digestion process that can more efficiently convert municipal waste sludge into environmentally safe and beneficial biosolids. Currently, most waste-water treatment plants in the U.S. employing sludge digestion, use common aerobic or anaerobic tanks for digestion. Three serious problems are usually encountered in conventional digestion processes: low solids reduction, foaming and low pathogen destruction. The resulting sludge is disposed of in landfills, placed on agricultural land, or incinerated, which raises environmental concerns.

The temperature-phased anaerobic digestion process (TPAD) provides a solution to long-standing problems of dealing with waste-water sludge. TPAD is inexpensive and efficient in converting the sludge to biosolids that meet federal (Class A) biosolids standards for unrestricted land application. It also produces a biogas that contains 60 to 75 percent methane as a viable energy product.

The process consists of a two-temperature, two-phase reactor system. The first phase operates at high temperature (135 F) and the second phase operates at a lower temperature (95 F). Conventional anaerobic systems operate only at the lower temperature.

The TPAD process can reduce contamination in waste-water sludge to less than 1 fecal coliform per milligram, a level not obtainable with conventional systems. The sludge is converted into biosolids that can be applied to land as a soil amendment and fertilizer without restrictions. The process also reduces sludge odor and provides an additional 15 to 20 percent reduction in solids compared to conventional methods, said Tim Ellis, an ISU assistant professor of civil and construction engineering.

TPAD has been used in waste-water treatment facilities in Iowa City, Independence, Newton and Waterloo, Iowa; Omaha, Neb.; Duluth, Minn.; and Menasha and Sturgeon, Wis. The technology has been licensed to Anaerobic Biosystems Corp., Ames, Iowa.

Genetic test for pig litter size
The estrogen receptor gene test for improved pig litter size, developed by Iowa State animal geneticist Max Rothschild, is a genetic testing method that helps pork producers increase the size of pig litters by scientifically identifying which females and males have the genes to produce larger litters.

Efficient reproduction is one of the most important economic traits in pork production. But U.S. producers cull 30 percent of their sows because of poor reproductive performance. The ability to identify sows for potential for increased litter size would improve the financial bottom line for producers.

Rothschild and his colleagues have identified a gene that influences litter size. Pigs with both copies of a desirable form of estrogen receptor gene (ESR) have 0.8 to 0.9 more pigs per litter on average than sows without this advantage. Using this test in a 1,000 sow operation could mean a $20,000 increase in income based on average pork prices, Rothschild said.

The ESR gene test, which is based on a simple genetic mutation or DNA polymorphism, allows the first direct selection of individual males and females and can be applied before any animals have their own litters. Conventional methods to improve the genetic ability of sows have relied on statistical methods that can only estimate that some animals are better for larger litter sizes than others.

The ISU researchers have used the ESR genetic marker to identify females capable of producing larger litters and males producing daughters for pork production. The technology is also being used to genetically improve semen and genetically improve breeding females. Use of the new gene test can improve herd genetics, increase pig production efficiency, and possibly reduce animal waste that could harm the environment, Rothschild said.

The technology has been licensed to PIC International Group, Berkeley, Calif.


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