Developed by ISU engineers, a method for converting wastewater sludge into useful biosolid materials has been recognized as one of the 100 top technologies of 1998. Often called the “Oscars of Invention,” the R&D 100 Awards honor the 100 products recognized by R&D Magazine as the year’s most technologically significant new products and processes.

Former CCE Professor Richard Dague (who died in 1996) and CCE Assistant Professors Wu Sung and Tim Ellis developed a temperature-phased anaerobic digestion process (TPAD) that can more efficiently convert municipal waste sludge into environmentally safe and beneficial biosolids. The TPAD provides a solution to long-standing problems of dealing with wastewater sludge.

The process can reduce contamination in wastewater sludge to levels not obtainable with conventional systems. TPAD is inexpensive and efficient in converting the sludge to biosolids that meet federal biosolids standards for unrestricted land application. The process reduces sludge odor and also produces a biogas that contains 60 to 75 percent methane as a viable energy product. It is the first anaerobic digestion process that does not produce biosolids that have to be incinerated or disposed of in landfills.

TPAD has been used in facilities in four states. The technology has been licensed to Anaerobic Biosystems Corporation of Ames.


MSEs discover second-hardest known substance

Two Iowa State researchers made a gem of a discovery while tinkering with an unlikely material —it’s the second-hardest bulk substance after diamond. MSE Associate Professor Alan Russell and MSE Ph.D. student Bruce Cook, both associate scientists at the U.S. Department of Energy’s Ames Laboratory, made the discovery.

By introducing a small amount of silicon and titanium diboride into an alloy of aluminum, magnesium and boron, they created a material slightly harder than cubic boron-nitride, the material now ranked second. They hope that experiments with other additives will make
it even harder.

The researchers tested samples of the alloy on several different instruments, all of which measured its hardness slightly higher than cubic boron-nitride’s, but considerably lower than diamond’s hardness.

The aluminum-magnesium-boron compound is expected to be considerably less costly than the other two materials, which could generate huge savings for manufacturers that use these types of materials in abrasives and cutting tools for grinding and machining applications.

“The fact that industries are willing to pay that price for cubic boron-nitride gives some insight into what a critical industrial process this is,” said Russell. “Cutting iron and steel is an enormous part of the U.S. manufacturing economy.”

Cook, who leads the research, discovered the hardness of the aluminum-magnesium-boron compound by accident. He was researching its thermoelectric properties in 1992 when he discovered that he couldn’t cut the samples.

Cook, Russell, and Assistant Scientist Joel Harringa, MSMSE’92, have applied for a patent. Working with Theron Lewis, MSE 4, they plan a more extensive study of the material’s preparation and properties.