Dec. 3, 2009

Compost facility

Ag specialist Steve Jonas turns one of the windrowed piles of compost. Temperatures within the piles reach 140-160 degrees. Photo by Bob Elbert.

Environmental aromatherapy

by Erin Rosacker

The white, vinyl-clad hoop structures at Iowa State's new dairy farm aren't protecting equipment, livestock or hay bales. These hoop barns were constructed in 2008 to serve as the university's compost facility, a collaborative campus effort to convert organic waste and expand sustainability efforts.

The recipe

The compost facility accepts materials from several campus departments, blending them into an assortment of usable products. Ingredients include:

  • Manure from the dairy farm
  • Used bedding materials from ISU livestock farms
  • Food waste from ISU Dining
  • ISU greenhouse waste, such as plant materials
  • Biomass, such as cornstalks and leaves
  • Ground-up wood from discarded pallets
  • Topsoil from campus construction projects

Composting essentially speeds up the decomposition of organic materials, producing a rich soil additive. A proper mix of nitrogen (manure) and carbon (such as biomass waste or bedding) will heat up and cook as it sits in windrowed piles. Temperatures within the piles reach 140-160 degrees. The windrows are turned once or twice weekly over the 10 to 12 weeks they are cured in the hoop barns.

The finished -- and remarkably odorless -- products are used several ways. One of the compost mixtures is used for livestock bedding (in place of sawdust), and the windrowed compost is distributed on ag and horticulture field plots. A compost mixture with added topsoil and sand is used in flowerbeds and landscaping, including planted areas around newly constructed campus buildings.


Composting benefits the environment by diverting organic materials from landfills and the water supply. The ISU facility also benefits the bottom line, operating as a self-supported unit. Departments are charged for materials brought into the facility, and campus units and researchers also can purchase the finished compost products -- an economical alternative to commercial sources. The facility is for campus use only, and not open to public drop-offs or purchases.

More than 8,000 tons of manure have been processed since the composting facility opened in December 2008, generating approximately 3,000-4,000 tons of compost.

ISU Dining started sending some of its food waste to the facility this fall, averaging about 36 tons per month when classes are in session. Expect to see that amount increase in the future, when more dining locations start sending food waste to the facility.