Gypsum wallboard (drywall), commonly used to cover the interior walls of buildings, represents 20 percent of the waste generated during the construction of new commercial and residential sites in Wisconsin. Until recently, much of this waste was being disposed of in Wisconsin’s landfills. However, a new policy put into effect by the Wisconsin Department of Natural Resources is paving the way for drywall to become a resource instead of a waste, helping the environment and saving builders money.
In October, the state DNR approved a low-hazard grant of exemption that will allow builders and contractors who have completed a simple application process to store, process and land-spread waste gypsum wallboard as a soil amendment.
Gypsum, the primary component of drywall, can be used as an agricultural fertilizer and soil amendment because it is made up of about 20 percent calcium and 15 percent sulfur, both essential plant nutrients. Plants need calcium in order to ensure proper cell division and to maintain normal functioning of cellular membranes. Plants need sulfur in order to produce specific amino acids. Thus, by grinding and land-spreading waste drywall, waste is eliminated from our landfills, those responsible for the disposal of the waste drywall save on disposal costs and a rich fertilizer for agricultural crops is produced.
“The approval of this low-hazard grant exemption by the DNR will greatly impact construction waste recycling in Wisconsin,” said Jenna Kunde, executive director of WasteCap Wisconsin. “Nearly every waste-reduction and recycling project we work on within the construction industry generates waste drywall that needs to be dealt with. The ability to recycle this waste, while also providing valuable agronomic benefits, paves the way for us to significantly reduce this specific waste stream.”
Builders and contractors who wish to use the DNR’s low-hazard exemption for substituting waste gypsum wallboard for agricultural gypsum need only to follow several simple steps.
First, a formal exemption from the local DNR office must be obtained. This can be acquired by submitting a letter requesting the low-hazard exemption and paying the permit fee.
Second, segregate the scrap drywall on site. Only new scrap wallboard that has not been treated with surface chemicals and is relatively free of tape, joint compounds, paint, nails, screws or other contaminants should be used. In addition, all scraps should be stored on site in a manner that minimizes rainwater runoff from the storage area.
Third, grind the drywall. The wallboard should be ground to a size that allows for easy and even distribution on the farm fields sited for spreading and in a way that controls the dust generated by the grinder itself.
Fourth, determine the application rate for land-spreading. The application rate for the ground drywall will be based on the current sulfate content of the field and the sulfur needs of the crop to be planted in the field.
Last, apply the ground drywall to the field in accordance with soil and agronomic nutrient requirements.
Alternatively, builders who contract with WasteCap Wisconsin for construction waste management services can take advantage of the blanket exemption granted to WasteCap by the DNR for its projects.
“We have been working with the DNR for over two years to see this exemption come to fruition, and we are very excited that recycling a large component of Wisconsin’s construction and demolition waste stream just got easier,” said Ralph McCall, project manager for WasteCap Wisconsin.
More information about the low-hazard grant exemption, how to properly manage scrap drywall and the application allowing for the processing of gypsum wallboard can be found on WasteCap Wisconsin’s Web site.
Amber Zuhlke is an outreach specialist with WasteCap Wisconsin.