Groundwater Quality and Laundromat Wastewater: Summit Lake, Wisconsin

Abstract: Rural laundromats in northern Wisconsin are, many times, limited to on-site land disposal of their laundry wastewater. The potential for contamination of groundwater by the application of untreated laundry wastewater has been largely unknown. In this investigation, groundwater quality was determined at a laundromat site that utilizes a disposal (seepage) pond. Through discharge to this pond for almost 25 years, the unintentional result was the establishment of a unique wetland system in which natural processes have been effective in assimilating the organic fraction of laundry wastewater. Elevated concentrations of inorganic parameters in a monitoring well close to the disposal pond confirm the migration and potential impacts of inorganic solutes. More distant monitoring wells showed no elevated inorganic concentrations based on horizontal groundwater movement. Vertical migration of the contaminants was not studied and is unknown. The organic fraction of laundry wastewater was biologically degraded indicating some level of biological treatment is desirable. In rural settings, constructed wetlands may offer a cost-effective disposal option provided on-site disposal is the only alternative. Tolerance for elevated groundwater concentrations of inorganic solutes is predicated on pertinent groundwater quality standards.