Since 2014, MD&E has been conducting design-building-operate services for closure of an alum tailings impoundment in central Wisconsin. Services have included collecting and evaluating environmental impact data (leachate, soil, and groundwater), design, construction, and operation of an industrial wastewater (alum supernatant) treatment facility, and design and construction management for installation of the final cover system for the empty impoundment. Wastewater treatment has included gypsum and ettringite precipitation/sedimentation and effluent carbonation. The closure cover system includes an LLDPE flexible membrane and remotely operated leachate collection and management infrastructure.