Moonlight Basin Wastewater Treatment Plant #2

Moonlight Basin is approximately 8 miles from the intersection of US Highway 191 and Highway 64 (Big Sky spur road) in Madison County. It has skiing, golfing, and other outdoor activities as well as lodging, food and beverage, fitness/spa, and retail amenities. Moonlight Basin has an established water and sewer utility, but as a growing area, the owner needed additional wastewater treatment infrastructure.

Moonlight Basin’s focus is to grow and develop in a sustainable way. With more expansion on the horizon and knowing that water-use options and resources are not plentiful in the area, they used information and recommendations from a Morrison-Maierle Preliminary Engineering Report (PER) completed in 2015 to select a three-wastewater-treatment-plant concept in its three service areas. Then, they began implementing the WWTP #2 project to handle upcoming developments.

Historically, wastewater effluent at Moonlight Basin was disposed by subsurface infiltration chambers and seasonal irrigation on forest land. However, as the resort continues to grow, that forest irrigation disposal method is less desirable due to land-use conflicts. Morrison-Maierle, following Montana Department of Environmental Quality’s (DEQ) standards, designed a strategy to treat effluent to Class A-1 reuse standards.

The first wastewater treatment plant in Montana to follow these standards, Moonlight Basin WWTP #2 is now compatible with unrestricted reuse application for the golf course in the near term and will also open up more discharge options such as groundwater injection or surface water as they are approved by Montana’s regulatory agencies.

With innovative design solutions and using its client’s goal for creating a resort using sustainable and environmentally friendly measures, Morrison-Maierle’s design team provided a water-wastewater plan for Moonlight Basin’s future growth as a resort and also set an example for water reuse in Montana.