Moorefield & Bennington Constructed Wetlands Treatment System
Switzerland County was searching for a way to provide wastewater services to two very small communities, Moorefield and Bennington. Estimates showed that tying the roughly 60 homes into a small, traditional wastewater plant would create sewer rates between $90 and $125 per month.
Lochmueller Group (Lochgroup) provided the county with another option: using a constructed wetland for wastewater collection, treatment, and disposal. Lochgroup prepared a preliminary engineering report and final designs for two separate systems – one in Moorefield and one in Bennington.
First, homes were outfitted with systems similar to traditional septic systems. Unlike a traditional system though, each home has a two-compartment tank. Waste from the home flows through the tank, then a small but powerful pump carries wastewater to a unified treatment system. These small pumps can move wastewater several miles to the final treatment destination.
For each of the communities, this system includes a two-celled gravel and plant treatment system that is approximate 40 feet by 40 feet. The cells are built with an anaerobic layer at the bottom, a separating liner, then an aerobic layer on top. The aerobic layer consists of gravel and specifically-selected plants whose roots absorb nitrogen from the wastewater.
A pump recirculates the water in the wetland with a portion of the treated water diverted and pumped into an approximately 1.5-acre drip field where it’s emitted through small subsurface tubes. These fields are planted in hay through a no-till method. The treated wastewater acts as an irrigation system and the community is able to harvest and sell the hay.
This system’s low construction and maintenance cost meant the 60 homes connected to the system pay $30 per month in sewer fees. Both communities have the ability to expand the system if needed.