Wasilla council hears plan to use adjacent wetlands for treated effluent and to upgrade sludge handling

Wasilla City Council members on May 19 heard from Stantec Consulting about a two-part plan to relieve capacity limits and reduce groundwater impacts at the Wasilla Wastewater Treatment Plant.

Dean Sido, a Stantec consultant, told the council the plant is “presently permitted for approximately 400,000 gallons per day” and is “pushing up against that permit limit,” and proposed a wetlands discharge system and related upgrades that Stantec says could increase permitted disposal to 500,000 gallons per day.

The discussion matters locally because the plant’s existing percolation beds have largely failed and excess effluent is reaching groundwater. “So right now, the effluent that is applied into the beds, is essentially being directed to the groundwater below the water plant, which is putting some of the nitrate and ammonia constituents into the groundwater,” Sido said during his presentation.

Nut Graf — why this matters: City staff and the consultants said the proposal aims to buy time and reduce environmental risk by routing treated effluent through vegetated wetlands that can “consume the nitrates, the ammonia, the various nutrients from the wastewater,” according to the presentation. The plan also includes separate work to expand sludge digestion, add mechanical dewatering and modernize operations to reduce odors and cut reliance on the existing drying beds.

Key points and timeline

- Permit and approvals: Stantec has applied for a U.S. Army Corps of Engineers Section 404 permit (wetlands permit) and reported the application is in legal review. Sido said, “We are probably 1 or 2 months away from achieving that permit.” Once the Corps permit is issued, the city would acquire easements or property, seek Alaska Department of Environmental Conservation (DEC) approval to construct, then apply for a state discharge permit.

- Capacity: The wetlands discharge facility is intended to support 500,000 gpd — 100,000 gallons more than the current permit —…