Viridi Energy Transforming Digester Facility in Maine into Biosolids-to-RNG Project
Viridi Energy, a renewable natural gas (RNG) platform, has acquired a biosolids digester plant in Brunswick, Maine, and plans to turn the site into a waste-to-RNG facility.
The facility will generate renewable energy to help power the local community, offer a sustainable and cost-effective solution for managing biosolids, and support compliance with local regulations attempting to mitigate per- and poly-fluoroalkyl substance (PFAS) contamination in the region.
Casella Waste Systems, a regional solid waste services company, will manage the feedstock collection and delivery logistics for nearly 85,000 tons of biosolids per year from a network of wastewater treatment plants.
The biosolids will be delivered to the overhauled Brunswick facility, where they will be transformed into enough energy to heat more than 3,000 homes for a year using anaerobic digestion. The facility will also supply electricity directly to Brunswick Landing, a 3,300-acre campus with more than 1.6 million square feet of commercial, industrial, and professional office space.
In addition to meeting the growing demand for RNG, the project will yield several environmental benefits across Maine. Once complete, the facility will offer a solution for managing waste that complies with Maine’s PFAS regulations – allowing Casella to repurpose the materials instead of directly disposing of them.
Viridi’s anaerobic digestion solution is projected to reduce the volume of biosolids by nearly 90% — from 85,000 wet tons to 10,000 tons once the material has been digested and dried. Once processed, Casella will transport this leftover material to the landfill in a form that preserves landfill capacity, lessens the need for stabilization material, and reduces transportation distances.
Viridi is currently conducting siting, permitting, and environmental due diligence at the Brunswick site. Retrofit construction of the facility is expected to be completed by the second half of 2025, with full operations set to commence in 2026.
