This past November (2015) Clean Fuel Partners begin installation of a Cupola M2 two membrane gasholder dome (Ecomembrane ™) on digester #2 at the Dane County digester facility. Crew members Eric Schumann, Brandon Schroeder, Alex Jaeger & Mike Maras are shown in the photogallery (see below) during the installation process. Photos by engineer Ben Sheff.

The “duel membrane” system has four major components to it: tension straps, netting and two individual polypropylene covers. All layers are anchored to the crown on top of the tank.

Tension straps and a net support are installed first to support the roof system during the installation as well as throughout the operation of the digester. This support system protects the roof membranes from being damaged by the digester mixers or other potential hazards in the slurry inside the tank.

The taut outer membrane, inflated by an air pump, acts as a protective barrier from the elements while the inner membrane remains flexible to adjust to the methane production changes.