Wastewater Treatment Plant Screening and Digester Mixing Upgrade

The St. Johnsbury Wastewater Treatment Plant Screening and Digester Mixing Upgrade project was completed in order to bring much-needed improvements to the existing Treatment Facility. Alongside the Town of St. Johnsbury, Dufresne Group assessed the quality of the existing Treatment Facility screening and digester mixing in order to develop a project that addressed the most necessary components.

Work done for this project includes:

• Construction of a screen room with grinding and cylindrical screen equipment on top of the existing headworks

• Replacing the existing digester boiler

• Renovation of the two existing digesters

• Replacement of digester gas mixers with mechanical mixers

Funded by USDA Rural Development, the project ended up being under budget. As a result, additional improvements were able to be made. These improvements include:

• Miscellaneous alarm upgrades

• Addition of foundation insulation for the primary digester

• Addition of an influent flow meter

• Installation of new roofing for the digester building

• A bridge crane system in the screen room for the screen and grinder maintenance and removal

• Replacement of the gas safety equipment