top of page

Water Treatment Plant Upgrade

Saint Johnsbury, Vermont

The painted steel clarifier/filter tanks at the St. Johnsbury Water Treatment Facility were deteriorated beyond the point of repair from corrosion. 


Dufresne Group has completed preliminary engineering, which included evaluation of the existing process against ultrafiltration membranes.  During preliminary engineering, ultrafiltration membranes were identified as the preferred alternative due to their expansion and treatment capabilities.


The need to construct a new treatment building on the same site as the existing building was identified in the preliminary engineering phase due to existing space limitations in the existing treatment plant which would have severely limited future expansion ability to meet treatment requirements and the need to continually provide water meeting safe drinking water standards during construction.


Ultrafiltration membrane equipment pre-selection was made to allow for selected equipment to be piloted and approved by the State of Vermont Drinking Water and Groundwater Protection Division. 


The existing building will be used for garage and shop space for the Water System.  Substructure tankage and existing piping at the existing building provides increased pretreatment contact and flocculation time. 


Construction is expected to be complete in 2025.

Key Features

  • First use of ultrafiltration membranes for drinking water treatment in Vermont.

  • Maximum Day Demand of 2 MGD with one 1 MGD ultrafiltration train offline.

  • Completed pilot study of ultrafiltration technology to evaluate water treatment for disinfection byproduct precursor removal, manganese removal and turbidity reduction.

  • Eight different coagulants along with raw water only were evaluated under different pre-treatment conditions (potassium permanganate and sodium hypochlorite pH adjustment) to determine operational and performance effects and identify final design parameters and sizing.

Chad Whitehead, Town Manager
51 Depot Square, Suite 3
St. Johnsbury, VT 05819
Phone: 802.748.3926

bottom of page