Wallace Water Treatment Plant

Wallace, Idaho

PROJECT OVERVIEW

The Safe Drinking Water Act required East Shoshone County Water District to filter their four surface water intakes that serve Wallace, and Mullan, ID.  Due to the location of the small site next to Placer Creek & limited land availability, a slow sand filter was not a cost effective solution.  Welch Comer completed a study of alternative filtration technologies for the District which analyzed three different types of filtration; rapid sand, cartridge and membrane filtration. 

Although not the least cost option, the District elected to pursue membrane filtration due to its ability to comply with the expected requirements of the Enhanced Surface Water Treatment Rule.

Welch Comer first designed and bid a comprehensive competitive pilot filter study for membrane filter manufacturers that required both capital and operational costs to be considered in the bid.  After the membrane filter manufacturer was selected, Welch Comer designed the water treatment plant around the specific equipment.  Welch Comer also designed upgrades to the District's existing facilities to facilitate the WTP operation.  Welch Comer provided continuous construction phase services for the projects.

KEY ELEMENTS

  • Site Raised Approximately 12 feet to Place the Building Above the 100-year Flood Plain
  • Wallace Water System Remained in Continuous Use While the Filter Plant was Constructed
  • Avoided Costly Stream Crossing Permits and Construction by Converting Existing Stream Crossing Waterlines to Backwash Lines to Infiltration Pond
  • Utilizes an IDEQ Permitted Rapid Infiltration Pond to Dispose of WTP  Backwash, which avoided NPDES Permitting
  • Procured Permits from IDEQ & Shoshone County
  • Completed Land Acquisition with Adjacent Property Owner

 

Wallace water treatment plant building in narrow Placer Creek Canyon.

 

Microfiltration water treatment trains.