Hydrogeology > Project Case Study

Send by emailPrint page

Hydrogeologic and DBP Reduction Study

Wright-Pierce was selected to develop alternatives to bring the District’s existing slow sand treatment process into compliance with the Stage 1 Disinfection By-Products rule.  A comprehensive study investigated several alternatives for both improved water treatment processes and new groundwater development.

An extensive disinfection study reviewed the District’s procedures and investigated alternatives, including ultraviolet light in conjunction with chloramination, and free chlorine for viral deactivation. Simulation testing, performed by Wright-Pierce lab technicians, revealed successful reduction of disinfection by-product formation. Procedure modifications were proposed enabling District compliance with Safe Water Drinking Act (SWDA) standards.  

Published geologic data and previous consultant studies indicated favorable groundwater aquifers did not exist within the distribution system.  Wright-Pierce conducted a surficial geology mapping study and test well exploration program resulting in the development of a high quality, 200 GPM,  gravel-pack, well supply adjacent to Eagle Lake. 

Two,  200 GPM wells and a pump station have been permitted and constructed. The existing slow sand treatment process will be abandoned and replaced with a new groundwater source.

Back To > Hydrogeology Services
Project Highlights

Background

Wright-Pierce conducted a comprehensive study of both treatment and source alternatives to bring the District into compliance with Stage 1 D/DBP EPA rules.

Challenges

  • District D/DBP issues threaten non-compliance with SWDA Standards
  • Inadequate existing slow sand filtration system resulting in unacceptable disinfection  by-product levels
  • Limited groundwater resources

Solutions

  • Innovative hydrogeologic testing located new ground-water source for blending or as replacement
  • Slow sand facility to be placed in inactive stage