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Distribution System Contamination Prevention: Mechanisms and Solutions

Mechanisms

Hypothesized Necessary Conditions

Proposed Best Practices

Household Storage: A household’s water storage supply can be contaminated if hands, debris, animals or improperly washed utensils are dipped into the storage tank

  • Lack of faucets
  • Open tank
  • Sealed tank with   adequate household plumbing

Cross Contamination: Negative pressure transients in pipes or privately attached pumps can suck contaminated water from household storage systems or other connections into the distribution system.

  • Intermittent supply
  • Submerged outlets
  • Connection to contaminated source (ground water, contaminated storage water…)
  • Negative internal pipeline pressure
  • Float valve in water tanks
  • Backflow prevention device
  • Prohibition against private pumps
  • Proper operator training

Pipeline intrusion:  May occur when there is a leak or other type of pathway and the internal pressure of the pipeline drops below external hydrostatic pressure, sucking contaminants into the system.

  • Booster pumps attached to system
  • Large pressure transients (Pump shutdown, sudden valve closure…)
  • High water table
  • Contaminated soil profile
  • Elevated storage tanks
  • Prohibition against private pumps
  • Proper operator training
  • First flush system in household distribution tanks
  • Check valves at household outlets

Bacterial Growth inside the pipeline: Potentially may occur if there was a constant, stagnant volume of water kept inside a pipeline for extended periods of time  (unlikely)

  • Constant water level
  • Stagnant water
  • Regularly use distribution system
  • Usually, a little excess chlorine is dosed to prevent growth in the distribution lines
Section
Column
Members

Alicia Peters
David Gold
Weier Chen
Lucia Garcia-Iturri Gallego  

Email Team

See also:

Village Supply Team

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Documents

 

Challenges

Tasks

Symposium

Final Presentation

Final Report

Fall '14 

 

     
Section
Column
See also:

Village Supply Team

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Members

Alicia Peters
David Gold
Weier Chen
Lucia Garcia-Iturri Gallego  

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