HESCO Proactiview Issue #1 May 2006 – Storage Facilities

Finished water storage facilities are coming under increased scrutiny due to their potential to adversely impact water quality in drinking water distribution systems. These facilities, including above ground and elevated storage tanks, have traditionally been designed chiefly with hydraulic considerations in mind, but can in fact cause significant water quality problems if they are not properly designed, operated, and maintained.

Water quality problems associated with finished water storage facilities can be biological, chemical, and/or physical in nature, and can have both direct and indirect negative consequences upon public health. Specifically, these problems can include:

  • Biological Problems
    • Microbial growth
    • Nitrification
    • Pathogen contamination
  • Chemical Problems
    • Disinfectant decay/low disinfectant residual concentrations
    • Chemical contaminants
    • Disinfection byproduct (DBP) formation
  • Physical Problems
    • Corrosion
    • Stratification
    • Sedimentation
    • Icing

Serious public health impacts directly attributable to poor water quality in storage facilities have been well documented, and include several disease outbreaks and even some deaths amongst more vulnerable water system users.

In addition, the United States Environmental Protection Agency’s (EPA’s) recently promulgated Stage 2 Disinfectants and Disinfection Byproduct Rule (Stage 2 DBP Rule) places an increased emphasis on DBP monitoring and compliance. The Stage 2 DBP Rule requires water system operators to first identify locations within their distribution systems with high DBP concentrations, and then designate these locations as compliance monitoring sites. Water storage facilities, when improperly designed or managed, can be sources of high DBP levels within distribution systems.

All of the above problems are commonly triggered by excessive water age, and are compounded by inadequate mixing and stratification of the water within the storage facility. HESCO can help effectively manage and eliminate these problems through unique, fully-integrated mixing systems specifically designed to address the water quality considerations particular to elevated storage tanks, in addition to the hydraulic operational requirements commonly placed on such facilities. HESCO combines their deep technical expertise with high quality components and controls to create a complete solution specifically engineered to suit your facility and system needs. Typical system components, and their role in water quality protection, are outlined below.

  • Altitude valves from GA Industries: enables better operational control of tank water levels, turnover, and age
  • Tank mixing systems from BIF: induces thorough mixing on both tank fill and draft cycles, preventing stagnation, stratification, and dead zones while incurring minimal head loss
  • Tank coatings from Madison Chemical: prevents corrosion and growth of biological films on tank surfaces
  • Telemetry and controls from Healy Ruff: enables tank monitoring and smart, flexible operation optimizing performance against both water quality and hydraulic considerations.

To learn more about water quality issues in storage facilities and how HESCO can help, contact Kevin Livingston or Glenn Hummel at (586) 978-7200.

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