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DENVER ZOO Lion’s Quarters Recycle Cross-connection

DENVER ZOO Lion’s Quarters Recycle Cross-connection. Fred J. Sanchez Denver Water, Water Quality Investigations Supervisor. AGENDA. CROSS-CONN @ THE DENVER ZOO RECYCLE SYSTEM OVERVIEW BACKGROUND INFORMATION INCIDENT DESCRIPTION ACTIONS TAKEN INVESTIGATION RESULTS CORRECTIVE MEASURES.

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DENVER ZOO Lion’s Quarters Recycle Cross-connection

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  1. DENVER ZOOLion’s QuartersRecycle Cross-connection Fred J. Sanchez Denver Water, Water Quality Investigations Supervisor

  2. AGENDA • CROSS-CONN @ THE DENVER ZOO • RECYCLE SYSTEM OVERVIEW • BACKGROUND INFORMATION • INCIDENT DESCRIPTION • ACTIONS TAKEN • INVESTIGATION RESULTS • CORRECTIVE MEASURES

  3. Acknowledgments • Water Quality Personnel • WQ Investigations • Cross-connections • Water Control Personnel • Emergency Services • System Quality • Denver Zoo Personnel • VP for Planning • Zoo Staff • My personal friend…

  4. DENVER WATER’S RECYCLE SYSTEM • Metro Wastewater Reclamation provides Denver Water’s Recycle Plant with source water • The source is further treated by Denver Water • Biological Nitrification • Chemical Coagulation • Flocculation • Granular Media Filtration • Chlorine Disinfection • DW provides both potable & recycled water to the Denver Zoo

  5. DENVER ZOO’S RECYCLE SYSTEM • Takes recycled water from Denver Water’s Recycling Distribution System • Supplied by the Zoo’s Pump Station • Owned & Operated by the Zoo • Primary use… • Wash Down purposes in the animal pens

  6. DENVERWATER’S RECYCLE SYSTEM PHASE I MAP METROWASTE WATER DWRECYCLEPLANT DENVERZOO

  7. LNQ’S BACKGROUND INFORMATION • Both Potable & Recycle lines are located in the LNQ’S Mechanical Room • The potable & recycle water entering the mechanical room have separate services • Potable is used for animal food prep, employee wash room, and hose bibs. • Recycle is primarily used for wash down purposes in the Lion’s holding quarters since May 2005.

  8. LNQ’S RECYCLE & POTABLE SYSTEM RECYCLE LINE LION’S WASH-DOWN LINE PHYSICAL SEPARATION POTABLE SERVICE WATER

  9. INCIDENT DESRIPTION • February 27, 2006 • DW scheduled a meeting with Zoo staff • Discuss a means of temporarily supplying the Zoo’s recycle system with potable water • Accommodate recycle system construction • Conceptual Plan • Physically disconnect the ‘recycled source’ at LNQ • 2-Inch Diameter Pipe • Cut & Cap • Connect the ‘potable line’ as the new source protected by a Reduced Pressured Zoned Backflow Prevention Device (RPZ)

  10. INCIDENT... • During the meeting on Feb 27th • DW discovered the conversion was done incorrectly • A direct “Cross-connection” between the potable & recycled water lines was created • The Zoo’s pump station was operating during the discovery

  11. CROSS-CONNECTION RECYCLE LINE CROSS-CONNECTION POTABLE SERVICE WATER

  12. ACTIONS TAKEN • Denver Water Personnel & Zoo Personnel surveyed the potable system for contaminated drinking water (Recycle) • Used Specific Conductance Meters (µS) • Potable Source = 300 µS • Recycle Source = 700 – 900 µS

  13. ACTIONS… • Utilized Zoo’s Engineering Drawings & Tested Conductivity • Fire Hydrants • Water Fountains • Sink Taps • Potable Water Service Lines • DW’s Distribution System • Outside Zoo’s property

  14. ACTIONS… • Collected bacteriological samples • Drinking Fountains • Break Room Taps • Food Vendors • Pending the bacteriological results • DW recommended isolating the Zoo’s system • Prevent public contact with the drinking water until further notice • No Human Consumption

  15. INVESTIGATION RESULTS • The conductivity results showed • Small portion of the Zoo’s potable system was contaminated with Recycle water • LNQ’s Domestic Service Line • 3-inch diameter x 345-ft • Zoo’s Distribution Main • Service to the LNQ bldg. • 8-inch diameter x 30-ft

  16. Zoo's POTABLE DISTRIBUTION SYSTEM CONTAMINATED SERVICE

  17. CONTAMINATED SERVICE LINE & WATER MAIN

  18. CORRECTIVE MEASURES • Remove the Cross-connection between the Potable & Recycle Line • Physically separate the two systems

  19. APPROVED PHYSICAL SEPARATION RECYCLE LINE APPROVED SEPARATION POTABLE SERVICE WATER

  20. CORRECTIVE MEASURES… • Flush, Disinfect, Test Contaminated Service Lines & Distribution Water Main • Ozonation Method = 1.0 mg/L Dosage • Kills Pathogenic Organisms • Kills Cryptosporidium • Collected Bacteriological Samples • Service Lines • Distribution System Fire Hydrant

  21. CORRECTIVE MEASURES… • Ensure the Zoo complies with Recycle Water Regulations • Backflow Prevention • Marking & Signage • Create a Management of Change Protocol • Ensure Zoo staff & contractors have approval for future modifications • Provide additional training to Zoo staff • Regulations Requirements • Protect the public water system from contamination

  22. CONCLUSION • The Cross-connection was removed • All bacteriological results from the initial water quality survey were negative • All bacteriological results from disinfection process were negative • The Zoo has “High Quality H20” • Most Important…

  23. MOST IMPORTANT KEEP FRED’S FRIENDS LOCKED UP “AT ALL TIMES”!

  24. Q&A ?

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