1 DENVER ZOO Lion’s Quarters Recycle Cross-connection Fred J. SanchezDenver Water, Water Quality Investigations Supervisor
2 AGENDA CROSS-CONN @ THE DENVER ZOO RECYCLE SYSTEM OVERVIEW BACKGROUND INFORMATIONINCIDENT DESCRIPTIONACTIONS TAKENINVESTIGATION RESULTSCORRECTIVE MEASURES
3 Acknowledgments My personal friend… Water Quality Personnel WQ InvestigationsCross-connectionsWater Control PersonnelEmergency ServicesSystem QualityDenver Zoo PersonnelVP for PlanningZoo StaffMy personal friend…
5 DENVER WATER’S RECYCLE SYSTEM Metro Wastewater Reclamation provides Denver Water’s Recycle Plant with source waterThe source is further treated by Denver WaterBiological NitrificationChemical CoagulationFlocculationGranular Media FiltrationChlorine DisinfectionDW provides both potable & recycled water to the Denver Zoo
6 DENVER ZOO’S RECYCLE SYSTEM Takes recycled water from Denver Water’s Recycling Distribution SystemSupplied by the Zoo’s Pump StationOwned & Operated by the ZooPrimary use…Wash Down purposes in the animal pens
7 DENVER WATER’S RECYCLE SYSTEM PHASE I MAP METRO WASTE WATERDW RECYCLE PLANTDENVER ZOO
8 LNQ’S BACKGROUND INFORMATION Both Potable & Recycle lines are located in the LNQ’S Mechanical RoomThe potable & recycle water entering the mechanical room have separate servicesPotable 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.
9 LNQ’S RECYCLE & POTABLE SYSTEM RECYCLE LINELION’S WASH-DOWN LINEPHYSICAL SEPARATIONPOTABLE SERVICE WATER
10 INCIDENT DESRIPTION February 27, 2006 Conceptual Plan DW scheduled a meeting with Zoo staffDiscuss a means of temporarily supplying the Zoo’s recycle system with potable waterAccommodate recycle system constructionConceptual PlanPhysically disconnect the ‘recycled source’ at LNQ2-Inch Diameter PipeCut & CapConnect the ‘potable line’ as the new source protected by a Reduced Pressured Zoned Backflow Prevention Device (RPZ)
11 INCIDENT... During the meeting on Feb 27th DW discovered the conversion was done incorrectlyA direct “Cross-connection” between the potable & recycled water lines was createdThe Zoo’s pump station was operating during the discovery
12 CROSS-CONNECTIONRECYCLE LINECROSS-CONNECTIONPOTABLE SERVICE WATER
13 ACTIONS TAKENDenver Water Personnel & Zoo Personnel surveyed the potable system for contaminated drinking water (Recycle)Used Specific Conductance Meters (µS)Potable Source = 300 µSRecycle Source = 700 – 900 µS
14 ACTIONS… Utilized Zoo’s Engineering Drawings & Tested Conductivity Fire HydrantsWater FountainsSink TapsPotable Water Service LinesDW’s Distribution SystemOutside Zoo’s property
15 ACTIONS… Collected bacteriological samples Drinking FountainsBreak Room TapsFood VendorsPending the bacteriological resultsDW recommended isolating the Zoo’s systemPrevent public contact with the drinking water until further noticeNo Human Consumption
16 INVESTIGATION RESULTS The conductivity results showedSmall portion of the Zoo’s potable system was contaminated with Recycle waterLNQ’s Domestic Service Line3-inch diameter x 345-ftZoo’s Distribution MainService to the LNQ bldg.8-inch diameter x 30-ft
17 Zoo's POTABLE DISTRIBUTION SYSTEM CONTAMINATED SERVICE
19 CORRECTIVE MEASURESRemove the Cross-connection between the Potable & Recycle LinePhysically separate the two systems
20 APPROVED PHYSICAL SEPARATION RECYCLE LINEAPPROVED SEPARATIONPOTABLE SERVICE WATER
21 CORRECTIVE MEASURES…Flush, Disinfect, Test Contaminated Service Lines & Distribution Water MainOzonation Method = 1.0 mg/L DosageKills Pathogenic OrganismsKills CryptosporidiumCollected Bacteriological SamplesService LinesDistribution System Fire Hydrant
22 CORRECTIVE MEASURES…Ensure the Zoo complies with Recycle Water RegulationsBackflow PreventionMarking & SignageCreate a Management of Change ProtocolEnsure Zoo staff & contractors have approval for future modificationsProvide additional training to Zoo staffRegulations RequirementsProtect the public water system from contamination
23 CONCLUSION Most Important… The Cross-connection was removed All bacteriological results from the initial water quality survey were negativeAll bacteriological results from disinfection process were negativeThe Zoo has “High Quality H20”Most Important…
24 KEEP FRED’S FRIENDS LOCKED UP MOST IMPORTANTKEEP FRED’S FRIENDS LOCKED UP“AT ALL TIMES”!
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