Presented By: Fred J. Sánchez Water Quality Operations Supervisor
CDPHE Suspected Salmonella in Alamosa s Drinking Water Supply CDPHE & Denver Water Developed a Strategy: Water Distribution Operations Team Water Quality Monitoring/Testing Team Initial Reservoir Inspections Disinfection Method Flushing & Dechlorination Method Cross-Connection Survey CDPHE Requirements
Water Is Suspected by CDPHE No Common Food Source No source of contamination or initial location of Infection confirmed Confirmed Infant Infections
Salmonella bacteria are rod-shaped, flagellated, Gram stain-negative and are known to cause disease in humans, animals, and birds (especially poultry) worldwide. Salmonellosis is spread to people by ingestion of Salmonella bacteria that contaminate food & water.
Organize A Distribution Team Plan For Chlorinating & Flushing Chlorine Dose Injection Method Distribution Sectors Dechlorination Method CDPHE Samples For Salmonella Meet & Inspect Sites With Local Officials
Develop a strategy
City of Alamosa Denver Water CDPHE Colorado Rural Water Association Aurora Water Pueblo Boulder Nebraska East Cherry Creek Valley
Distribution Operations & CDPHE
Distribution System Craft Tower Ross Tower Weber Reservoir
Population: Under 10,000 Water Source: 6 Wells 1 Active During Winter Months Up to 4 During Summer Months Distribution System: 50 miles Pipe Diameter: 4-16 Pipe Type: CA, CI & PVC Average Water Temp: 75º Deep Confined Aquifer State Requirements: Chlorination Waiver Collect 10 Total Coliform Samples per Month Alternating Between Source & Distribution System Sites
Craft Tower Gallons: 500,000 Type: Elevated Storage Tank (Pedestal Spheroid) Condition: Good Ross Tower Gallons: 200,000 Type: Elevated Storage Tank (Standpipe) Condition: Good Weber Reservoir Gallons: 300,000 Type: Ground-level Service Storage Reservoir Condition: Poor; reservoir has noticeable cracks, etc.
Pittsburg Tank & Tower Inspection
Inspection Revealed: No Major Structural Damage Minor Structural Repair Recommended No Potential Environmental Contamination
Rust on Interior Roof
Bird Fecal Matter on Exterior Roof
Overflow Pipe in Good Condition
Cleanout Hatch Good Condition
Pittsburg Tank & Tower Inspection
Inspection Revealed: No Major Structural Damage Minor Structural Repairs Recommended Possible Environmental Contamination
Roof Manway Replacement
Weld Steel Plates Over Holes
Interior View of Holes
Denver Water & CDPHE Inspection
Structural Damage Potential Environmental Contamination Sand accumulation in Reservoir
E X T E R N A L
Before Repair After Repair Weber Reservoir External Problems
Before Repair After Repair Weber Reservoir External Problems
Before Repair After Repair Weber Reservoir External Problems
I N T E R N A L
Internal Sand Removal
Weber Spray Disinfection 100 mg/l
Weber Reservoir Checklist Reservoir Drained & Cleaned All Holes Patched Spray Disinfected @ 100 mg/l Calcium Hypochlorite 12-hr disinfection contact time Selected as Super Chlorination Source 300,000 gallons at 25 mg/l Craft Tower Ross Tower 50 miles of Distribution System
DISINFECTION METHOD FRED J. SANCHEZ
3 Chlorination Sectors Established: Sector 1 Sector 2 Sector 3
Alamosa Chlorination Process Sector I 25 mg/l Sector II Sector III
FIRE HYDRANT
Fire Hose To Trailer
Fire Hose To Chlorine Injection
Chlorine Injection Point
Weber Well Discharge Pipe
Weber Reservoir Aeration Pipe
Disinfection (Injector) Metering Skid/ Chemical Feeder Borrowed from Alamosa s Treatment Plant
Flushing & Dechlorination
Dechlorination Tank Drip Method
PUBLIC SAFETY & COMMUNITY SUPPORT
3 Letters Are Hand Delivered to the Public Red -Flushing at 25 mg/l (March 25 th -28 th ) Do Not Drink! Do Not Prepare Food Do Not Bathe/Shower Toilet Use Only! Yellow -Flushing at 2mg/L (March 29 th 1 st ) Do Not Drink! Do Not Prepare Food Showering Allowed No Babies or Sr. Citizens Toilet Use Allowed Green -Water Is Safe To Drink (April 11 th ) If CDPHE Requirements Are Met: No Salmonella No Crypto No Giardia Radio & Television Also Issue Alerts!
Emergency Water Supplied: Bottled Water Potable Water Trucks Water Used For: Consumption Showering Allows Chlorination Efforts To Continue Begins With 25 mg/l Dose
CROSS-CONNECTION CONTROL
Over 100 Facilities Surveyed For: Direct Cross-Connections Backflow Prevention Hazards Divided: Extreme Must be fixed immediately! Includes: Mortuaries, Car Washes, Dry Cleaners, Meat Packing Plants High Low Priority For Inclusion into CCC Program Includes: Restaurants, Gas Stations, etc. Eventual Inclusion into CCC Program Includes: Retail Stores, Office Buildings, etc.
Direct Cross-Connection Water Heater
Direct Cross-Connection Ice Maker
Sanitary Sewer Truck Direct Cross-Connection
CDPHE REQUIREMENTS
Take Weber Reservoir Off-line Maintain 2mg/L Chlorine Residual In the DS and in the Reservoirs No Total Coliform & Salmonella Positive Samples Contain All Extreme Hazard Cross-Connections Test For Crypto and Giardia
Distribution System Monitoring Plan Developed 20 DS Sample Sites Input Sites in GIS (CO Rural Water Association) Develop an Ongoing Cross-Connection Control Program Commercial Containment Residential Well Containment
Commercial Containment Basic Program Tracking Installation Notification Annual Testing Surveys Residential Containment Wells Commercial & Residential Isolation Educational Campaign Cross-Connection Control Program