Transcript Risk Management Plan Metropolitan Water District

Chlorine Disinfection of
Drinking Water
California Unified Program 8th Annual Training Conference
February 8, 2006
Presented by:
Paul G. Beswick
Metropolitan Water District of Southern California
Environmental Support Services
(213) 217-5533
[email protected]
Typical Water Treatment Plant
FLASH MIX
Cl2
Mixes chemicals with raw
water containing fine
particles that will not
readily settle or filter out of
the water.
COAGULATION /
FLOCCULATION
SEDIMENTATION
Gathers together fine light particles
to form larger particles (floc) to aid
the sedimentation and filtration
processes.
Settles out larger
suspended particles.
Cl2
PRECHLORINATION
Kills disease causing organisms and
helps control taste-and-odor causing
substances.
CORROSION
CONTROL NaOH Cl
2
CHLORAMINES
Kills disease causing
organisms. Provides
disinfectant residual for
the distribution system.
NH3 Cl2
Adjusts the pH of the treated
water to inhibit corrosion of
pipelines.
FILTRATION
TO DISTRIBUTION
SYSTEM
CLEARWELL
Provides contact time for
disinfection. Stores water
for high demand.
Filters out remaining
suspended particles
DAF 9-20-00
The Chlorine Disinfection Process
Public Health benefits of chlorination
 Process flow
 Process components

Chlorination Public Health Benefit
A critical role protecting US drinking
water supply from waterborne infectious
diseases for over 90 years
 Cholera, typhoid, dysentery, hepatitis A
virtually eliminated
 In over 98% of disinfection systems
 Germicidal potency, residual disinfection
properties, efficiency, economy

Chlorination Public Health Benefit
All Uses of Chlorine
The Chlorination Process
Chlorine Rail Car Unloading
• 90 Ton rail cars
Chlorine Trailer Unloading
• 17/19 Ton Trailers
Stationary Chlorine Tank
• 25 ton stationary tank
Chlorine Cylinder Storage
• 1 ton cylinders
Chlorine Evaporators
Chlorinators
Ejectors
Treatment Chemical Storage
Chemical
Chlorine
Qty
Capacity
3
90 ton rail cars
Caustic (25%)
8
127,000/ 50,000 gal.
Aqueous Ammonia (19%)
4
13,000/10,000 gal.
Chlorine System Safety
- What we are doing

24 hour monitoring and access control

Detailed operating procedures

Highly trained staff

Leak sensors and alarms

Automatic supply shut-off valves

Chlorine containment and neutralization

On-site emergency response capability +
strong relationship with fire dept responders
Control Room
• Operator on duty 24 hours a day.
• Chlorine alarms are received in the Control
Room.
• Chlorine facilities are visually inspected twice a
shift.
Chlorine Trailer Manway
Remote emergency shut-off capability
•
Highly sensitive chlorine gas detector
•
Multiple Emergency Shut-off
Locations
Controlled from several strategic locations
•
Shut-off is immediate
•
Monel Flex Hose Connection
Durable/flexible connection
•
Inspected/replaced regularly
•
Chlorine Gas Monitoring
•Continuous monitoring, alarms locally and in
Control Room
•Sensors strategically placed throughout plant
•Calibrated regularly
Chlorine leak alarms
•Audio/Visual chlorine gas leak alarms immediate notification to all plant personnel.
Vacuum Operation
• Chlorine piped to points of use throughout
plant under vacuum
• Safest method of transmission
New chlorine containment facilities
Chlorine Cargo Trailers Inside
Containment
Chlorine Storage Bay
Caustic Neutralization System
Two 3.5-Ton Chlorine Scrubbers
Chlorine Rail Car Containment
Chlorine Rail Car Containment
Chlorine Rail Car Scrubbers
Good Relations With Fire Dept.
Responders
LAFD Visits Jensen Plant
LAFD Visits Jensen Plant
Where Is The Real
Chlorine Release
Threat?!
Rural Bexar County, Texas
June 28, 2004
3 dead, 50 hospitalized
Graniteville, South Carolina
January 6, 2005
9 killed, 554 hospitalized, ~5,400 evacuated
Graniteville, South Carolina
January 6, 2005
9 killed, 554 hospitalized, ~5,400 evacuated
Graniteville, South Carolina
January 6, 2005
9 killed, 554 hospitalized, ~5,400 evacuated
Graniteville, South Carolina
January 6, 2005
9 killed, 554 hospitalized, ~5,400 evacuated
Where Is The Real Chlorine
Release Threat?!

Two train wrecks in 6 months
– resulted in significant chlorine releases
– 12 dead
– over 600 taken to hospital
– over 5,000 evacuated.
Chlorine Rail Transportation Issues
Rail freight cost cutting, lack of reinvestment, explosive growth, stretched
resources
 Security

– In transit
– Storage while in transit
Identifying hazmat derailment
 Warning local first responders
 Mobilizing specialist response team
