calarp - examination of chemical processes: drinking water treatment presented by: paul beswick -...
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CalARP - Examination of Chemical CalARP - Examination of Chemical Processes:Processes:
Drinking Water TreatmentDrinking Water Treatment
Presented by:Presented by:Paul Beswick - MWDSC Environmental Support ServicesPaul Beswick - MWDSC Environmental Support Services
(213) 217-5533 [email protected](213) 217-5533 [email protected] Forum Annual Conference - 2/4/03CalCUPA Forum Annual Conference - 2/4/03
PurposePurpose
Present an overview of drinking water treatment processes and chemicals
Highlight role of CalARP Regulated Substance(s) (RS) in water treatment
Identify RS process risks and discuss risk mitigation measures
Joseph Jensen Filtration PlantJoseph Jensen Filtration Plant
Robert A. Skinner Filtration PlantRobert A. Skinner Filtration Plant
TO DISTRIBUTION SYSTEM
Typical Water Treatment Plant
PRE-CHLORINATION
Cl2
Kills disease causing organisms and helps control taste-and-odor causing substances.
DAF 9-20-00
FILTRATIONFilters out remaining suspended particles
CLEARWELLProvides contact time for disinfection. Stores water for high demand.
Cl2
Cl2NH3
CHLORAMINESKills disease causing organisms. Provides disinfectant residual for the distribution system.
SEDIMENTATIONSettles out larger suspended particles.
COAGULATION / FLOCCULATIONGathers together fine light particles to form larger particles (floc) to aid the sedimentation and filtration processes.
FLASH MIXMixes chemicals with raw water containing fine particles that will not readily settle or filter out of the water.
Cl2NaOH
CORROSION CONTROLAdjusts the pH of the treated water to inhibit corrosion of pipelines.
TO DISTRIBUTION SYSTEM
Typical Water Treatment Plant
PRE-CHLORINATION
Cl2
Kills disease causing organisms and helps control taste-and-odor causing substances.
DAF 9-20-00
FILTRATIONFilters out remaining suspended particles
CLEARWELLProvides contact time for disinfection. Stores water for high demand.
Cl2
Cl2NH3
CHLORAMINESKills disease causing organisms. Provides disinfectant residual for the distribution system.
SEDIMENTATIONSettles out larger suspended particles.
COAGULATION / FLOCCULATIONGathers together fine light particles to form larger particles (floc) to aid the sedimentation and filtration processes.
FLASH MIXMixes chemicals with raw water containing fine particles that will not readily settle or filter out of the water.
Cl2NaOH
CORROSION CONTROLAdjusts the pH of the treated water to inhibit corrosion of pipelines.
Coagulation/FlocculationCoagulation/Flocculation
COAGULATIONCOAGULATION– The feeding and rapid mixing of one or more The feeding and rapid mixing of one or more
chemicals coagulants into the water, thereby chemicals coagulants into the water, thereby beginning the formation of particles called beginning the formation of particles called floc.floc.
FLOCCULATIONFLOCCULATION– The gentle mixing of water and coagulants The gentle mixing of water and coagulants
to form larger, heavier, more settleable floc.to form larger, heavier, more settleable floc.
CoagulantsCoagulants
Chemicals that consist of positively Chemicals that consist of positively charged ions that neutralize the charged ions that neutralize the negative charges and promote negative charges and promote coagulation.coagulation.
The most commonly used The most commonly used coagulants in water treatment are:coagulants in water treatment are:
– Aluminum Sulfate (Alum) AlAluminum Sulfate (Alum) Al22(SO(SO44))33
– Ferric Sulfate FeFerric Sulfate Fe22(SO(SO44))33
– Ferric Chloride FeClFerric Chloride FeCl33
Coagulant AidsCoagulant Aids
Added to improve coagulation; to build Added to improve coagulation; to build stronger, more settleable floc; to stronger, more settleable floc; to overcome temperature drops that slow overcome temperature drops that slow coagulation; to reduce the amount of coagulation; to reduce the amount of coagulant needed; and to reduce the coagulant needed; and to reduce the amount of sludge produced.amount of sludge produced.
Common coagulant aids:Common coagulant aids:– Activated SilicaActivated Silica– Weighting Agents (Bentonite clay)Weighting Agents (Bentonite clay)– Polyelectrolytes Polyelectrolytes (polymers)(polymers)
FiltrationFiltration
The major purpose of filtration is to The major purpose of filtration is to remove suspended material (turbidity) remove suspended material (turbidity) from water.from water.
Suspended materials are removed when Suspended materials are removed when water passes through a bed of granular water passes through a bed of granular material known as the filter media.material known as the filter media.
Turbidity removal is important for public Turbidity removal is important for public health; it interferes with disinfection by health; it interferes with disinfection by shielding microorganisms from the shielding microorganisms from the disinfectant.disinfectant.
Rapid Sand Vs High Rate Filter MediaRapid Sand Vs High Rate Filter Media
RAPID SAND DUAL-MEDIA TRI-MEDIA
MediumSand
Gravel
Gravel
Gravel
CoarseCoal
CoarseCoal
Fine SandMedium
Sand
Fine Garnet
The Chlorination ProcessThe Chlorination Process
Public Health benefits of chlorinationPublic Health benefits of chlorination Process flowProcess flow Process componentsProcess components Chlorine safety/risk mitigation measuresChlorine safety/risk mitigation measures
Chlorination Public Health BenefitChlorination Public Health Benefit
A critical role protecting US drinking A critical role protecting US drinking water supply from waterborne infectious water supply from waterborne infectious diseases for over 90 yearsdiseases for over 90 years
Cholera, typhoid, dysentery, hepatitis A Cholera, typhoid, dysentery, hepatitis A virtually eliminatedvirtually eliminated
In over 98% of disinfection systemsIn over 98% of disinfection systems Germicidal potency, residual disinfection Germicidal potency, residual disinfection
properties, efficiency, economyproperties, efficiency, economy
Chlorination Public Health BenefitChlorination Public Health Benefit
The Chlorination ProcessThe Chlorination Process
Chlorine Rail Car UnloadingChlorine Rail Car Unloading
• 90 Ton rail cars
Chlorine Trailer UnloadingChlorine Trailer Unloading
• 17/19 Ton Trailers
Stationary Chlorine TankStationary Chlorine Tank
• 25 ton stationary tank
Chlorine Cylinder StorageChlorine Cylinder Storage
• 1 ton cylinders
Chlorine EvaporatorsChlorine Evaporators
ChlorinatorsChlorinators
EjectorsEjectors
Key Chlorine Safety FeaturesKey Chlorine Safety Features
24 hour monitoring and access control24 hour monitoring and access control
Leak DetectorsLeak Detectors
Automatic shut-off valvesAutomatic shut-off valves
Regular preventive maintenanceRegular preventive maintenance
On-site emergency response capabilityOn-site emergency response capability
� Operator on duty 24 hours a day. Operator on duty 24 hours a day.
� Chlorine alarms are received in the Control Chlorine alarms are received in the Control Room.Room.
� Chlorine facilities are visually inspected Chlorine facilities are visually inspected every four hours.every four hours.
Control RoomControl Room
Chlorine Trailer ManwayChlorine Trailer Manway
�Remote emergency shut-off capabilityRemote emergency shut-off capability
�Highly sensitive chlorine gas detectorHighly sensitive chlorine gas detector
Multiple Emergency Shut-off Multiple Emergency Shut-off LocationsLocations
�Controlled from several strategic locationsControlled from several strategic locations
�Shut-off is immediateShut-off is immediate
Monel Flex Hose ConnectionMonel Flex Hose Connection
�Durable/flexible connectionDurable/flexible connection
�Inspected/replaced regularlyInspected/replaced regularly
Chlorine Gas MonitoringChlorine Gas Monitoring
� Continuous monitoring, alarms locally and in Continuous monitoring, alarms locally and in Control RoomControl Room
� Sensors strategically placed throughout plantSensors strategically placed throughout plant
� Calibrated regularlyCalibrated regularly
Chlorine leak alarmsChlorine leak alarms
� Audio / Visual chlorine gas leak alarms Audio / Visual chlorine gas leak alarms provide immediate notification to all plant provide immediate notification to all plant personnel.personnel.
Vacuum OperationVacuum Operation
� Chlorine piped to points of use throughout Chlorine piped to points of use throughout plant under vacuumplant under vacuum
� Safest method of transmissionSafest method of transmission
On-site Emergency Response On-site Emergency Response CapabilitiesCapabilities
Emergency RespondersEmergency Responders
Chlorine “C” - kitChlorine “C” - kit
C-kit Installed in Trailer ManwayC-kit Installed in Trailer Manway
Emergency RespondersEmergency Responders
THANK YOU!THANK YOU!
Questions?Questions?