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NYC Filtration Plant for Delaware and Catskill Systems
NYC Filtration Plant for Delaware and Catskill Systems
Filtration avoidance criteria Alternatives to Filtration? Where should the plant(s) be located?
Multiple plants or one plant? Treatment steps at different locations?
Design flow Treatment scheme Backwash water
Filtration avoidance criteria Alternatives to Filtration? Where should the plant(s) be located?
Multiple plants or one plant? Treatment steps at different locations?
Design flow Treatment scheme Backwash water
SDWA Turbidity LoopholeSDWA Turbidity Loophole
At no time can turbidity go above 5 nephelolometric turbidity units (NTU)
Systems that filter must ensure that the turbidity go no higher than 1 NTU (0.5 NTU for conventional or direct filtration) in at least 95% of the daily samples for any two consecutive months
Delaware-Catskill turbidity range was ________ with an average of 1.06 NTU in 2000
NYC claims the MCL of 5 NTU is for a monthly average
At no time can turbidity go above 5 nephelolometric turbidity units (NTU)
Systems that filter must ensure that the turbidity go no higher than 1 NTU (0.5 NTU for conventional or direct filtration) in at least 95% of the daily samples for any two consecutive months
Delaware-Catskill turbidity range was ________ with an average of 1.06 NTU in 2000
NYC claims the MCL of 5 NTU is for a monthly average
0.5-10.0
§ 141.71 Criteria for avoiding filtration.
§ 141.71 Criteria for avoiding filtration.
The turbidity level cannot exceed 5 NTU (measured as specified in § 141.74 (a)(4) and (b)(2)) in representative samples of the source water immediately prior to the first or only point of disinfectant application unless: (i) the State determines that any such event was caused by circumstances that were unusual and unpredictable; and (ii) as a result of any such event, there have not been more than two events in the past 12 months the system served water to the public, or more than five events in the past 120 months the system served water to the public, in which the turbidity level exceeded 5 NTU. An ‘‘event’’ is a series of consecutive days during which at least one turbidity measurement each day exceeds 5 NTU.
The turbidity level cannot exceed 5 NTU (measured as specified in § 141.74 (a)(4) and (b)(2)) in representative samples of the source water immediately prior to the first or only point of disinfectant application unless: (i) the State determines that any such event was caused by circumstances that were unusual and unpredictable; and (ii) as a result of any such event, there have not been more than two events in the past 12 months the system served water to the public, or more than five events in the past 120 months the system served water to the public, in which the turbidity level exceeded 5 NTU. An ‘‘event’’ is a series of consecutive days during which at least one turbidity measurement each day exceeds 5 NTU.
Limited Alternative To FiltrationLimited Alternative To Filtration
States may allow unfiltered water systems with surface water sources to use treatment other than filtration
In order to qualify for alternative treatment, a water system must have an __________, ____________ watershed in consolidated ownership and have control over access to and activities in the watershed
The alternative treatment must ensure _________ removal or inactivation efficiencies of pathogenic organisms than would be achieved by the combination of filtration and chlorine disinfection required by section 1412 (b)(7)(C). [1412(b)(7)(C)] Sec. 106
States may allow unfiltered water systems with surface water sources to use treatment other than filtration
In order to qualify for alternative treatment, a water system must have an __________, ____________ watershed in consolidated ownership and have control over access to and activities in the watershed
The alternative treatment must ensure _________ removal or inactivation efficiencies of pathogenic organisms than would be achieved by the combination of filtration and chlorine disinfection required by section 1412 (b)(7)(C). [1412(b)(7)(C)] Sec. 106
uninhabited undeveloped
greater
§ 141.71 Criteria for avoiding filtration
§ 141.71 Criteria for avoiding filtration
The public water system must demonstrate through ownership and/or written agreements with landowners within the watershed that it can control all human activities which may have an adverse impact on the micro-biological quality of the source water. The public water system must submit an annual report to the State that identifies any special concerns about the watershed and how they are being handled; describes activities in the watershed that affect water quality; and projects what adverse activities are expected to occur in the future and describes how the public water system expects to address them.
The public water system must demonstrate through ownership and/or written agreements with landowners within the watershed that it can control all human activities which may have an adverse impact on the micro-biological quality of the source water. The public water system must submit an annual report to the State that identifies any special concerns about the watershed and how they are being handled; describes activities in the watershed that affect water quality; and projects what adverse activities are expected to occur in the future and describes how the public water system expects to address them.
Where Should Plant(s) Be Located?
Where Should Plant(s) Be Located?
______________________________________________________________________
___________________________________ ___________________________________ ___________________________________
______________________________________________________________________
___________________________________ ___________________________________ ___________________________________
Between last watershed reservoir (Kensico) anddistribution reservoir (Hillview)
Near tunnel
On hydraulic grade line! (No pumps)
Commercial/Industrial area (not residential)
Design Flow for New Filtration Plant
Design Flow for New Filtration Plant
Max day ever was 94 m3/s in 1975 Future growth? Conservation?
Croton system is separate Proposed filtration plant for 12.7 m3/s Ability to shut down Croton system?
Catskill/Delaware plant Expert Panel 48.3 m3/s NYCDEP (Debra Thomas 10/27/97) 83 m3/s
Max day ever was 94 m3/s in 1975 Future growth? Conservation?
Croton system is separate Proposed filtration plant for 12.7 m3/s Ability to shut down Croton system?
Catskill/Delaware plant Expert Panel 48.3 m3/s NYCDEP (Debra Thomas 10/27/97) 83 m3/s
Croton PlantCroton Plant
The construction costs of the water filtration plant, with a design capacity of 290 million gallons per day (mgd), and the related facilities, is estimated at $660 million.
Annual operations and maintenance costs are projected to be $11 million.
The plant will use state-of-the-art disinfection and filtration processes including dissolved air flotation for the removal of solids, ozonation for primary disinfection, and biologically active carbon filtration.
The construction costs of the water filtration plant, with a design capacity of 290 million gallons per day (mgd), and the related facilities, is estimated at $660 million.
Annual operations and maintenance costs are projected to be $11 million.
The plant will use state-of-the-art disinfection and filtration processes including dissolved air flotation for the removal of solids, ozonation for primary disinfection, and biologically active carbon filtration.
3 3
33
$660,000,000 $5212.7
$5283 4.3 !
millionm s m s
millionm s billion
m s
=
× =
Maximum Daily FlowMaximum Daily Flow
0.00.010.010.020.020.030.030.040.040.050.050.060.060.070.070.080.080.090.090.0
1978
1978
1980
1980
1982
1982
1984
1984
1986
1986
1988
1988
1990
1990
1992
1992
1994
1994
yearyear
Max
imum
dai
ly d
eman
d (m
3 /s)
Max
imum
dai
ly d
eman
d (m
3 /s)
Catskill/DelawareCatskill/Delaware
CrotonCroton
Treatment Plant Options for NYC
Treatment Plant Options for NYC
NYC’s water is high quality (<2 NTU) Low particle concentration means that
___________ ______ aren’t necessary Three options for WTP with high quality
surface waters Direct Filtration (most likely option for NYC) Contact Filtration Ultraviolet disinfection
NYC’s water is high quality (<2 NTU) Low particle concentration means that
___________ ______ aren’t necessary Three options for WTP with high quality
surface waters Direct Filtration (most likely option for NYC) Contact Filtration Ultraviolet disinfection
sedimentation basins
Direct FiltrationDirect Filtration
ScreeningScreening
Rapid MixRapid Mix
FlocculationFlocculation
FiltrationFiltration
DisinfectionDisinfection
StorageStorage
DistributionDistribution
Raw waterRaw water
AlumPolymers
AlumPolymers Cl2Cl2
sludgesludge sludgesludge
Contact FiltrationContact Filtration
ScreeningScreening
Rapid MixRapid Mix
FiltrationFiltration
DisinfectionDisinfection
StorageStorage
DistributionDistribution
Raw waterRaw water
AlumPolymers
AlumPolymers Cl2Cl2
sludgesludge sludgesludge
Size of Major Unit ProcessesSize of Major Unit Processes
Unit Process Parameter Range
Flocculation 10-30 min
Sedimentation Q/As 0.67 m/hr
Filtration Va 2.5 - 37 m/hr
Los Angeles - _______
NYC considering 15 - 30 m/hr (likely 25 m/hr)
Unit Process Parameter Range
Flocculation 10-30 min
Sedimentation Q/As 0.67 m/hr
Filtration Va 2.5 - 37 m/hr
Los Angeles - _______
NYC considering 15 - 30 m/hr (likely 25 m/hr)
37 m/hr
Backwash RequirementsBackwash Requirements
U FB B
TTotal filter bed areaotal filter bed area
Useable production (or area)
Production used for backwash
Filter beds off line to be backwashed
AT = AU + AFB + AB
Area of Filter Beds in Useable Production (U)
Area of Filter Beds in Useable Production (U)
Plant Design Flow 83 m3/s
Area required without backwash (Va = 25 m/hr)
Backwash requirements? 10 minutes at 50 m/hr once every 12 hours assume 30 minute downtime for backwash The useable filter bed area must be increased by 5 – 10%
to meet backwash requirements
Plant Design Flow 83 m3/s
Area required without backwash (Va = 25 m/hr)
Backwash requirements? 10 minutes at 50 m/hr once every 12 hours assume 30 minute downtime for backwash The useable filter bed area must be increased by 5 – 10%
to meet backwash requirements
23
U m 11,952
s 3600hr
hrm 25
/sm 83
VQ
A 23
U m 11,952
s 3600hr
hrm 25
/sm 83
VQ
A 36.4 ha siteha=10,000 m2
Backwash Water Disposal Options
Backwash Water Disposal Options
Backwash water production Approximately 3% of useable production! Not recycled because of potential concentration
of pathogens Solids production
particles present in raw water (0.1-10 mg/L) coagulant (5 - 50 mg/L)
Disposal options
Backwash water production Approximately 3% of useable production! Not recycled because of potential concentration
of pathogens Solids production
particles present in raw water (0.1-10 mg/L) coagulant (5 - 50 mg/L)
Disposal options
Area of Flocculation TanksArea of Flocculation Tanks
Hydraulic retention time of 10-30 minutes Los Angeles uses 8 minutes
Typical depth of 5 meters Area required for flocculation will be
similar to that required for filtration Contact filtration would eliminate the need
for flocculation tanks
Hydraulic retention time of 10-30 minutes Los Angeles uses 8 minutes
Typical depth of 5 meters Area required for flocculation will be
similar to that required for filtration Contact filtration would eliminate the need
for flocculation tanks
SummarySummary
NYC Catskill/Delaware WTP (if built) will be either direct or contact filtration
The WTP will be constructed somewhere between Kensico and Hillview Reservoirs
The WTP will be designed to handle recent peak daily flows: future demand will need to be restricted to current levels
The WTP will cost several billion dollars In the meantime, NYC will build an ultraviolet
disinfection plant.
NYC Catskill/Delaware WTP (if built) will be either direct or contact filtration
The WTP will be constructed somewhere between Kensico and Hillview Reservoirs
The WTP will be designed to handle recent peak daily flows: future demand will need to be restricted to current levels
The WTP will cost several billion dollars In the meantime, NYC will build an ultraviolet
disinfection plant.
Supply Aqueducts and Tunnels
Catskill Aqueduct
Delaware Aqueduct
East Delaware tunnel
West Delaware tunnel
Shandaken Tunnel
Neversink Tunnel
Kensico to Hillview
Kensico to Hillview
CatskillAqueductCatskillAqueduct
DelawareAqueductDelawareAqueduct
Possible Filtration Plant SitePossible Filtration Plant Site
Kensico
1 km
90 acre site36.4 haha=10,000 m2
Close to Catskill and Delaware Aqueducts
Possible Filtration Plant SitePossible Filtration Plant Site