nyc filtration plant for delaware and catskill systems l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
NYC Filtration Plant for Delaware and Catskill Systems PowerPoint Presentation
Download Presentation
NYC Filtration Plant for Delaware and Catskill Systems

Loading in 2 Seconds...

play fullscreen
1 / 22

NYC Filtration Plant for Delaware and Catskill Systems - PowerPoint PPT Presentation


  • 209 Views
  • Uploaded on

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.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'NYC Filtration Plant for Delaware and Catskill Systems' - lysa


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
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
sdwa turbidity loophole
SDWA 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

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.
limited alternative to filtration
Limited 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

undeveloped

uninhabited

greater

141 71 criteria for avoiding filtration5
§ 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.
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
croton plant
Croton 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.
maximum daily flow
Maximum Daily Flow

90.0

80.0

70.0

60.0

50.0

Maximum daily demand (m3/s)

Catskill/Delaware

40.0

30.0

Croton

20.0

10.0

0.0

1978

1980

1982

1984

1986

1988

1990

1992

1994

year

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

sedimentation basins

direct filtration
Direct Filtration

Raw water

Filtration

Screening

sludge

sludge

Alum

Polymers

Rapid Mix

Disinfection

Cl2

Flocculation

Storage

Distribution

contact filtration
Contact Filtration

Raw water

Filtration

Screening

sludge

sludge

Alum

Polymers

Rapid Mix

Disinfection

Cl2

Storage

Distribution

size of major unit processes
Size of Major Unit Processes

Unit Process Parameter Range

Flocculation  10-30 min

Sedimentation Q/As 0.67 m/hr

Filtration Va2.5 - 37 m/hr

Los Angeles - _______

NYC considering 15 - 30 m/hr (likely 25 m/hr)

37 m/hr

backwash requirements

U

FB

B

Backwash Requirements

Total filter bed area

Useable production (or area)

Production used forbackwash

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

36.4 ha site

ha=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
area of flocculation tanks
Area 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
summary
Summary
  • 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
Supply Aqueducts and Tunnels

Catskill Aqueduct

Shandaken Tunnel

Delaware Aqueduct

Neversink Tunnel

East Delaware tunnel

West Delaware tunnel

kensico to hillview

Catskill

Aqueduct

Delaware

Aqueduct

Kensico to Hillview
possible filtration plant site22
Possible Filtration Plant Site

90 acre site

36.4 ha

ha=10,000 m2

Close to Catskill and Delaware Aqueducts

1 km