north system renewal water treatment plant project...
TRANSCRIPT
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North System Renewal Water Treatment Plant Project (NSRWTP)
Presented by: Zack Alabbasi and Andrea Song
JTAC LuncheonMay 15, 2014
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History of Moffat WTP
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• David Moffat (July 22, 1839 – March 18, 1911)
• Born in Washingtonville, New York.
• Moved to Denver in 1860.
• Formed a railroad company in 1867 to link Denver to the national rail network.
• Denver relied on rivers, ditches and wells until about 1872, when a private water company was franchised. Kassler Plant (first plant) was built in 1890.
• Soon, several water companies were operating in the city. In 1894 they were consolidated as the Denver Union Water Co., headed by Walter Cheesman and David Moffat.
• The citizens of Denver purchased the company in 1918 for $14 million dollars (bond issue).
History of Moffat WTP
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• A vision of David Moffat, the Moffat Tunnel (linking Denver to Salt Lake City and the west coast) was a railroad and water tunnel.
• Cost $24 million and 28 lives to build.
Benefits of the Moffat Tunnel as outlinedin Nov 1922 issue of Popular Science magazine
• The first train passed through the tunnel in February 1928. The 6.2 mile tunnel shortened the distance between Denver and the west coast by 176 miles.
History of Moffat WTP
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History of Moffat WTP
Moffat Water Treatment Plant 1930s10 filters – 50 MGD capacity
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Mayor Stapleton commissioning the Moffat Water Treatment Plant in 1937
History of Moffat WTP
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Filter plant 1 (1937): 10 rapid sand filters. Total capacity = 50 MGD
Filter plant 2 (1955):10 rapid sand filters. Total capacity = 75 MGD
Filter plant 3 (1974):8 rapid sand filters. Total capacity = 60 MGD_______________________________________________
Total capacity = 185 MGD
History of Moffat WTP
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Water Source (Denver Water)
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Gross Reservoir
Outlet at Gross Reservoir
Ralston Reservoir
The Upper Williams Fork and Fraser River basin supply Gross reservoir (through the Moffat tunnel)
Gross reservoir supplies Ralston Reservoir (through South Boulder Creek)
Ralston Reservoir supplies Moffat WTP via conduits 16 and 22
Water Source (Moffat WTP)
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Gross: 41,811 acre-foot or 13.6 billion gallons
Ralston: 10,776 acre-foot or 3.5 billion gallons.
Ralston reservoir is 6046 ft. (full)Ralston valve is 5950 ft.Van Bibber is 5840 ft.Moffat is 5623 ft
96 ft110 ft
217 ft
423 ft = 183 psi
Storage Capacity (Moffat WTP)
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RalstonReservoir
UpperLongLake
lowerLongLake
Ralston Reservoir
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Conduit 16 is 42-inch concrete pipeline constructed in 1937.
Conduit 22 is 54-inch concrete pipeline constructed in 1950.
Raw Water Transmission Pipes
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Aluminum Sulfate (Alum) CoagulationPotassium Permanganate OxidationCalcium Hydroxide (Lime) pH adjustmentCarbon Dioxide Alkalinity, and
pH adjustmentDADMAC (Cationic polymer) Coagulation-aidPolyacrlyamide (Nonionic polymer) Flocculation-aid,
filter-aid and sludge de-watering
Sodium Silicofluoride (Fluoride) FluoridationSodium Hydroxide (Caustic Soda) pH AdjustmentChlorine DisinfectantAmmonium Hydroxide (Ammonia) Disinfection aid
Treatment Chemicals
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Treatment Process
RalstonReservoir
GravityThickener
Waste ResidualSolids
Spent Backwash
Drying Lagoons
(Ralston)
Landfill
Gra
vity
Thi
cken
er S
uper
nata
nt
Supe
rnat
ant/o
verf
low
(occ
asio
nal)
BackwashEqualization
Basin
Spen
t Bac
kwas
h
South Boulder Canal
Off-site Disposal
Flocculation / Sedimentation
Distribution System
DisinfectionContact Basin
Finished WaterStorage
Filtration
Filtration
Drain
Drain
RapidMix
Floc/Sed Drain
Pump Station
Pump Station
Filter to waste
Filter Drain
Alum, Lime, Carbon Dioxide, Potassium Permanganate, Polymer Polymer
Polymer, Chlorine
Chlorine, Fluoride, Ammonia, Caustic SodaPolymer
Aeration
Drying Lagoons
(41st & Independence)
Clear Creek
Plant drainage, Storm water
Dechlor
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Treatment Process
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North System Renewal Program
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Future of Moffat WTP
North System Renewal Program:
• Raw Water Collection System (Gross Reservoir Expansion)
• Ralston Reservoir Multi-Level Outlet
• Conduit 16 Replacement
• North System Renewal Water Treatment Plant Project (NSRWTP)
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North System Renewal Water Treatment Plant Project (NSRWTP)
• Rebuild of the Moffat WTP
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Why Moffat TP? Why Now?
• Parts of Moffat reaching end of its useful life
MOFFAT FILTER GALLERY
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Why Moffat TP? Why Now?
31”
MOFFAT WTP MONO MEDIA
20”
4”4”3”
42”
MARSTON WTP DUAL MEDIA
34”
8”
• Current Technology– Dual Media Filtration
• Outdated Technology– Mono Media Filtration
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Moffat WTP Through the Years
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Road Map for NSRWTP
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Program Schedule for NSRWTP
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Plant Site Selection
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Moffat Site - Property Owned by DW
Moffat TP Site~ 40 Acres
YMCA Site~ 8 Acres
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Ralston Site~ 1,033 Acres
Ralston Reservoir Site - Property Owned by DW
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Plant Site Selection
• Determine the best course of action:
RALSTON SITE?MOFFAT SITE?
OR
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Moffat Preliminary Evaluation
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• Parts of the plant reaching end of its useful life.
• Outdated filtration technology (mono media filtration).
• Replace Moffat TP in a planned manner To plan and adjust long range capital budget Consider needs of all stakeholders
Evaluation Process:
• Two locations (Moffat and Ralston) and two treatment technologies are considered in the evaluation (dual-media, membrane, hybrid).
• Condition Assessment (existing plant), Cost Comparisons (both sites and both technologies), Non-Monetary Criteria (both sites)
• 250 MGD capacity
Moffat Site - Dual Media Filtration
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Reservoir 3
Reservoir 2
Moffat Site - Dual Media Filtration
KEY:
PHASE 2PHASE 1
FUTUREPHASE 3
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Moffat Site - Dual Media Filtration
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Ralston Preliminary Evaluation
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Proposed Construction Site
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Ralston Site - Dual Media Filtration
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Ralston Site - Dual Media Filtration
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The Numbers - Comparison
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The Numbers - Comparison
$370,000,000 Construction Cost
6 Years of Construction
~15,000 Truckloads of material & equipment
108,600 CY Concrete poured
91,500 CY Backfill
85,600 CY Excavation
47,280 CY Concrete demo and crushing
$444,000,000 Construction Cost
3.5 Years of Construction
~22,000 Truckloads of material & equipment
178,200 CY Concrete poured
614,000 CY Backfill
>1,000,000 CY Excavation
Moffat 250 MGD – Dual Media Ralston 250 MGD – Dual Media
0 CY Concrete demo and crushing
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Monte-Carlo Analysis
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Treatment Process Selection
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North System Renewal Water Treatment Plant Project (NSRWTP)
• Developing WQ goals for treatment process selection
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Developing WQ & Treatment Goals for NSRWTP
• Technical Panel• CU, CSU, Mines• WRF Wildfire Study
• Future Uncertainty• Gross Reservoir Expansion• Extreme weather events
• Adopted Partnership for SafeWater Goals
Debris in StrontiaSprings Reservoir after Hayman Fire
2002
Gross Reservoir atheight of drought
2002
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Storm Event of September 2013
• Lessons learned will be incorporated in future plant design standards
Ralston Reservoir Flood 2013
Slide Area Auxiliary Spilllway
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• Think beyond the WTP• Expanding reservoir monitoring program
• Source Water/Distribution System Evaluation
GROSS RESERVOIR
Storm Event of September 2013
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• Completing desk-top evaluations and then fast and economical bench-scale tests
• To help narrow down treatment alternatives for pilot testing
Treatment Process Selection for NSRWTP
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Current Treatment Process Train
Cl-NH3
Finished Water
DisinfectionRapid-Mix &
FlocculationSedimentation
Granular Media Filter
Raw Water Intake
Wat
ersh
ed C
ontr
ol S
trat
egy
CoagulantPolymer
pHAlkalinity
Fluoride
pH Corrosion Inhibitor?
Treatment Process Selection for NSRWTP
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Enhanced CoagulationBiological Filtration
Raw Water Intake
Watershed Control Strategy
Riverbank Filtration Watershed
Master Plan
Cl-NH3
DisinfectionRapid-Mix &
FlocculationSedimentation
Granular Media Filter
CoagulantPolymer
pHAlkalinity
Fluoride
pH
Corrosion Inhibitor?
Pre-coagulant
Ozone
Finished Water
Settled Water Ozone
UV orOzone
OrMF/UF
MembraneGAC
Future Treatment Process Train
Treatment Process Selection for NSRWTP
AOP(Peroxide)
AOP(Peroxide)
AOP(Peroxide)