Croton Water Filtration Plant, New York, USA
Key Data:
Decision to Build
June 2004
Construction Began
2007
Low Bidder Pulled Out
April 2007
Skanska Contract Awarded
August 2007
Construction Duration
50 months
Start-Up Phase
Six months
Project Completion
2012
Capacity
320mgd (1.2 million cubic metres a day)
Proportion of NY Water Demand Supplied
10%
Population Served
One million
Building Footprint
377,000ft² (34,270m²)
Site
12 acres (4.8 hectares)
Main Treatment
DAF / Filtration
Disinfection
UV and Chlorination
Flocculation
2-stage; 144sec/stage minimum
DAF Loading Rate
50gpm
Filter Type
Dual media – 60cm anthracite, 30cm sand
DAF Sludge Treatment
Skimmed solids dewatered by centrifuge
Key Players:
Project Sponsor
New York City Department of Environmental Protection
Main Contractor
Skanska
Additional Contractor
Tully Construction
Geo-Technical Consultants
Haley & Aldrich
Digital Automation Architecture
Emerson
Client Consultant
Hazen & Sawyer / Metcalf & Eddy JV
Indicative Water Quality:
Turbidity NTU
1.1
TOC (mg/l)
2.8
TDS (mg/l)
186
Specific Conductance (umho/cm)
315
Phosphate (mg/l)
2.1
pH (pH units)
7.2
Nitrite
0.002
Nitrate
0.21
Hardness mg/l CaCO3
92
Alkalinity mg/l CaCO3
54.3
Colour (colour units)
12 (distribution system average) 5 – 40 (range)
Post-Filtration Targets:
Giardia Cycts
> 99.9% removal and inactivation
Cryptosporidium
99.9% removal and inactivation
Viruses
> 99.9% removal and inactivation
Filtered Water Turbidity
< 0.1 NTU
TOC
< 2mg/l
True Colour
< 5
Construction Contract Value
$1.3bn
