water supply and treatment evaluations and improvements
TRANSCRIPT
Maintain High WQ
Meet Growth Potential
Protect Water Source
Improve Treatment
Extend Facility Life
Implement Improvements
Project Goals
Evaluation & Implementation Approach
Desktop Study
Preliminary Design
Final Design Bid Phase Construction
Desktop Study - Step-Wise Strategy
Identify Problems
Develop Solutions
Evaluate Solutions
Determine Phased
Path Forward
Scope of Work for Desktop Study
►Demand Reassessment
►Data Review
►Well Field:
• Well capacity
• Firm yield
• Condition assessment
• Measures to control
contamination
►WTP:
• Process evaluation
• Filter evaluation
• Finished water stability
• Regulatory review
• Condition assessment
• Schematic design
• Alternatives evaluation
• Opinion of probable cost
►Report
5
Existing System Capacity
Wells
• 5 active
• 1 inactive
• Up to 3 MGD each
Demand
• Max Day = 5.0 MGD
Result
• Run 2 wells to meet Max Day
Observations
► Specific capacity decline of all wells is normal
• Current specific capacities is still high (100 gpm/ft or more)
► Wells 2A, 4A, and 7 fall into the Design Life category
• These wells can still maintain their design pumping rate
► Well 5 and 6 are into the Life Expectancy category
• Well 6 has been lined due to a structural failure in the casing
• Well 5 is almost 50 years old and has a low specific capacity
► Reliance on Well 6 (pumped almost every day) is a
concern given structural failure
► Model compares very favorably to
real world plume migration
► Well 1A contains ammonia/nitrogen
plume
• 600 gpm
• Capture zone is approximately 1700
feet wide
USGS Model Results
Contaminant Sources and Well Field Contributing Recharge Area
The vast majority of potential contaminant sources are hydraulically
downgradient of your well field
NKC Well Field Contributing Recharge Area
Presence of Lead► 20 Shallow Soil Samples
• One soil sample above MDNR
Residential Target Level (260
mg/kg)
• All below MDNR Non-
Residential Target Level
►Not in Aquifer• ND in 14 groundwater samples
(2009)
► Lead in Soil is Not Mobile
• Only mobile in acidic soils
• Soil pH 7.5 to 10.8 (2009)
► No Data to Support Lead
Contamination of Well Field
1 1
► Update USGS model and update with current well field conditions
• Confirm capture zone
► Operate Well 1 to contain ammonia/nitrate
• Run at 600 gpm
• Breakpoint chlorinate ½ of flow
Well Field Recommendations
Downhole TV Survey –Integrity1
Rehab Well / New 600 gpm
Pump
Depth Related WQ Samples
1If Well 1A has a structural problem, redrill well
Well Field Recommendations
►Add emergency backup
power to South wells
►Redrill Well 6
►Redrill Well 5
►New valve vault for
remaining wells
►Firm capacity will be12
MGD
WTP Evaluations
► Issues:• Electrical System
• SCADA/Control System
• Hydraulic Issues
• Structural / Mechanical /
Architectural Issues
• Chemical Utilization / Feed
• Settled Water Turbidity
• High Service Pump Issues
A Partial Rehabilitation is Recommended!
Treatment Goals
► Hardness removal
► Raw water quality
• Ammonia
• Nitrates / Nitrites
• TOC and VOC
► Disinfection Byproducts
► Future regulatory requirements
• GWUDI Compliance
• Emerging Contaminants
Aerator and Optional Bypass
`
Wells
Upflow Solids Contact Clarifier
(North)
Upflow Solids Contact Clarifier
(South)
Dual Media Filters
Clearwell
High Service Pump Station
Chlorine
Carbon Dioxide
To Distribution System
PrimaryCO2 Recarb
Basin
Raw Water Parameter Sampling
Finished Water Continuous Online Total and Free
Chlorine Measurement
Lime
Optional Bypass for Primary and Secondary Clarifiers
Lime
SecondaryCO2 Recarb
Basin
Phosphate
To Distribution System
StabilizationBasin
Existing Process Schematic
Chlorine
Aerator and Optional Bypass
`
Wells
Upflow Solids Contact Clarifier
(North)
Upflow Solids Contact Clarifier
(South)
Dual Media Filters
Clearwell
High Service Pump Station
Chlorine
Carbon Dioxide
To Distribution System
CO2 RecarbPiping
Raw Water Parameter Sampling
Finished Water Continuous Online Total and Free
Chlorine Measurement
Lime
Optional Bypass for Primary and Secondary Clarifiers
Lime
Phosphate
To Distribution System
StabilizationBasin
Proposed Process Schematic
Chlorine
Well 1 with Breakpoint Chlorination
Chlorine
Evaluations / Observations
► Transformers Service/Parts Issues
► MCCs Service/Parts Issues
► No Pump Local Disconnects
► Genset Configuration – Code
► No South WF Genset
► SCADA Outdated/Lacks Capacity
► Instrument Upgrades
Recommended
Recommendations
► New Pad Mounted Transformer
► New Motor Control Centers
► Add Pump Disconnects – Code
► Reconfigure Ex. Genset
► Add South WF Genset
► New SCADA
► New Instrumentation
Electrical / SCADA
Evaluations / Observations
► Ex. Chlorine gas system
► Code/Safety Issues – no scrubber
► Under-capacity
► Evaluated:
• Gas
• Bulk hypochlorite
• On-site generation
• Comparable 20 year present values
Recommendations
► Ton Container Gas System
► Dry Scrubber
► Use 4000-5000 #/month (avg)
Disinfection (Chlorination)
Evaluations / Observations
► Iron Build-up
► Access
Recommendations
► Replace Internals
► Add Catwalks
Aerator
Evaluations / Observations
► Corrosion on launders and scrapers
► Some corrosion on other
components
Recommendations
► Replace launders and scrapers
► Re-coat basin equipment
Softening Basins
Evaluations / Observations
► Basins Not Required
► Building Structural Issues
Recommendations
► Remove Building
► Demo Basins
► Replace Basins with Piping
► Rebuild Space for Proposed
Electrical/Chemical Building
Recarbonation
Evaluations / Observations
► Backwash flow calibration is
excellent
► Size-matching of sand and
anthracite is good
► Media bed expansion lower than
recommended
► Backwash length shows diminishing
returns
► Top layer of media slightly dirty after
backwash
Recommendations
► No changes recommended for
additional benefit at current capacity
and operating conditions
► Add 2” anthracite
Filter Evaluation
Evaluations / Observations
► Replace Two Pumps
► Replace One Impeller
► Meters Placement Poor
► Raw Meter Out of Calibration
Recommendations
► Replace Pumps 3 & 4
► Replace Impeller in Pump 1
► Add VFDs for Improved Control
► Add Two New Meter Vaults
► Replace Raw Meter
High Service Pumping / Metering
Evaluations / Observations
► Filter Roof Leaks
► Filter Flooring Needs Replaced /
Asbestos
► Rotting Drywall and Ceiling Tiles
► Peeling Lead Paint in Operable
Parts of WTP
► Admin Area Miscellaneous Issues
Recommendations
► Re-Roof Filter Gallery
► Replace Filter Epoxy Floor
► Remove Rotting Drywall and Ceiling
Tiles – No Replacement
► Remove Lead Paint
► Renovate Admin Area
Architectural
Evaluations / Observations
► Structural Supports for Morton
Buildings – Wood Rot
► Miscellaneous Concrete and
Masonry Repairs Required
► Access and Safety Thru Plant
► Poor Loading Dock Access
Recommendations
► Replace Columns for Softening
Basins and Demo Recarb Basins
► Repair Concrete and Masonry
► Add Catwalks and Handrail – Code
► Extend Loading Dock 12’
Structural
Evaluations / Observations
► Make-up Air Units, Air Supply and
Exhaust Fans Life Exceed
• Basement
• Admin Area
• Solids Contact Basin Area
• Filter Gallery
► Hot Water Heater – Life Exceeded
Recommendations
► Replace Make-up Air, Air Supply and
Exhaust Fans
► Replace Hot Water Heater
Mechanical
Evaluations / Observations
► Two units
► Require attention / maintenance
► Not able to achieve optimal conditions• Temperature
• Water/lime ratio
• Reaction time
Recommendations
► New equipment will reduce lime use
10%
► New lime equipment is priority 2
Lime Slaking
Residuals
Continued
Discharge to
Missouri River► MDNR Coordination
• Anti-Degradation Study
• Professional Judgment Analysis
► Solids Loading <= Current
► No Visible Discharge in River
Residuals
Continued Discharge to Missouri River
► Surge Basin / Dilution
► Dechlorination /
Metering
► Connect to existing
outfall system
► Other Alternatives
Figure 7-1: Proposed Chlorine Gas Location and
Layout (Ton Cylinders)
M
M
M
SCRUBBER
ELECTRICAL
EQUIPMENT AND
BREAKPOINT PIPING
FEED ROOM
STORAGE
ROOM
TRANSFORMER GENERATOR
3 2
Opinion of Probable CostItem Cost Priority 1 Priority 2
Well 1 240,000 240,000
Well 6 580,000 580,000
Chlorine (WTP + Breakpoint): 2,000,000 2,000,000
CO2 610,000 610,000
Aerator 300,000 300,000
Solids Contact Basins 463,000 463,000
Filter Media 80,000 80,000
Filter Valves 670,000 670,000
High Service Pump Station / Meter
Vault / Raw Water Meter 1,130,000 1,130,000
Chemical Changes 190,000 190,000
Electrical - WTP & N. Well Field 1,400,000 1,400,000
Electrical - S. Well Field 560,000 560,000
Structural 1,690,000 1,690,000
Architectural 1,040,000 1,040,000
Mechanical 1,190,000 1,190,000
Civil 140,000 140,000
Well 5 760,000 760,000
Well 2A, 4 & 7 Vault Improvements 590,000 590,000
Lime: 3,590,000 3,590,000
Total 17,223,000 13,633,000 3,590,000
Next Step – Preliminary Design
Funding AgreementComplete within 6 months
Final Design Bid PhaseConstruction
Phase