Groundwater Under Direct Influence of Surface Water, What To Do?

Transcription

Groundwater Under Direct Influence of Surface Water, What To Do?
Groundwater Under Direct Influence of
Surface Water, What To Do?
Presented by:
Michael S. Johnson, P.E.
Buck, Seifert & Jost, Inc.
Presented at:
American Water Works Association (AWWA)
Annual Spring Conference, Atlantic City, NJ
March 17-20, 2015
Outline
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LT2ESWTR
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Treatment Techniques
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EPA
Factors that trigger
compliance
UV, Filter, Chemical, etc.
Case Studies
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Two (2) wells
Start up/Operation
Procedures
Background
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LT2ESWTR
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Improve drinking water quality
Protection from disease causing
microorganisms and contaminants
Applies to all PWS that use SW or GWUDISW
GWUDISW Factors (varies by state)
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Type of well (spring, horizontal collection well,
unconfined aquifer or recharge well)
Adjacent to surface water
Well Construction (shallow/deep, annular space)
Water Quality (periodically +TC or +E. Coli)
Background
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Hydrogeological Investigation
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Hydraulic connection (seismic reflection survey, seepage
investigation, or thermal infrared imagery)
Microscopic Particulate Analysis (MPA)
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Low, Medium, or High Risk
Algae, Diatoms, Pollen, Protozoa, Giardia, Crypto, etc.
You, after Medium or High Risk MPA?
LT2 Rule
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2-log Crypto (or 5.5 if raw water not monitored)
3-log Giardia, and
4-log Virus
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Treatment Options
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Watershed Control
Alternative Source/Intake
Bank Filtration
Pre-sedimentation
Lime Softening
Filter
Chlorine Dioxide
Ozone
UV
Membrane Filtration
Filters
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Refer to State Standards
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Bag and Cartridge Filters
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Operator licensing
Low Loading capacity for small systems
Discard filter after expended
Effectively removes Crypto (2-5 μm)
and Giardia (5-10μm)
Challenge Testing
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Product specific, not site specific
o
o
o
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Full scale
Challenge particulate
Test solution concentration
Up to 2 log for bag or cartridge filter showing 3 log removal
Up to 2.5 log removal in series showing 3 log removal
Filters
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Advantage
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Low maintenance, low capital,
minimal training
Disadvantage
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NSF, Headloss, Replace filters,
redundancy, biofilm clogging, limit
surges, larger flows consider
membrane or other
Filters
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Turbidity < 3NTU or less depending on
manufacturer, may need pre-treatment
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UV treatment may require pre-treatment
if >1 NTU
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MPA proof after installed?
Ultraviolet (UV)
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Damages microorganisms and prevents replication
No residual
Validation testing, see UV Disinfection Guidance Manual
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In English
Partial Exhibit 13.1 UV Dose Requirements – mJ/cm2
Ultraviolet (UV)
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Two (2) types of UV devices typically
used:
1. Medium Pressure (MP) and
2. Low Pressure High Output (LPHO)
More information see Ultraviolet Disinfection
Guidance Manual at:
http://www.epa.gov/OGWDW/disinfection/lt2/
pdfs/guide_lt2_uvguidance.pdf
Ultraviolet (UV)
LPHO vs. MP
 Reactors can be s-shaped, u-shaped, or in-line
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Lamp life
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LPHO 8,000 to 12,000 hours
MP 4,000 to 8,000 hours
Power
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Typically LPHO require larger footprint
LPHO require less power, more lamps
Sleeve Cleaning
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LPHO use Off-line chemical clean (OCC) systems, more
labor
MP use On-line Mechanical (OMC) systems, more parts to
replace
Ultraviolet (UV)
Examples of:
S-Shape
U-Shape
In-line
Ultraviolet (UV)
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Validation of UV device
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No increasers US or DS within 10 times diameter of reactor
PWS monitor for flow rate, lamp status and UV intensity
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UV absorbance (or UVT) if in dose monitoring strategy
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Fouling: Ca+2, Alkalinity, Mn+2, pH, Fe+2 and Hardness
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Off-spec reporting
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Advantages: Lowest cost treatment for Crypto and Giardia,
no DBP, not impacted by pH or temperature
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Disadvantages: no residual, high UV dose for Virus
inactivation, power quality
Full Scale Implementation
 Example 1
 200gpm well @ 360TDH,
200’ Deep Well
 12’ x 22’ Wellhouse
 Seaquest and Hypo
 Wetlands nearby
Prior to Construction
 From Determination of
GWUDISW, 18 Month
Schedule To Implement
Full Scale Implementation
As Constructed
Construct within existing
building
New 200gpm @ 454 TDH VTP
Waste/blow off piping
Harmsco MUNI-3-3FL
Full Scale Implementation
As Constructed
Harmsco
MUNI-3-3FL
InLine 200+ DVGW
UV
6”x6” Tee
Flow meter
Surge Antic. Valve
M.O. Spring Return
BFV
35LF of 36ӯ DIP
Full Scale Implementation
Example 2
 1200gpm well @
609TDH, 55’ Deep Well
 16’ x 13’ Wellhouse
 Seaquest and Hypo
 Floodplain and High
Pressure
 From Determination of
GWUDISW, 18 Month
Schedule To Implement
Prior to Construction
Full Scale Implementation
Prior to Construction
Full Scale Implementation
Raise All Treatment
Components
New 1400gpm @ 372 VTP
(Lower head)
New Elevated
Treatment Enclosure
Full Scale Implementation
Parallel Treatment Trains
With And Without Grating
Full Scale Implementation
As Constructed
UV Reactor
Y-Strainer
Full Scale Implementation
As Constructed
Surge Anticipating Valve
Spring Return Hydraulic BFV
Booster Pump
Surge Anticipating Valve Vault
Summary
 NSF Listing
 UV Validation
 UV and Filter Treatment: multiple barriers
 Think Vertical
 Start-up and testing
 Learning Process
o We were assisted by and would like to thank:
 Entire staff at United Water special mention to:
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Gerry Remsen, III, P.E.
Bill Prehoda, P.G.
Nick Curcio
Bob Raczko, P.E.
 Sam Rulli, P.E., Rockland County DOH
 Dan Miller, Ph.D, Rockland County DOH
 Brock Rogers, P.E., NYS DOH
 Ronald von Autenried, P.E., BS&J
 J. Fletcher Creamer & Son, Inc. (Contractor)
 Aquionics Inc. (UV)
 Harmsco Filtration Products (Filter)
 Quality Controls, Inc. (Fail Safe BFV)
 Baker Manufacturing Company, LLC (Booster Pump)
Thank you!
Michael Johnson
msj@bsjinc.com
201-767-3111, ext. 111