Drinking Water:
Challenges and Solutions for the
Next Century
Mark W. LeChevallier, Ph.D.
Director, Innovation & Environmental Stewardship
American Water is the largest water
and wastewater services provider in
North America, headquartered in
Voorhees, NJ.
American Water provide services to
approximately 15 million people in
more than 1,600 communities in 32
states and in Ontario, Canada; and
employs nearly 7,000 water
professionals.
American Water owns or operates
nearly 400 drinking water systems
and 300 wastewater facilities.
We treat and deliver over a billion
gallons of water daily
www.amwater.com
The company conducts over one
million water quality tests each year
for over 100 regulated parameters,
and up to 50 types of water-related
tests each day.
2
#1. Climate Change
•
Changing weather patterns
•
Higher surface air temperatures
•
Melting of polar ice caps
•
Longer, more frequent droughts
•
Shorter, higher intensity rainy seasons
•
Variation in water quality, pathogen loading
•
Rise in ocean levels causing salt water intrusion, habitat
destruction, and displacement of significant human and animal
populations
3
Inventory of AW’s 2007 Green House Gas Emissions
Emissions Source
Emissions (tons
Carbon Dioxide
1
Equivalents)
Emissions (%)
Direct Emissions
Stationary combustion: boilers, generators, …
35,010
3.9%
Mobile sources: fleet
27,156
3.1%
56
0.0%
1,754
0.2%
824,779
92.8%
888,755
100.0%
Process/fugitive: biogas leakage from WWTPs2
Refrigerant: leakage from A/C units2
Indirect Emissions
Electricity
Total
1. Emissions in metric tons CO2e includes CO2, N2O and methane emissions
2. Emissions from flared methane gas and HVAC were both <0.5%
4
How Much Electricity Does the Water Industry Use?
•
Drinking water and wastewater consume:
 3% of domestic electricity1
 7% of worldwide electricity
 19% of California electricity2
1.
2.
3.
•
Water utility energy use varies widely from 0.25 to 3.5 kWh per
1,000 gallons of drinking water produced and delivered3
•
The median 50% of water utilities serving populations >10,000 had
electricity use between 1.0 and 2.5 kWh/1,000 gallons3
Electric Power Research Institute (Burton 1996)
Energy Down the Drain: The Hidden Costs of California’s Water Supply
AwwaRF 91201.Energy Index Development for Benchmarking Water and Wastewater Utilities
5
Emerging Technologies Use More Energy
New regulations are increasing the use of the following,
energy intensive treatment processes:
Added Technology
Additional Energy
• UV Disinfection
• Ozone
• Membranes
Nano and RO
Ultrafiltration
Microfiltration
70-100 kilowatt hours/million gallons
170 kilowatt hours/million gallons
1,800 kilowatt hours/million gallons
1,000 kilowatt hours/million gallons
100 kilowatt hours/million gallons
6
Pumping Accounts for the Biggest Energy Use
• 85-99% of water treatment plant electric consumption goes to
pumping.
 Raw water & well pumps
 High service pumps
 Filter backwash pumps
 Distribution system booster pumps
7
#2. Infrastructure Integrity
American Society of Civil Engineers:
 Each day, approximately six billion gallons of treated drinking water
are “lost” primarily due to system leaks throughout the United States.
 This is approximately 14% of the nation’s total daily water production.
American Water is responsible for 44,000 miles of main.
8
MLOG Acoustic Monitor

Installed near a water meter. Easily
strapped to service pipe or meter.

Maintenance-free, can survive meter pit
environment.

Battery Life – Radio MLOG 8 years and
Fixed Network 15 years.

Fixed Network AMR sends data to host, to
Website daily. Mobile Units, a separate
controller unit acquires up to 11 days of
history.

Proposed Future Unit –Low Cost Unit at
Every Meter
9
10
•
A pilot study of 500 MLOG
units in Connellsville, PA has
reduced 50% of the annual
non-revenue water loss within
the first few weeks of
monitoring. Estimated payback in 6-8 months.
•
Finding leaks in the City of
Connellsville, PA like this
pinhole leak in a cast iron
pipe under a concrete sewer
pipe.
•
Research will evaluate whether most winter breaks are
actually unseen leaks that can be repaired before the
disruptive main break event ever begins
11
Infrastructure Assessment
•
19 of the 40 leaks were identified by acoustic monitors and repaired in
advance of surfacing. Another 6 were MLOG identified before surfacing but
appeared before repair made. The remaining 15 surfaced and were
repaired.
We
can higher
Definite
anticipate
noise in leak
occurring
extremes after
of
Each point represents the start of a main or service in Connellsville
aheat
water
and cold.
temperature
Thereinare
drop
surface
patterns
supply that
repeat annually.
systems.
Optimum time
for leak
detection
Water temperature of surface water near plant
appears to be
the fall.
12
13
#3. Distribution System Integrity
• The hydraulic integrity of a water distribution system is defined
as its ability to provide a reliable water supply at an acceptable
level of service—meeting all demands for adequate pressure,
fire protection, and reliability of uninterrupted supply.
 The most critical component of hydraulic integrity is adequate pressure
defined in terms of the minimum and maximum design pressure.
 A second element of hydraulic integrity is the reliability of supply,
which refers to the ability of the system to maintain the desirable flow
rate even when components are out of service.
14
Example: Pressures Transient
Negative for > 16 sec;
as low as –10.1 psi (-69 kPa)
Gullick et al. 2005. J. Water Supply & Technol. – AQUA 54(2): 65-81.
Separation from Sewer Lines
 Typical separation distance: 10 feet (3 m)
 Standards allow for minimum of 18 in. (0.5 m) separation
16
Backflow Sensing Meters – West Virginia
 Low level event >0.10
gallons of backflow in any
15 minute interval
■
■
≥ 0.1 gallons
≥ 10 gallons
 High level event >10.0
gallons in any 15 minute
internal
 In one 35 day data set
there were 199 events
(5.1%) in 3900 customers
Main
Break
─163 locations with low
level backflow (4.2%)
─36 locations with high
level backflow (0.9%)
17
Field Test Results – Pennsylvania

Installed >3,300 meters

Found 51 instances of
backflow in 1 month
 13 instances of >10 gal
 38 instances of 1-10 gal

Pattern indicative of main
break or pump shutdown

Several isolated spots
warrant further investigation:
 Possible tampering
 Private wells
18
Backflow Occurrence Rates
New Jersey
Month
September
November
December
February
March
April
May
June
July
Total
# Meters
142
143
147
151
149
150
151
148
195
1,376
# Positive
4
3
2
2
2
2
1
2
4
22
% Positive
2.8
2.1
1.4
1.3
1.3
1.3
0.7
1.3
2.1
1.6
Unique Premises
# Positive % Positive
4
2.8
3
2.1
0
0
0
0
0
0
0
0
0
0
1
0.7
2
1.0
10
5.0
19
Backflow Occurrence Rates
Pennsylvania
# Meters
Read
# Positive
% Positive
April
3718
53
1.43%
53
1.43%
May
3714
94
2.53%
42
1.13%
June
2302
27
1.17%
16
0.70%
July
2445
13
0.53%
3
0.12%
August
5217
108
2.07%
84
1.61%
17,396
295
1.70%
198
1.14%
Month
Total
Unique Premises
# Positive % Positive
20
Backflow Occurrence Rates
West Virginia
Month
# Meters
Read
#
Positive
%
Positive
Unique Premises
# Positive % Positive
Aug-06
3923
199
5.07%
199
5.07%
Jun-08
4265
40
0.94%
38
0.89%
Jul-08
4265
23
0.54%
9
0.21%
12,453
262
2.10%
246
1.98%
21
Automating Backflow Alarms
 As part of our AwwaRF AMI
research project, backflow
reports are generated from daily
reads
Backflow events per customer 7/1/08-9/30/08
(4,000 accounts 6-hour time intervals)
45
Number of Backflow Events
 Advanced Metering
Infrastructure (AMI) and
metering systems can work
together to send backflow alarm
immediately after indicator is
detected.
40
35
30
25
20
15
10
5
0
1
 Over a 3-month period some
locations experienced backflow
39 to 41 times
4
7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76
Customers
22
#4. Security

Since 9/11 there has been heightened interest
in how water systems could be compromised
through terrorist attack or accident.

Collaborative project with the USEPA and
the USGS to evaluate multi-parameter
on-line sensors.

YSI (Yellow Spring Instruments) provided the
6920DW probe that measures temperature, pH, specific conductance,
ORP (oxidation-reduction potential), turbidity, and free chlorine.

18 units were deployed in the NJ American, Delran distribution system
and linked by telemetry to the SCADA system. Between 110,000 and
220,000 data points collected.
23
Sensor
Temp
Calibration
Frequency
Never
Typical
Variability
None
SC
Never
± 5 μS/cm
ORP
3 months
Chlorine
4 weeks
0.05 mg/L
pH
4 weeks
± 0.1
Turbidity
8 weeks
± 0.5 NTU
DO
3 weeks
± 10%
20 mV
Comments
Stable, reliable, cannot be adjusted.
Rarely needed calibration.
Stable, reliable and no failures at any
site.
Rarely needed calibration.
Responsiveness declined with time
due to platinum electrode oxidation.
Rarely needed calibration and no
membrane failures.
One meter failed (electronic problems)
Probes required 0.5-2 hr to stabilize
after calibration. About 8 probes failed.
Not sensitive in the range (0-1 NTU)
for distribution system monitoring.
Four probes failed.
Membranes failed after 40-60 days,
sooner in source water, about 6
probes failed.
24
Sensor Location
Practical Locations
Optimal Locations
USEPA TEVA model used
Monte Carlo simulations for
various scenarios:




Contaminant concentration
Injection site
Duration (or rate) of injection
Exposure
All non-zero demand nodes assumed to
be equally vulnerable to introduction of
the biological or chemical contaminants.
Time delay from detection to
implementation of a mitigation response
assumed to be zero.
25
Public Health Benefits with Various Sensor Designs
Site
Response delay
Mean Infections
Reduction in
Health Risks
-
10,427
-
7 practical sites
None
7,289
30.1%
7 optimal sites
None
1,852
82.2%
9 practical sites
None
5,273
49.4%
7 optimal + 2
practical sites
None
1,796
82.8%
7 practical sites
12 h
8,642
17.1%
7 optimal sites
12 h
6,148
41%
No Sensors
26
#5. Water Quality Risk Modeling
• Quantitative Microbial Risk Assessments (QMRA) is a
powerful tool for organizing and assessing microbial data.
• American Academy of Microbiology Report:



The greatest value in microbial risk assessment is in the
development of the model – not necessarily in the final answer.
Proper application of microbial risk assessments can be valuable
in guiding selection and application of treatment processes
The microbial risk assessment process is iterative – there is not
single start or ending point.
27
QMRA for negative Pressure Transients
IDENTIFY
INRUSION
LOCATIONS
Set initial
pathogen conc.
at intrusion
locations
Determine pathogen
transport
Determine combined pathogen
concentration at each node
Calculate customer’s
infection risk
28
Coincidence of Transient and Consumption
1L
Intrusion


Duration = 16s
avg flow before
transient period = 36 gpm
38 L
People consuming water over 1 hour period, would have a 0.4%
(16/3600) probability of drinking contaminated water
Therefore, the
duration of the
transient is
important!
29
#6. Wastewater Infrastructure

The physical condition of the nation's 16,000 wastewater
treatment systems is poor, due to a lack of investment in
plant, equipment and other capital improvements.

Aging wastewater management systems discharge 850 billion
gallons of untreated sewage into U.S. surface waters each year.

Sanitary sewer overflows (SSOs), caused by blocked or broken
pipes, result in the release of as much as 10 billion gallons of
raw sewage yearly

The EPA estimates that the nation must invest $390 billion over the next 20
years to replace existing systems and build new ones to meet increasing
demands.
American Society of Civil Engineers – www.asce.org/reportcard
30
Electroscanning

Simplified Electrical System
Voltage
source
Surface
Electrode
Breaks provides
low resistance
Pipe full of water
Cable
Pipe wall
provides high
resistance
Sonde
31
24
0.16in(4mm) wide, 4in long
Transverse slot
0.16in(4mm) wide, 8in long
22
Transverse slot
20
0.16in(4mm) wide, 12in long
18
Transverse slot
3.9, 3.1 and 2.4in long
12
14
16
Distance from Center of Start MH(ft)
0.16in(4mm) wide
Three transverse slots 4in apart
0.16in(4mm) wide, 2.4in long
Two transverse slots 2in apart
0.16in(4mm) wide, 8 in long
Longitudinal slot
10
0.16in(4mm) wide, 8 in long
8
Longitudinal slot
6
0.16in(4mm) wide, 4in long
4
Two transverse slots 2in apart
2
Circular hole, diam 0.39in(10mm)
0
Circular hole, diam 0.24in(6mm)
Circular hole, diam 0.24in(6mm)
Electrode Current
20
Electroscanning Pipe Trace
15
10
5
0
26
32
Electroscanning is more Effective than Conventional CCTV
Type of Anomaly (All Materials)
Leak Causing Defects
Defective
Faulty
PipeService
Manhole
Connection Connection
Report
Joint Defect
#
CCTV
#
82
Electroscanning
Longitudinal Crack
488
ft
7
20
Transverse
Crack
Low Level
Corrosion
#
103
147
#
19
33
Other Defects
13
487
Protruding
Taps
Major
Structural
Damage
Sag
#
#
#
#
3
63
0
10
9
10
Interpreted Interpreted
as corrosion as cracks
34
0
Compared to CCTV, Electroscanning was
More effective:
Lower cost:
Greater productivity:
1.7 to 21 times
50 to 80% less
30 to 50% greater
33
Wastewater Infrastructure Cost Model
Cost Effectiveness of I/I Control
$30,000,000
$25,000,000
NPV
$20,000,000
$15,000,000
$10,000,000
$5,000,000
$0
0
0.5
1
1.5
2
2.5
3
Flow Reduction, MGD
Total Cost $
Investment
Treatment and Collection
34
#7. Reuse of Treated Wastewater
•
Water reuse in the U.S. is a large and
growing practice
•
Nationally, an estimated 1.7 billion gallons
per day is reused.
•
Reclaimed water use on a volume basis is
growing an estimated 15% per year.
•
In 2002, Florida reclaimed 584 mgd.
California ranked a close second with 525
mgd used daily.
•
Florida has an official goal of reclaiming
1 billion gallon per day by the year 2010.
•
Other leaders: Texas, Arizona, Nevada,
Colorado, Georgia, Washington
35
Sites 23 and 24
Millennium Towers
Tribeca Green
Visionaire
Solaire
River House
36
Tribeca Green
19B
The Solaire
Site 18A
Visionaire
Site 3
Sites 23 & 24
Riverhouse 16/17
Millennium Tower Site
2A
37
Sewer Mining: Immediate Benefits
•
Enhances collection system capacity
•
Increases drinking water supply reliability
•
Minimizes infrastructure requirements

Reclaimed water distribution requirements kept at a minimum

Saves on pumping costs of reuse water
•
Enhanced Sustainability
•
Waste Activated Sludge to collection system
•

Improves odor control

In-pipe treatment
Provides planning, operating and capital investment flexibility

Tailored Treatment
38
#8. Desalination
•
Worldwide, the desalination market soared from $ 2.5 bn
in 2002 to $ 3.8 bn in 2005 with a growth rate over 15%
per annum.
•
Over 50% of the US population live in coastal areas.
•
Frost & Sullivan reports that the "U.S. Desalination
Pretreatment Market" will double from $184.0 million
in 2005 to $399.6 million in 2012
•
Key issues:





Brine Disposal
Pretreatment (biofouling)
Energy Conservation
Productivity
Operational Experience
39
And California too…
Moss Landing, Monterey
Carlsbad Desalination Plant
40
Control of Membrane Fouling
•
In drinking water the presence of assimilable organic
carbon is known to be associated with growth of biofilms
•
Development of a bioluminescence AOC test has
permitted rapid, low cost, measurements

Development of a salt-water test can evaluate the
effectiveness of desalination pre-treatment processes
Comparison: Multiple substrate model & actual data (NOX)
10,000,000.0
1,000,000.0
Luminescence
•
Application for reclaimed waters
100,000.0
10,000.0
1,000.0
100.0
0.0
10.0
20.0
30.0
40.0
Time (hours)
50.0
60.0
70.0
80.0
41
#9. Energy – Water Nexus
The U.S. Energy Policy Act of 2005 established the DOE’s role in
energy and water related issues.
The DOE’s Sandia National Lab states that:



Energy and Water are inextricably linked
That link is vital to U.S. security
and economic health
The nation’s ability to continue providing
both clean, affordable energy and water
is being seriously challenged by a number
of emerging issues
42
Water Use for Mining of Oil, Gas, and Coal
Mon River quality up after limits on drillers
By The Tribune-Review Thursday, January 22, 2009
State concerned about waste water from new
gas wells
Sunday, December 21, 2008 By Don Hopey, Pittsburgh Post-Gazette
43
Canal Road Solar Array, NJ
590 kW ground-mounted photovoltaic system
Produces 687,000 kilowatts of energy / year
Eliminates 493,835 pounds (224 metric tons) of CO2e per year
44
Bioenergy Recovery
•
Widely used with natural gas
•
Increased number of
applications for Digester Gas
•
Typical Applications for
Digester Gas

Power to the Electric Grid
(Green Power- RECs)

Heat to heat digestion process

And Building HVAC

Documented case studies for:
Fuel Cells, Microturbines,
Combustion Engines
45
Co-Location with Landfill Biogas
Raw Water Pump Station
•
Landfill located two (2) miles from water
pumping station
•
The landfill currently is flaring its methane
•
The pump station uses close to 500 kW of
electric power
•
The pump station has an emergency power
generator to run on natural gas
•
Easy conversion of generator to biogas
•
Landfill has 10x more gas than needed to
run the generator
Landfill
46
#10. Alternative Delivery Systems
• In 100 years will anyone drink piped water?
• In a hydrogen economy water will be a by-product
of energy production
 Drinking water is already produced
on the space station
• Water companies will be stewards of the water cycle
and protectors of the environment
 Transition from public health protection
to environmental protection
 Communicate the value of water
47
Conclusion
• This is an exciting time to work in the water industry
• Challenges provide opportunities for innovative solutions
• The aging water industry workforce will require new
professionals
10-15% of engineering and other technical and scientific
professionals will retire in the next 5 years
• Students should consider an exciting, challenging, and
immensely rewarding career in the water industry
• The work that you will do will save lives, protect public health,
and protect the environment; at same time as providing a vital
and necessary service.
• Maybe that’s the final challenge!
48
Thank you for your attention!
Acknowledgements
Support was provided by the utility
subsidiaries of American Water
Contact Information
Mark W. LeChevallier, Ph.D.
Director, Innovation & Environmental
Stewardship
American Water
1025 Laurel Oak Road
Voorhees, NJ 08043 USA
phone: (856) 346-8261
fax:
(856) 782-3603
e-mail: mark.lechevallier@amwater.com
49