system optimization during system design and operation...
TRANSCRIPT
System Optimization During System Design and Operation to Enhance Conventional Remediation Technologies
Chuck Whisman, PE
Sr. VP of Engineering – Groundwater & Environmental Services, Inc. (GES)
Exton, PA - USA
Remediation System Optimization
Definition:
> To evaluate and monitor remediation systems to detect and respond to changes in system performance
> To determine if system enhancements are needed to meet remedial objectives or improve system operation
Benefits:
> Reduced O&M duration
> Project life-cycle cost savings
The Optimization Process …
Cost savings realized for each month of O&M reduced:
> Labor (field and office)
> Materials (filters, carbon, …)
> Utilities and fuel
> Monitoring (system and wells)
> Equipment lease/rental
> Off-site disposal fees
> Administrative costs
How Much $ Can Effective System Optimization Save?
Typical Remediation System Typical Optimized System
Design $ 10,000 $ 12,000
Installation $ 150,000 $ 165,000
Year 1 O&M $ 70,000 $ 75,000
Year 2 O&M $ 70,000 $ 75,000
Year 3 O&M $ 70,000 $ 75,000
Year 4 O&M $ 70,000 ---
Year 5 O&M $ 70,000 ---
TOTAL $ 510,000 $ 402,000
Does not include post-remediation monitoring/closure costs.
Annual O&M costs include groundwater monitoring and utility costs.
The Optimization Process During Design
• Effective site characterization and feasibility testing will
minimize design assumptions.
• Optimization features can be designed into the system
(i.e., remote monitoring controls, specific equipment,
sampling locations).
The Optimization Process During Design
Examples of design modifications to provide more effective
optimization
> Remote monitoring systems - view data & adjust operation
> Using high-efficiency extraction/injection wells
> Utilizing individual lines to injection/extraction wells (improves
data review and ability to modify system)
> Equipment selection (i.e., redundant transfer pumps, positive
displacement transfer pumps, VFD-controlled motors)
Inspect O&M Data
Recommendations:
• Site-specific O&M forms or use real-
time data acquisition
• Dedicated O&M technicians and
optimization engineers
• O&M data to evaluate:
> system pressures and flow rates
> concentration data
> pump cycling
> treatment system retention time
Determine the degree of system effectiveness
Determine if design goals are met. Examples:
• Are SVE wells providing an effective ROI?
• Can groundwater pumps be lowered or the flow rate increased?
• Are pumping wells providing adequate capture?
• Can different equipment be used?
• Can increased vacuum levels enhance groundwater capture?
Compare the actual concentration reductions versus predicted
concentration reductions.
RW-1 Groundwater Concentrations
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
Jun-00 Oct-00 Jan-01 Apr-01 Jul-01 Nov-01 Feb-02 May-02
Date
Gro
un
dw
ate
r C
on
ce
ntr
atio
n (
pp
b)
BTEX (ppb)
MTBE (ppb)
Determine the degree of system effectiveness
Information to evaluate includes:
• Concentrations over time
• Treatment equipment removal efficiencies
• Compare actual concentrations to predicted.
BTEX Removal Efficiency
85.00
90.00
95.00
100.00
15-Jul-02 25-Jul-02 4-Aug-02 14-Aug-02
Date
Re
mo
va
l E
ffic
ien
cy (
%)
Actual Removal Efficiency (%)
Review Mass Recovery, Contaminant Reduction, O&M Costs
VAPOR-PHASE CONCENTRATION DATA AND MASS REMOVAL
0
2,000
4,000
6,000
8,000
1-Apr 29-Aug 26-Jan 25-Jun 22-Nov 20-Apr 17-Sep
DATE
VA
PO
R-P
HA
SE
>C
4-C
10 H
C
CO
NC
(P
PM
V)
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
TO
TA
L P
OU
ND
S
OF
VA
PO
R-
PH
AS
E C
4-C
10
HC
RE
CO
VE
RE
D
vapor-phase >C4-C10 HC conc (ppmv)
pounds of vapor-phase >C4-C10 HC
• Do increasing mass recovery trends occur following system adjustments?
• Has the technology reached it’s endpoint?
• Are other technologies available?
• What is the mass recovery in each phase?(adsorbed, dissolved, separate)
Separate-Phase Product Recovery Over Time
0
200
400
600
800
1000
1200
30-Mar
30-May
30-Jul
30-Sep
30-Nov
30-Jan
30-Mar
30-May
30-Jul
30-Sep
30-Nov
30-Jan
Date
Cum
ula
tive S
epara
te-P
hase P
roduct R
ecovere
d
(gallo
ns)
• Compare dissolved concentrations over time
• Estimate contaminant mass during remediation to determine contaminant reduction and mass remaining
Well ID
Dissolved Concentrations
Pre-RemediationFollowing 12 months of
Remediation
Benzene (ppb)Total BTEX
(ppb)
MTBE
(ppb)Benzene (ppb)
Total
BTEX
(ppb)
MTBE
(ppb)
OW-1* 860 4,490 110 ND ND ND
OW-2* 13,000 60,300 5,500 ND ND 25
RW-1 5,200 6,650 14,000 6 6 89
RW-2* 13,000 20,800 16,000 ND ND ND
RW-3* 4 9 7 ND ND ND
Mass RecoveryPre-
remediation
Following 12 months
of remediation
Dissolved
Phase MassBTEX (lb)
24.80 0.02
Adsorbed-
Phase Mass
BTEX (lb) 826.70 0.70
TPH (lb) 3,240.0 9.33
Adsorbed-Phase BTEX Mass % Decrease 99.92%
Review Mass Recovery, Contaminant Reduction, O&M Costs
BTEX
(μg/l)
5
500
1,000
2,000
4,000
8,000
12,000
16,000
20,000
Before
Remediation
BTEX
(μg/l)
5
500
1,000
2,000
4,000
8,000
12,000
16,000
20,000
After 16
Months of
Remediation
Visual Comparison of Dissolved Concentrations
OPERATING COST PER POUND OF HYDROCARBONS
RECOVERED
$-
$100
$200
$300
$400
$500
Ap
r
May
Ju
n
Ju
l
Au
g
Sep
Oct
No
v
Dec
Jan
Feb
Mar
Ap
r
May
Ju
n
Ju
l
Au
g
Sep
Month
Opera
ting C
ost
Per
LB
of
Hydro
carb
ons
Recovere
d• Determine operating cost / pound of contaminant recovered
• Data should show frequent fluctuations as efficiencies are realized
Review Mass Recovery, Contaminant Reduction, O&M Costs
Evaluate System Up-time and Down-time
• System shut-downs should be evaluated to determine cause of shut-
down
• Shut-downs should be addressed immediately to maximize system
operation and up-time
• Telemetry units and remote monitoring controls can be used to alert
of a system shut-down (via phone, fax, e-mail)
Identify capital costs for upgrades and modifications
• Upgrades/modifications that improve system operation include
> add more extraction/injection wells
> upgrade existing equipment
> install more efficient wells / develop existing wells
> reduce pipe headloss
> change recovery or treatment technologies
Ways to evaluate and justify the need for system
upgrades/modifications
• Perform life-cycle cost analyses
• Conduct additional site characterization activities
• Perform additional remedial feasibility tests
• Use modeling applications or predictive tools
Why is Remote Monitoring Helpful?
• Decreases response time if problem arises
• Can identify problems prior to shutdown
• Increases system up-time
• Decreases # site visits required
• Data logging provides accurate tabular data -decreases reporting
time
• Analysis of logged data enables one to troubleshoot complex
system problems
• Added health & safety control
Remote Monitoring Systems
Data
Processing
Local
Monitor
Panel
Monitor
Analog
Inst.
Digital
Switches
Local Data
Storage Computer Data
Storage
Web Server
Data Storage
• Liquid level transducers installed to measure drawdown.
• Flow transducers measure groundwater recovery rate from each trench/well.
• Electrical submersible pumps controlled automatically via VFDs.
• Adjust flow rates via VFDs/valves to achieve optimal drawdown.
Remote Monitoring - Examples
Remote Monitoring Computer Interface
Remote Monitoring Computer Interface
Soil Vapor ExtractionIdeas for Optimization
• Review system and individual well vacuum levels, mass recovery,
and flow rates
• Analyze which wells to use and
vacuum levels to operate
• Analyze screen interval versus
DTW and applied vacuum
• Evaluate system vacuum losses
Example SVE Data and Review
SVE Well flow vacuum mass recovery
RW-1: 40 scfm 10 iw 15.7 lb/day
MW-4: 28 scfm 45 iw 32.0 lb/day
RW-2: 60 scfm 3 iw < 2.0 lb/day
MW-10 1 scfm 45 iw < 2.0 lb/day
MW-11 60 scfm 8 iw 45.0 lb/day
SVE blower can do 200 scfm @ 50 iw
Low mass recovery
RW-2: High flow, low vac, and low mass recovery – broken line?
MW -10: Low flow, high vac, and low mass recovery – water or clog in line?
Turn off SVE wells with low mass recovery to focus on high-mass SVE wells!!!!
Example SVE Data and Review
SVE Well flow vacuum mass recovery
RW-1: 40 scfm 10 iw 15.7 lb/day
MW-4: 28 scfm 45 iw 32.0 lb/day
RW-2: 60 scfm 3 iw < 2.0 lb/day
MW-10 1 scfm 45 iw < 2.0 lb/day
MW-11 60 scfm 8 iw 45.0 lb/day
SVE blower can do 200 scfm @ 50 iw
Low mass recovery
RW-2: High flow, low vac, and low mass recovery – broken line?
MW -10: Low flow, high vac, and low mass recovery – water or clog in line?
Turn off SVE wells with low mass recovery to focus on high-mass SVE wells!!!!
Automated SVE Optimization
In-Line PID
(Cycles to each leg)
Vacuum Transducer
Flow Transducer
Processes
Data
SmartVAC
SVE
System
System Controls/
PLC
^ ^ ^
O O O
Adjusts valves to change
vacuum/ flow from each well
X X X
1 2 3
Automated SVE Optimization
Groundwater Recovery & TreatmentIdeas for Optimization
• Track pressure drops and concentrations through
system equipment over time
• Evaluate drawdown via hydrographs – compare
drawdown to pump intake level (potential to
adjust lower / raise pumps)
• Evaluate retention time through system
• Check all pumps/equipment/wells for fouling and
proper operation
Total-Phase Vacuum ExtractionIdeas for Optimization
• Evaluate well and straw vacuum levels and ensure there is not significant vacuum loss
• Compare recovered flow rates (vapor and gw) from system versus pilot test data
• Ensure LRP is not operating at a vacuum level that could be too high or too low for the pump
• Periodically perform individual well extraction tests during O&M (compare vapor/gw flow, PID, vacuum)
Air SpargingIdeas for Optimization
• Obtain flow/pressure data at each
point (can change on a daily basis
and should be re-adjusted)
• System cycling preferred – use
O&M data to determine cycling
durations/frequencies
• Obtain DO, mounding, pressure
influence data routinely
• Review pressure data at each point
to ensure that AS points are not
silting/fouling
• Check for short-circuiting or high
flow points
Optimization Examples
Example 1 - Former petroleum terminal with gw/product recovery:
• Limited product recovery (270 gal in 2006; 140 gal in 2007).
• Optimization work included cleaning/refurbishing pumps.
• Results: approx. 1,300 gal product recovered in just over 6 months since optimization work performed (> 10x increase in NAPL recovery).
Example 2 - Service station site:
• Vacuum-enhanced groundwater extraction (VEGE system reached asymptotic mass recovery levels in 2006).
• Performed feasibility testing in 2007 using multiple technologies. Air sparging showed positive results.
• Added air sparging equipment to existing system in 2007System deactivated following 5 months of air sparging after clean-up goals achieved.
Other Optimization Ideas: VFDs and Redundant Pumps
• Variable frequency drives
(reduce power load)
• Redundant transfer pumps,
SVE blowers, or other
equipment
Ozone w/ Air & OxygenHydrogen Peroxide
maximum ROI
Groundwater
Flow Direction
Hydrogen Peroxide
Other Optimization Ideas: Ensure Proper ROI – and Enhance ROI as-needed
Product Recovery Enhancement Ideas: Vacuum? Flushing? Surfactants? Ozone?
Gas Movement in a
Recovery Trench
Ozone Injection
Point
Impacted soil going
back to original
appearance
View appearance changes in soil, water, NAPL
GP-11
pre-remediation10’ to 11’ bgs
GP-11B
after 3 weeks
10’ to 11’ bgs
GP-4
pre-remediation
24’ to 26’ bgs
GP-4B
after 3 weeks
24’ to 26’ bgs
View appearance changes in soil, water, NAPL
GP-6
pre-remediation
12’ to 13’ bgs
GP-6B
after 3 weeks
12’ to 13’ bgs
GP-6
pre-remediation
13’ to 14’ bgs
GP-6B
after 3 weeks
13’ to 14’ bgs
View appearance changes in soil, water, NAPL
View appearance and viscosity changes NAPL
Visualize Concentration Data – Pre-Design and During System Operation
Injection Point Locations Selected Following LIF Investigation
Pre-Remediation 3 Weeks Into Remediation Post Remediation (after 8 weeks)
Visualize Concentration Data – During System Operation (Soil Headspace Readings Shown)
2
20
100
300
500
1000
2000
3000
19000GT4
50 100 150 200 250 300 350 400 450
50
100
150
200
250
300
350
BTEX Concentration Reductions
BTEX (ug/L)
After Three Injections
Oct ‘05
GT4
50 100 150 200 250 300 350 400 450
50
100
150
200
250
300
350
Pre-HypeAir
Mar ‘04
Short-Term ISCO: Adjustments and Evaluations Pre and Post Injection Events (BTEX Site in NY)
Pre-Remediation After 2 Injection Events
Short-Term ISCO: Adjustments and Evaluations Pre and Post Injection Events (ETU Remediation Site in FL)
GERMANTOWN PIKE
FORMER EXXON
SERVICE STATION
MW-7
OIL UST
WASTE
VALL
EY
FO
RG
E R
OAD
GRASS
GRASS
MW-2
MW-3
MW-1
RW-2
TANK FIELD
MW-6
MW-4
RW-1
RW-1A
FUEL
OIL TANKMW-5
PUMPS
PUMPS
PLA
NTE
R
SEPTIC
pre-remediation
April 2003
GERMANTOWN PIKE
FORMER EXXON
SERVICE STATION
MW-7
OIL UST
WASTE
VA
LLEY
FO
RG
E R
OA
D
GRASS
GRASS
MW-2
MW-3
MW-1
RW-2
TANK FIELD
MW-6
MW-4
RW-1
RW-1A
FUEL
OIL TANKMW-5
PUMPS
PUMPS
PLA
NTE
R
SEPTIC
September 2003
0
50
100
150
200
250
300300
250
200
150
100
50
20
MTBE (µg/l)
GERMANTOWN PIKE
FORMER EXXON
SERVICE STATION
MW-7
OIL UST
WASTE
VALL
EY F
OR
GE
RO
AD
GRASS
GRASS
MW-2
MW-3
MW-1
RW-2
TANK FIELD
MW-6
MW-4
RW-1
RW-1A
FUEL
OIL TANKMW-5
PUMPS
PUMPS
PLA
NTE
R
SEPTIC
October 2004
MTBE Concentrations vs. Time
0
500
1000
1500
2000
2500
Mar-
03
Aug-
03
Jan-
04
Jun-
04
Nov-
04
Apr-
05
Sep-
05
Feb-
06
MT
BE
(u
g/L
) MW-7
MW-8
MW-12
RW-1A
Dissolved MTBE Concentrations (ug/l)
Short-Term ISCO: Adjustments and Evaluations After Each Injection Event
Dissolved BTEX Concentrations (ug/l)
% Reduced
Since April
2003Well ID 4/03 7/03 8/03 10/03 1/04 4/04 8/04 10/04 10/05
MW-3 312.2 748.1 10.9 76.5 3.5 ND(5) ND(5) ND(5) ND(5) 100%
MW-4 3.6 ND(5) ND(5) 2.5 ND(5) ND(5) ND(5) ND(5) ND(5) 100%
MW-6 793.6 687.4 708.9 302.4 287.9 221.4 201.5 159.3 ND(5) 100%
RW-1A 771.8 87.6 92.9 23.9 284.3 43.5 ND(5) ND(5) ND(5) 100%
RW-1 ND 118.8 47.5 42.9 2.6 47 98 30 ND(5) 100%
AVERAGE 100%
Injection event
Prior to each injection event, the injection plan was modified for optimal injection.
Short-Term ISCO: Adjustments and Evaluations After Each Injection Event
Dissolved Oxygen (9/20/09)Dissolved Oxygen (7/31/09)
Note: The majority of pre-remediation source area DO levels were less than 1.78 mg/l
Dissolved Oxygen Contours During Remediation (9/20/09)
5
10
10
15
20
P
P
23.28
15.7
13.98
11.61
13.45
7.01
15.08
11.93
11.62
14.5
14.75
ISCO: Visualize Performance Data – During System Operation (Oxygen Influence During Ozone Injection Shown)
GRASS
GRASS
ASPHALT
ASPHALT
EDGELY ROAD
MIL
L C
REEK R
OAD
MW-1
MW-3
MONITORING WELL
%%uLEGEND
FORMER
DISPENSER
ISLAND
FORMER
DISPENSER
ISLAND
THREE BAY
GARAGE
BUILDING
FORMER
UST FIELD
MW-5
VAPOR EXTRACTION POINT
INJECTION WELL
SVE-1
IW-1
IW-2
WATER LINE
UNDERGROUND ELECTRIC LINE
UNDERGROUND TELEPHONE LINE
MW-4
MW-2
60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440
40
60
80
100
120
140
160
180
200
220
240
260
280
300
105 feet
4 days after 3rd Event
– 10/10/06
0.1
0.5
1
2
5
10
30
Dissolved
Oxygen (DO)
concentration
(mg/L)
IW-3
IW-4
IW-5
GRASS
GRASS
ASPHALT
ASPHALT
EDGELY ROAD
MIL
L C
REEK R
OAD
MW-1
MW-3
MONITORING WELL
%%uLEGEND
FORMER
DISPENSER
ISLAND
FORMER
DISPENSER
ISLAND
THREE BAY
GARAGE
BUILDING
FORMER
UST FIELD
MW-5
VAPOR EXTRACTION POINT
INJECTION WELL
SVE-1
IW-1
IW-2
WATER LINE
UNDERGROUND ELECTRIC LINE
UNDERGROUND TELEPHONE LINE
MW-4
MW-2
60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440
40
60
80
100
120
140
160
180
200
220
240
260
280
300
80 feet
39 days after 3rd Event
– 11/14/06
IW-4
IW-3
IW-5
Short-Term ISCO: Visualize Performance Data – Post Injection (Oxygen Influence Shown)
August 1, 2009 August 24, 2009Naphthalene
Concentration
µg/L
September 10, 2009 September 20, 2009
ISCO: Visualize Concentration Data For Source Area (Naphthalene Concentrations Shown)
Benzene
Concentration
µg/L
Jan 10, 2010
Post Remediation
Aug 1, 2009
Pre-Remediation
ISCO: Visualize Concentration Data For Entire Site as Well as Source Area (Benzene Concentrations Shown)
5
5
RESIDENTIAL AREA
RESIDENTIAL AREA
RESIDENTIAL AREA
ALLEY
P
P
10.14.63
17.87
1.56
0.311.762.1 3.07
2.92
4.18
1.91
8.05
0.97
0.08
0.110.22
3.470.11
0.2
3.49 0.03
0.44
3.020.64
1.84
0.41
7.5
6.76 0.14
4.2
July 31, 2009 September 20, 2009 January 15, 2010
5
10
15
RESIDENTIAL AREA
RESIDENTIAL AREA
RESIDENTIAL AREA
ALLEY
P
P
23.28
15.713.98
11.6113.45
7.0115.08
11.9311.62
14.5
14.75
5.73
1.39
7.45 0.18
5
5
10
15
RESIDENTIAL AREA
RESIDENTIAL AREA
RESIDENTIAL AREA
ALLEY
P
P10.54
1212.51
1.215.93
0.36
9.82
10.8910.23
3.62
13.92 12.89
0.51
0.86
0.31
1.01
0.9
7.91
3.98
7.72
27.57 0.37
5
10
15
20
25
Dissolved Oxygen
(mg/L)
ISCO: Visualize Influence Data For Entire Site as Well as Source Area (DO Shown)
It’s never too late to re-look at the source or perform a proper feasibility test!
