NIBW SITE OVERVIEW June 14, 2017 2 SITE HISTORY Volatile organic - - PowerPoint PPT Presentation

NIBW SITE OVERVIEW

June 14, 2017

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SITE HISTORY

• Volatile organic compounds (VOCs)

detected in groundwater in 1981

• Placed on National Priorities List

(NPL) in 1983

• 1988 Record of Decision (ROD)

required extraction and treatment of impacted groundwater to meet MCLs in the middle aquifer (MAU) and lower aquifer (LAU)

• 1991 ROD required upper aquifer

(UAU) monitoring and soils investigations/cleanups in selected areas

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• CGTF began treating extracted groundwater in 1994 and providing to

Scottsdale

• Proactive groundwater remedies implemented at three other facilities
• MRTF: northern LAU containment (1997)
• Area 7 and Area 12: MAU source control (1999)
• Amended ROD (2000) and Amended Consent Decree (2002)
• Replaced earlier RODs and CDs
• Documented remediation to include proactive remedial actions
• NIBW Granular Activated Carbon Treatment Facility (NGTF) completed

in 2014 under an Explanation of Significant Differences (ESD)

SITE HISTORY(continued)

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Three Alluvial Aquifer Units

 UAU – Average 150 feet thick  MAU – Average 450 feet thick  LAU – >700 feet thick

HYDROGEOLOGIC UNITS

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WESTERN MARGIN

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Miller Road Treatment Facility

• Began operations in 1997
• Owned and operated by EPCOR
• Wells PV14 and PV15 treated
• Groundwater treatment by air stripping
• Treated groundwater to EPCOR potable

water system

NIBW GAC Treatment Facility

• Completed in 2013, with full operations

in 2014

• PCX-1 currently treated, with potential

to add PG-41

• Granular activated carbon (GAC)

treatment

• Treated groundwater to COS municipal

supply or SRP canal

Area 7 Groundwater Extraction and Treatment System

• Began operation in 1999
• Built by Siemens and
• perated by Motorola
• Ultraviolet oxidation and air

stripping treatment

• Treated groundwater

recharged to UAU aquifer

Central Groundwater Treatment Facility

• Began operation in 1994
• Owned and operated by City of Scottsdale
• Groundwater treated by air stripping
• Treated groundwater to Scottsdale municipal

supply

Area 12 Groundwater Extraction and Treatment System

• Began operation in 1999
• Owned and operated by Motorola Solutions
• Groundwater treated by air stripping
• Treated water to SRP irrigation canal system

TREATMENT FACILITIES

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2016 Pumping

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UAU TCE

Oct 2001 – Oct 2016

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VOC Mass Flux in UAU

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MAU TCE

Oct 2001 – Oct 2016

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LAU TCE

Oct 2001 – Oct 2016

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NIBW TCE October 2016 Groundwater Plumes

SUMMARY O OF 2016 2016 GRO ROUNDWATE TER EX R EXTR TRACTI TION & & TREA TREATM TMENT

Treatment System Extraction Well TCE Mass Removal (in pounds) Annual Pumpage (in acre-feet) Annual Pumpage (in gpm) CGTF COS-31 35 1,142 708 COS-71A 130 1,718 1,065 COS-72 36 1,168 724 COS-75A 393 2,866 1,777 TOTAL 594 6,894 4,274 MRTF PV-14 9 3,277 2,032 PV-15 33 1,904 1,180 TOTAL 42 5,181 3,212 NGTF PCX-1 - TOTAL 561 3,664 2,272 Area 7 7EX-3aMA 136 155 96 7EX-4MA 184 51 32 7EX-6MA 401 236 146 TOTAL 720 442 274 Area 12 MEX-1MA 105 871 540 SRP 23.6E6N 344 1070 664 TOTAL 449 1,941 1,203 OVERALL 2,367 18,123 11,235

NIBW METRICS

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SITE 1994 (lbs) 1995 (lbs) 1996 (lbs) 1997 (lbs) 1998 (lbs) 1999 (lbs) 2000 (lbs) 2001 (lbs) 2002 (lbs) 2003 (lbs) 2004 (lbs) 2005 (lbs) 2006 (lbs) 2007 (lbs) 2008 (lbs) 2009 (lbs) 2010 (lbs) 2011 (lbs) 2012 (lbs) 2013 (lbs) 2014 (lbs) 2015 (lbs) 2016 (lbs) Inception To Date (pounds) CGTF 1,397 1,432 5,535 4,493 4,935 4,858 4,007 3,756 2,795 3,096 2,146 2,013 2,201 1,172 1,476 1,512 1,215 1,054 1,032 1,004 626 525 594

52,874

MRTF 130 168 281 298 573 621 587 628 667 545 524 620 678 592 624 401 73 67 42

8,119

NGTF 264 240 595 561

1,661

AREA 7 704 2,384 1,749 1,105 1,922 1,552 1,018 1,030 987 669 802 901 840 1,001 843 762 726 720

19,714

AREA 12 550 940 406 610 317 301 217 328 215 269 249 220 214 181 198 340 414 449

6,418

TOTALS

1,397 1,432 5,535 4,493 5,065 6,280 7,612 6,209 5,083 5,956 4,586 3,876 4,226 2,919 2,938 3,182 3,014 2,700 2,838 2,712 2,041 2,327 2,366

88,786

TCE MASS REMOVED

SITE 1994 (MG) 1995 (MG) 1996 (MG) 1997 (MG) 1998 (MG) 1999 (MG) 2000 (MG) 2001 (MG) 2002 (MG) 2003 (MG) 2004 (MG) 2005 (MG) 2006 (MG) 2007 (MG) 2008 (MG) 2009 (MG) 2010 (MG) 2011 (MG) 2012 (MG) 2013 (MG) 2014 (MG) 2015 (MG) 2016 (MG) Inception To Date (MG) CGTF 2,307 1,051 4,053 3,657 3,419 3,436 3,197 3,575 3,170 3,286 3,094 3,175 3,228 1,823 2,502 2,698 2,338 2,697 2,190 1,905 1,559 1,776 2,246

62,384

MRTF 744 1,507 1,504 2,091 1,521 1,994 2,050 2,086 2,063 2,156 1,265 1,275 1,876 2,455 2,799 2,925 2,104 2,110 2,104 1,688

38,317

NGTF 425 479 1,076 1,194

3,174

AREA 7 26 145 142 144 221 216 212 212 208 169 192 185 182 168 134 121 129 144

2,950

AREA 12 139 544 536 456 300 359 369 486 382 504 474 478 479 343 396 419 506 633

7,803

TOTALS

2,307 1,051 4,053 4,401 4,926 5,105 5,977 5,774 5,764 5,857 5,755 5,819 6,082 3,678 4,450 5,239 5,455 6,157 5,627 4,964 4,688 5,592 5,905

114,627

GROUNDWATER PUMPED

SITE 1994 (ug/L) 1995 (ug/L) 1996 (ug/L) 1997 (ug/L) 1998 (ug/L) 1999 (ug/L) 2000 (ug/L) 2001 (ug/L) 2002 (ug/L) 2003 (ug/L) 2004 (ug/L) 2005 (ug/L) 2006 (ug/L) 2007 (ug/L) 2008 (ug/L) 2009 (ug/L) 2010 (ug/L) 2011 (ug/L) 2012 (ug/L) 2013 (ug/L) 2014 (ug/L) 2015 (ug/L) 2016 (ug/L) Inception To Date (ug/L) CGTF 71 160 160 144 169 166 147 123 103 110 81 74 80 75 69 66 61 46 55 62 47 35 31

99

MRTF 10 13 16 23 34 35 33 36 36 50 48 39 32 25 25 22 4 4 3

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NGTF 73 59 65 55

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AREA 7 3,172 1,926 1,443 899 1,019 842 562 569 556 464 489 571 542 696 737 738 660 585

783

AREA 12 464 202 89 157 124 98 69 79 66 63 62 54 52 62 59 95 96 83

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TOTALS

71 160 160 120 120 144 149 126 103 119 93 78 81 93 77 71 65 51 59 64 51 49 47

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AVERAGE TCE CONCENTRATIONS

• All vadose (soils) zone remediation programs completed; no remaining

threat to groundwater

• Area 7 – About 7,000 lbs TCE removed
• Area 8 – About 650 lbs TCE removed
• Area 12 – About 950 lbs TCE removed
• About 9,000 pounds removed from soils
• All components of the groundwater pump-and-treat remediation

program are functioning properly (CGTF, MRTF, NGTF, Area 7, and Area 12)

• Over 88,000 pounds of TCE removed from groundwater
• 2016 Five Year Review found groundwater remedy protective
• Formal site protectiveness statement deferred to evaluate potential risk of

vapor intrusion and treatment system impacts to ambient air

• Vapor intrusion assessment investigations underway

SITE STATUS

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Low er Alluvium Unit Plume

October 1990 October 1991 October 1992 October 1993 October 1994 October 1995 October 1996 October 1997 October 1998 October 1999 October 2000 October 2001 October 2002 October 2003 October 2004 October 2005 October 2006 October 2007 October 2009 October 2010 October 2011 October 2012 October 2013

> 100 µg/L

TCE Concentrations

5 – 50 µg/L 51 – 100 µg/L

October 2014 October 2008 October 2015 October 2016

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Questions? Thank you!

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EXTRA SLIDES

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VAPOR INTRUSION INVESTSIGATIONS

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• 7 historical source

Areas investigated based on 2016 5YR recommendation

• 45 Soil Gas Sampling

Points installed and sampled

• 6 out of 7 Areas had

soil gas concentrations below screening levels

• Indoor air sampling

conducted at Area 7

• Isolated detections

above screening levels in two buildings

OUI RI 1984- 1986

Site History Timeline

Early Site Activities Original RODs & CDs Required & Voluntary Programs Remedial Activities AROD and ACD 2011 & 2016 5YR

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OU I FS OUI ROD OUI CD 1992

1980 1985 1990 1995 2000 2005 2010 2015 2020

OUII ROD 1991 AROD 2001 VOC Detection in GW 1981 NCP List 1983 1988 PV Agreement re: N. LAU 1994 MRTF 1997 Area 7 and Area 12 1999 FSA 1999 OUII CD 1993 ACD 2003 GMEP 2002 Construction Complete 2006 ESD 2012 5YR 2011 5YR 2016 NGTF 2013 CGTF 1994

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