7th street and arizona avenue wqarf site community advisory board meeting february...

7th Street and Arizona Avenue WQARF SiteCommunity Advisory Board Meeting

February 27, 2018

7th Street and Arizona Avenue WQARF Site Project Update: 4th

Quarter 2017 Groundwater Monitoring, Early Response Action & Goals for Fiscal Year 2018

WQARF PROCESS OVERVIEW

4th Quarter 2017 Groundwater Monitoring

Groundwater Elevation -Perched Aquifer Measured water levels

from 43 monitoring wells (MWs)

Light non-aqueous phase liquid (LNAPL) observed in 10 MWs (~0.01 to 7.43 feet [ft] thick)

General flow to northwest

PERCHED AQUIFER


Groundwater Elevation–Regional Aquifer Measured water levels

from 4 MWs. General flow to northwest

REGIONAL AQUIFER


Water Quality Sampled 32 wells

– 20 Perched MWs w/o LNAPL– 8 Perched MWs w LNAPL– 4 Regional MWs

Perched w/o LNAPL: Tetrachloroethene (PCE) in groundwater in 7 MWs from 2.2 to 1,300 micrograms per liter (ug/l)

Perched w/ LNAPL: PCE in LNAPL in 2 MWs from 64,000 to 81,000 ug/l

Regional: PCE in groundwater in 1 MW 0.74 to 7.3 ug/l

PERCHED AQUIFER


PERCHED AQUIFER

Water Quality PCE plume smaller in size

since 2013 Highest PCE dissolved in

LNAPL (64,000 to 81,000 ug/l)

Next highest under 847 N. Stone Ave (1,300 ug/L)

PCE in regional aquifer at 7AZR-3 from 0.74 to 7.3 ug/l

Early Response Action – Soil Vapor Extraction (SVE)

Soil Vapor Extraction (SVE) System Construction Installed 4 triple nested wells Completed ~200 ft. of trenching

and lateral well connection to SVE system

Sited, plumbed and powered blower/motor package

Sited and plumbed 2 granular activated carbon vessels

Early Response Action - SVE wells being drilled (low-clearance rig)

Early Response Action – Completed SVE wells

Early Response Action – Trenching for well connection to system

Early Response Action – SVE well manifold

Early Response Action – Blower/motor package

Early Response Action – Granular activated carbon

Early Response Action – Completed system

Looking SE

Looking NE

Early Response Action - SVE operation

Operation Summary System startup on Dec 5th, 2017 Approximately 832 lbs. of PCE cleaned up as of Feb 21, 2018

0

100

200

300

400

500

600

700

800

900

Cumulative PCE Mass Removed (lbs)

Cum

ulat

ive

PCE

(lbs)

Date

Remaining Goals For Fiscal Year 2018

Continue SVE operation Install one regional and one perched aquifer monitoring

well down gradient of 847 N. Stone Ave source

Early Response Action - SVE operation

QUESTIONS?

Park – Euclid WQARF SiteCommunity Advisory Board MeetingFebruary 27, 2018

Feasibility Study Update

• Draft Feasibility Study Report submitted on April 28, 2016

• No comments received during 30-day public commentperiod

• Comments from ADEQ received on December 15, 2016and February 27, 2017

• Final Feasibility Study Report submitted on October 18,2017

• Final Approval from ADEQ received on November 14,2017

Park – Euclid Status Update Page 2

Site Conceptual Model


Feasibility Study Proposed Remedy

• Upper Vadose Zone: Monitored Natural Attenuation untilYear 15

• Perched Aquifer: Monitored Natural Attenuation for 30years

• Lower Vadose Zone: Continuous soil vapor extraction for 5years with expanded monitoring until Year 25

• Regional Aquifer: Pumping with a single extraction well at50 gallons per minute with granular activated carbontreatment prior to reinjecting to the RA for 30 years,followed by monitoring until Year 35.


Site Conditions Update


Perched Aquifer Diesel Product


Site Conditions Update (continued)

Perched Aquifer Vinyl Chloride in Groundwater


Site Conditions Update (continued)

Regional Aquifer PCE in Groundwater


Remedial Design Refinement

Perched Aquifer - Five new monitoring wells for plumerefinement and downgradient extent

Remedial Design Refinement (continued)


Lower Vadose Zone – Four vapor monitoring well clusters to evaluatevertical and horizontal extent and for SVE system performance monitoring


Remedial Design Refinement (continued)

Regional Aquifer – Three monitoring wells for deep plume extent

Lower Vadose Zone Early Response Action


Lower Vadose Zone Early Response Action (continued)


– PCE concentrations in extracted vapor decreased throughout operation– Gasoline range Fuel Hydrocarbons increased/remained stable

Lower Vadose Zone Early Response Action (continued)

• Rationale for Restarting the SVE System now– Groundwater elevations increasing and may saturate contaminated

intervals making it more difficult and expensive to clean up later– PCE concentrations were still declining at shutdown– Rebounding PCE and TCE concentrations in vapor extraction well– Increasing dissolved PCE and TCE in groundwater during rebound

monitoring

• Change vapor treatment from GAC to Catalytic Oxidizer

• Operate as ERA for up to 3 years.


Proposed Remedial Action Plan


• PRAP development to begin after remedial designrefinement

• PRAP document to include– Boundaries of the site subject to remedial action– Results of remedial investigation and feasibility study– The proposed remedy and its estimated costs– How remediation goals and selection factors in § 49-282.06 have

been considered

• As part of the PRAP, a 60 percent design of the remedywill be completed to support the cost estimate.

Major Task Schedule

• Access Agreements (11/15/17 – 3/14/18)

• Remedial Design Refinement (2/1/18 - 8/1/18)

• Prepare and Issue PRAP (6/21/18 – 1/30/19)

• Catalytic Oxidizer Design and Permitting (2/15/18 – 9/22/18)

• CatOx Equipment Procurement and Installation (9/24/18 - 12/14/18)

• SVE/CatOx Operation, Maintenance, and Monitoring (12/14/18 –12/27/19)

• Long Term Monitoring (ongoing semi-annual/annual monitoring andreporting)


www.aecom.com

Stone Avenue and Grant Road WQARF Site

February 27, 2018 CAB MeetingWilliam Ellett, Associate Hydrogeologist/Project Manager

Stone and Grant WQARF Site Location

Nash Elementary

Site History

Former dry cleaner operated from 1946 to mid 1970’s.

Automotive Paint Specialists took over the building in mid 1070’s.

Building is currently occupied by Finishmaster, Inc.

Leaking Underground Storage Tank (LUST) gasoline release on north side of Grant Rd.

The City of Tucson completed a Phase I Environmental Assessment and sub-slab soil-gas sampling in 2014.

Site History continued

Site History continued

ADEQ completed Preliminary Investigation in February 2016.

Proposed for WQARF listing in May 2016.

Listed on WQARF Registry in January 2017.

Began Early Response Action (ERA) in April 2017 with Geosyntec Consultants.

Completed Community Involvement Plan and began Remedial Investigation in August 2017 with Clear Creek Associates.

ERA Shallow Soil-Gas Survey

ERA Angled Soil-gas Profile and SVE Well

ERA/SVE System Layout

Completed SVE System

SVE System Mass Removal

Remedial Investigation – Regional GW Wells

SG-2

SG-1

SG-4

SG-3

Drilling a Monitoring Well at Stone & Grant

Surface Completion for New Well

Shallow Soil-Gas Survey at Former Home Laundry and Dry Cleaning

Northwest of Finishmasters in Grant-Stone shopping center.

Investigated to see if there was an additional source of contamination for the Stone and Grant WQARF site.

Collected four shallow soil-gas samples outside former dry cleaner suite.

Results indicated a possible vapor intrusion issue for TCE and PCE.

Indoor air samples were taken that showed no TCE and PCE only slightly above residential screening level.

Plan to take indoor samples again in June to show any seasonal variation.

Site looks like it is separate from Stone and Grant Site, so it is now a new Preliminary Investigation site.

Future Plans

Conduct a thorough evaluation of data from the LUST site and all data collected so far for the Remedial Investigation by March 31.

Collect soil-gas data from shallow GW wells.

Collect any other data needed to fill data gaps.

Write draft Remedial Investigation by June 30 if possible.

Proceed to Feasibility Study.

QUESTIONS?

William Ellett

(520) 628-6714

[email protected]

7th street and arizona avenue wqarf site community advisory board meeting february...

Documents