ExxonMobil RI0001333 Permit: Stormwater Discharge Regulations, Slides of Ballistic and Cruise Missile Technology

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RHODE ISLAND

DEPARTMENT OF ENVIRONMENTAL MANAGEMENT

OFFICE OF WATER RESOURCES

235 Promenade Street, Providence, Rhode Island 02908

October 2, 2020

CERTIFIED MAIL

Ms. Amy Weinberger, Terminal Superintendent

ExxonMobil Oil Corporation - East Providence Terminal

1001 Wampanoag Trail

East Providence, RI 02915

RE: ExxonMobil Pipeline Company Public Notice of Draft RIPDES Permit No. RI

Dear Ms. Weinberger:

In accordance with regulations adopted pursuant to Chapter 46-12 of the General Laws of Rhode Island the

Rhode Island Department of Environmental Management (DEM) public noticed the reissuance of the

Rhode Island Pollutant Discharge Elimination System (RIPDES) Permit for storm water, groundwater

infiltration/inflow, hydrostatic test water, treated effluent from the PCS groundwater treatment system,

treated effluent from the Tank 52/58 treatment system, treated effluent from the Vanity Fair Cliffs Area

Recovery treatment system, treated effluent from the Silver Springs Golf Course - Vanity Fair Area

Engineered Natural System (ENS), and any allowable non-storm water discharges from the ExxonMobil

Pipeline Company (ExxonMobil) East Providence Terminal on October 2, 2020. Enclosed with this Jetter

is the final draft RIPDES permit and associated public notice for the above-mentioned facility. This

correspondence is in response to the letter dated March 6, 2020 submitted by Amy Weinberger of

ExxonMobil in regard to the 14-day draft permit for the discharges associated with the bulk petroleum

storage terminal located at l 001 Wampanoag Trail in East Providence RI. The following items outline the

DEM' s specific responses to the comments from the March 6th^ letter:

COMMENT NO. 1: In regard to Part I.A.2, ExxonMobil has stated the following information:

1. ExxonMobil proposed to change the discharge from the ENS in the Silver Springs Golf Course - Vanity

Fair Area from and external outfall (originally proposed as Outfall 002A) to an internal outfall (newly

proposed as Outfall 600A) that will discharge to the Providence River via existing Outfall 00!A.

2. To maintain consistency with the other treatment systems discharging to the Providence River (PCS

groundwater treatment system - Outfall 100A, the Tank 52/58 treatment system - Outfall 200A, and

the Vanity Fair Cliffs Area Recovery treatment system -Outfall 300A), ExxonMobil proposed revising

the effluent limitations for the ENS to the proposed effluent limits for Outfalls 100A, 200A, and 300A

contained in the February 5, 2020 draft permit (14 Day Draft) for Benzene, Toluene, Ethylbenzene,

Total Xylenes, Total BTEX, MTBE, Naphthalene, and Total Iron.

3. ExxonMobil requests omission ofTSS from effluent limits and monitoring requirements for the ENS

outfall 600A, which ultimately will discharge through Outfall 001A, as Outfall 001A is monitored for

TSS at a frequency of twice per month.

4. ExxonMobil requests the maximum daily discharge flow rate for the ENS to be increased to 70 gpm to

accommodate seasonal conditions. When in operation, the contingency system has the ability to

discharge at a rate up to 70 gpm, and due to the configuration of the effluent structure of the CTW,

discharge flow rates greater than 14 gpm may be possible. The increased flow limit would allow for

Office of Water Resources/Telephone: 401.222.4 700/Fax: 401.222.

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more efficiently operation of the contingency system and allow for increased flow once the CTW has

reached full maturation.

5. If the RIPDES Program determines that an effluent limit for Total Lead is required for proposed Outfall

600A, ExxonMobil proposes adopting an average monthly limit of 76.2 ug/L, and a maximum daily

limit of 1,987 ug/L, which are based on water quality based calculations utilized for the site and Section

1.26 of the R.J. Water Quality Regulations (250-RICR-150-05-01). These limits reflect a I 0: I dilution

factor, which is the maximum dilution allowed for groundwater remediation projects per DEM policy,

and which is currently applied to internal discharges through Outfall 00IA.

6. In the event that temporary discharge through the existing outfall configuration is required (i.e.,

discharge to the ephemeral features and drainage ditch/unnamed tributary to the Providence River),

ExxonMobil requests that DEM consider the following items when considering effluent limits and that

until such time that the ENS discharge is reconfigured to discharge through Outfall 00 I A, the discharge

location of the ENS be considered the Providence River and not a freshwater Class B surface water as

indicated in the February 2020 draft permit:

a. Based on US EPA's Navigable Waters Protection Rule, revised on January 23, 2020, the nature

of the ephemeral features and drainage ditch into which the ENS discharges precludes their

classification as "waters of the United States." According to the revised Rule, waters/features

are not jurisdictional under the Rule include but are not limited to: groundwater, including

groundwater drained through subsurface drainage systems, such as drains in agricultural lands;

and ephemeral features, including ephemeral streams, swales, gullies, rills and pools. Based

on ExxonMobil's understanding of the nature of groundwater and storm water flow in the

Silver Springs Golf Course area, the discharge location of the ENS is fed from sources that fit

both of the descriptions above. Groundwater has been observed in subsurface drainage systems

present on the golf course that include a subsurface culvert and /or clay pipe that conveys

groundwater and storm water fro north-to-south on the golf course and discharges to a drainage

ditch just south oflndustrial Court on the Terminal.

b. Based on review of historic documents and recent inspections along the area down gradient

from the current Outfall 002A, the receiving area and features appear to be drainage ditches

and/or culverts associated with improvements over the years to control storm water runoff from

the neighboring paved roadways (Fuller Ave, Industrial Ct, and Pawtucket Ave) and industrial

facilities located along Industrial Court.

c. Previous classification of this feature by DEM was included in the DEM letter dated December

12, 1996 (Re: Vanity Fair Area Summary Assessment Report, Paragraph 6, Part B), which

stated that waters hydrologically connected by surface waters to a currently classified water

body is the same classification at that water body. Therefore, the surface water classification

of the North Woods Stream and the Golf Course Stream is the same as the Providence River,

which is SC.

RESPONSE NO. 1:

I. Although the unnamed tributary meets the definition of a "Water of the State" from the Rhode Island

Water Quality Regulations, DEM was notified in an August 24, 2020 email from ExxonMobil that the

discharge of the treated effluent from the ENS was rerouted from discharging to the unnamed tributary

to the Providence River to discharging into the final treatment lagoons that ultimately discharge to the

Providence River. Therefore, since there will no longer be a discharge from the ENS system to the

unnamed tributary, the monitoring requirements for outfall 002A originally contained in Part J.A.2 of

the February 5, 2020 draft permit have been removed from the public notice draft permit. Instead, since

the discharge will be to the final treatment lagoons, DEM added effluent limits and monitoring

requirements for an internal waste stream noted as Outfall 600A to Part I.A. IO of the draft permit. This

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outfall contains the same pollutants to be monitored for as Outfall 002A, which includes Flow, Benzene,

Toluene, Ethylbenzene, Total Xylenes, Total BTEX, MTBE, Naphthalene, Total Iron, and Total Lead.

Also, the Fact Sheet has been revised to remove any references to Outfall 002A and the discharge to

the unnamed tributary to the Providence River and to include the reconfiguration of the ENS discharge

as internal Outfall 600A.

2. Since the treated effluent from the ENS will ultimately discharge to the Providence River, a Class SB

saltwater receiving water body, the monthly average and daily maximum effluent limits for all

parameters ( except Total Lead) for Outfall 600A were changed to the limits proposed for Outfalls I 00A,

200A, and 300A. The manner in which these limits were determined is described in Part IV (Permit

Basis and Explanation of Effluent Limitation Derivation) of the draft permit's Fact Sheet.

3. Similar to the monitoring requirements for Outfalls I00A, 200A, and 300A, TSS monitoring was

removed from the requirements for Outfall 600A as TSS monitoring is required following final

equalization in the treatment lagoons prior to discharge to the Providence River through Outfall 00 IA.

4. Based on ExxonMobil's request, the maximum daily discharge flow rate for the ENS for Outfall 600A

has been increased from 14 gpm to 70 gpm to allow for more efficient operation of the contingency

treatment system and to allow for higher flow rates following the full maturation of the constructed

treatment wetland (CTW) cells. Any increased flow rates of the ENS will be equalized by the two

treatment lagoons preceding Outfall 00 IA, whose flow to the Providence River is controlled via a weir

at the second lagoon.

5. Effluent limits for Total Lead were adopted from the 2019 RIPDES Remediation General Permit for

the discharge category for petroleum sites containing other pollutants discharging to a Class SA or SB

receiving water. The draft permit includes a monthly average limit of 68.1 ug/L and a maximum daily

limit of 1,600 ug/L for Total Lead for the proposed Outfall 600A. The manner in which these limits

were determined is described in Part IV (Permit Basis and Explanation of Effluent Limitation

Derivation) of the draft permit's Fact Sheet.

6. Since the discharge from the ENS has been reconfigured to discharge through Outfall 001A as indicated

in ExxonMobil's August 24, 2020 email, there is no need to include monitoring requirements to the

unnamed tributary to the Providence River. Therefore, the monitoring requirements originally

contained in Part l.A.2 from the February 5, 2020 draft permit have been removed from the public

notice draft permit as noted in the Response 1 above.

COMMENT NO. 2: In regard to Part 1.A.2 Footnote 1, ExxonMobil has stated that the ENS is designed

as a gravity fed passive system with a continuous flow for a flow rate of less than 14 gpm, as expected

during dry weather conditions. Due to this ExxonMobil proposed the following revision to Footnote l:

Footnote 1 to read as follows: "Monitor flow and submit a flow log with the monitoring results. The flow

log shall include the volume, rate and duration of flow generated from the ENS."

RESPONSE NO. 2: The DEM concurs with the suggested revision to Footnote I and has incorporated

the change into the Footnote for Outfall 600A in Part LA.10 of the draft permit.

COMMENT NO. 3: In regards to Part LA.2 -Description of Effluent Sample Location, ExxonMobil has

stated that in order to reflect the potential discharge through the contingency treatment system in the case

that effluent limits are not met in the ENS' s effluent control structure, ExxonMobil proposed the following

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revision to the effluent sample location for this outfall:

Description of Effluent Sample Location to read as follows: "Samples taken in compliance with the

monitoring requirements specified above shall be taken at the following locations: Effluent Control

Structure from the Engineered Natural System (ENS) treatment system, or the contingency treatment

system effluent, when the contingency treatment system is operating."

RESPONSE NO. 3: The DEM concurs with the suggested changes to the description of the sample

location for the ENS and has incorporated the changes into Part I.A. IO of the draft permit.

COMMENT NO. 4: In regards to Parts I.A.2, l.A.3 and I.A.7, ExxonMobil has stated that in order to

provide for operational flexibility, adhere to permitted effluent limits, and since there are multiple test

methods that can return Naphthalene results at or below the MDL specified in the List of Toxic Pollutants,

ExxonMobil proposed to remove the requirement to test Naphthalene using Method 624.

RESPONSE NO. 4: The DEM concurs with ExxonMobil's request above and has removed the footnote

from the above parts of the draft permit that required testing for Naphthalene using EPA Method 624.

ExxonMobil is reminded that all testing required by the permit shall be done using methods listed in 40

CFR 136, unless specifically approved by DEM.

COMMENT NO. 5: In regard to Part I.A.11.a, ExxonMobil has proposed to remove the pH range

limitation, given that pH is not a parameter required to be monitored for in Parts I.A. I -10.

RESPONSE NO. 5: The draft permit does not require ExxonMobil to sample and analyze any of the

discharges authorized by the permit for pH. Part I.A.] I .a of the draft permit contains the acceptable pH

range to support the surface water use classifications as described in the R.l. Water Quality Regulations for

a Class SB water body and was determined to be site-specific for ExxonMobil as described in the

Explanation of Effluent Limitation Derivation/ Water Quality Based Limits section of the Fact Sheet. This

is a narrative effluent limitation only, the numeric effluent limits contained in the previous issuance of this

permit have been removed for Outfall 001 to be consistent with the monitoring strategy for similar industrial

storm water permits. As a result of the above discussion, no changes were made to the draft permit.

COMMENT NO. 6: In regard to Part l.A.27.b, ExxonMobil has proposed the following revision:

Part I.A.27.b to read as follows: "The permitee shall treat shallow groundwater, surface water, and storm

water in the Silver Spring Golf Course area of the Vanity Fair Area with a treatment system that consists

of a permeable reactive barrier, a subsurface flow constructed treatment wetland, and a contingency

treatment system as needed (as described in Part IV of the attached Fact Sheet) and is designed to meet the

effluent limitations listed in Part l.A.2. The system shall not be modified without written approval from

the Office of Water Resources."

RESPONSE NO. 6: The DEM concurs with the suggested changes and has incorporated the changes to

Part l.A.27.b of the draft permit.

COMMENT NO. 7: In regard to Part l.A.27 .c, ExxonMobil has proposed the following revision to provide

operational flexibility yet still adhere to the intent of the clause:

Part I.A.27.c to read as follows: "The flow through the ENS shall be measured via a flow meter and totalizer.

A logbook shall be kept to document the total flow discharged through the system."

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RESPONSE NO. 7: The DEM concurs with the suggested changes and has incorporated the changes to

Part l.A.27.c of the draft permit.

COMMENT NO. 8: In regard to Part LA.27.d, ExxonMobil has proposed the following revision:

Part I.A.27.d to read as follows: "The treatment system shall be inspected in accordance with the Final

O&M Manual dated January 20, 2017 and revised January 20, 2020, to assure the system is operating

efficiently. ExxonMobil may revise the O&M Manual in the future to optimize system performance and/or

respond to a change in conditions. As a result of these inspections, appropriate actions shall be taken

immediately to resolve any problems discovered during the inspection. Records documenting the

inspections and any actions taken shall be retained and made available to the Office of Water Resources

upon request."

RESPONSE NO. 8: The DEM concurs with the suggested changes and has incorporated the changes to

Part l.A.27.d of the draft permit.

COMMENT NO. 9: In regard to Part LA.27.e, ExxonMobil has proposed the following revision:

Part LA.27.e to read as follows: "Upon receipt oflaboratory data indicating exceedance of any oftbe limits

listed in Part I.A.2 from a sample collected from the Effluent Control Structure of the constructed treatment

wetland, the contingency treatment system will be placed into operation. Until such time that conformance

with limits in the Effluent Control Structure is achieved, the contingency treatment system will constitute

the sole discharge from this outfall. Should discharge from the contingency treatment system exceed any

of the limits listed in Part l.A.2, DEM shall be notified and a plan and schedule for improvements to the

system to achieve the discharge limits will be developed and agreed upon."

RESPONSE NO. 9: The language contained in Part l.A.27 .e is required for treatment systems to address

instances where they experience exceedances of effluent limits. Once laboratory data is received by the

operator of the system indicating exceedance of a numeric effluent limit( s) for the ENS permitted outfall,

the discharge must cease, and DEM must be notified. The discharge may recommence once steps have

been taken to ensure the limits will not be exceeded again and after DEM approval. When notifying DEM

of the exceedance, ExxonMobil can propose using the contingency treatment system to comply with

effluent limits in the interim until the cause of the exceedances is determined and a permanent ENS

corrective action is implemented by ExxonMobil. Based on the above information, no changes were made

to the draft permit.

COMMENT NO. 10: In regard to Part l.A.28.c, ExxonMobil has proposed the following revision to

provide operational flexibility yet still adhere to the intent of the clause:

Part l.A.28.c to read as follows: "The flow through the Tank 52/58 Treatment System shall be measured

via a flow meter and totalizer. A logbook shall be kept to document the start and end of each discharge and

the total flow discharged through the system."

RESPONSE NO. 10: The DEM concurs with the suggested changes and has incorporated the changes to

Part I.A.28.c of the draft permit.

COMMENT NO. 11: In regard to Part LA.28.d, ExxonMobil has proposed the following revision to

provide operational flexibility yet still adhere to the intent of the clause:

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Part LA.28.d to read as follows: "The treatment system shall be inspected at a minimum of once per day

when operating to assure the system is operating efficiently. As a result of these inspections, appropriate

actions shall be taken immediately to resolve any problems discovered during the inspection. Records

documenting the inspections and any actions taken shall be retained and made available to the Office of

Water Resources upon request."

RESPONSE NO. 11: The DEM concurs with the suggested changes and has incorporated the changes to

Part LA.28.d of the draft permit.

COMMENT N0.12: In regard to Part l.A.29.a, ExxonMobil has proposed the following revision to better

reflect present and future Terminal operations:

Part LA.29.a to read as follows: "Until closure of the Main Tank Farm Oil/Water Separator, all surface

runoff from the product storage area at the main tank farm and office/parking areas, and hydrostatic test

water shall be treated by the Main Tank Farm Oil/Water Separator prior to reaching Aeration Lagoon #1 in

the Vanity Fair Area. Upon startup of the Highland Tank Model HTC 25,000-gallon capacity aboveground

oil/water separator described in Part IV of the Fact Sheet, final treatment shall consist of that Highland

Tank Model HTC 25,000-gallon capacity aboveground oil/water separator."

RESPONSE NO. 12: The DEM concurs with the suggested changes and has incorporated the changes to

Part LA.29.a of the draft pennit.

COMMENT N0.13: In regard to Part LA.29.f, ExxonMobil has proposed the following revision to better

reflect present and future Terminal operations:

Part LA.29.f to read as follows: "A schedule for routinely inspecting and cleaning the Main Tank Farm

Oil/Water Separator for both sludge layer and oil layer shall be specified in the SWPPP, as needed. This

schedule will be developed based on the results of initial startup of the system. The permittee shall use the

same inspection frequency for the secondary containment areas as is specified for the oil/water separator

with cleaning being perfonned as necessary. In addition, the SWPPP shall identify procedures for insuring

compliance with the permit during such cleaning or maintenance periods."

RESPONSE NO. 13: The DEM concurs with the suggested changes and has incorporated the changes to

Part LA.29.f of the draft permit.

COMMENT NO. 14: In regard to Part LC, ExxonMobil has proposed the following revision to better

reflect feasible MDLs while still adhering to pennit effluent limitations:

Update the MDLs for the following pollutants as follows: Benzo (a) Anthracene (0.02 ppb), Benzo (a)

pyrene (0.03 ppb), Benzo (k) fluoranthene (0.02 ppb), Dibenzo (a,h) Anthracene (0.04 ppb).

In addition, ExxonMobil requests clarification on the MDL listed for Total Lead in Part LC (1.0 ppb) as

this MDL is greater than the Monthly Average limit for Total Lead in Part LA.2 of 0.44 ppb.

RESPONSE NO. 14: The DEM concurs with the proposed MDLs for Benzo (a) Anthracene, Benzo (a)

Pyrene, Benzo (k) Fluoranthene, and Dibenzo (a,h) Anthracene and has revised those MD Ls in Part LC. In

regard to the MDL for Total Lead, since the effluent limits contained in Part LA.2 have been removed from

the draft pennit and the proposed Total Lead monthly average limit for Outfall 600A is 68.1 ppb, an MDL

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of 1.0 ppb for Lead would be acceptable. As a result, no changes have been made to the Total Lead MDL

in the draft permit.

COMMENT NO. 15: In regard to Part I.D.2.c, ExxonMobil has proposed the following revision to reduce

the paperwork burden on DEM while still adhering to the intent of the permit requirements:

Part l.D.2.c was revised to remove the hard copy submission of priority pollutant scan results for Outfalls

001/002 and amendments to the SWPPP.

RESPONSE NO. 15: Since the submission ofSWPPP amendments occurs on an infrequent basis and will

require documentation in the DEM's permit file, the DEM does not consider the submission of SWPPP

amendments to be a paperwork burden. However, the submission of priority pollutant scan results has been

changed from hard copy to electronic.

COMMENT NO. 16: In regard to Fact Sheet Part III (Description of Discharge - Outfall 002A)

ExxonMobil has proposed the following revision to Page 3 of 13 of the Fact Sheet to better reflect the

nature of the discharge location of the ENS in the Silver Spring Golf Course area of the Vanity Fair area:

Fact Sheet Part III to read as follows: "Outfall 002A (newly proposed as Outfall 600A) discharges to the

Providence River via ephemeral features and a drainage ditch. In addition to discharge from the ENS, the

drainage ditch conveys storm water runoff from the Silver Spring Golf Course area and a series of catch

basins on Pawtucket Avenue ... "

RESPONSE NO. 16: Since the discharge from the ENS has been reconfigured to discharge through

Outfall 00 IA as indicated in the August 24, 2020 email from ExxonMobil to DEM and the monitoring

requirements originally contained in Part I.A.2 from the February 5, 2020 draft permit have been removed

from the public notice draft permit, the paragraph in Part III of the Fact Sheet regarding the discharge of

Outfall 002 to an unnamed freshwater stream has been removed.

COMMENT NO. 17: In regard to Fact Sheet Part IV (Description of the Facility and Discharge(s) -

Outfall 002A) ExxonMobil has proposed the following revision to Page 4 of 13 of the Fact Sheet to better

reflect the nature of the discharge of the ENS in the Silver Spring Golf Course area of the Vanity Fair area:

Fact Sheet Part IV to read as follows: "Outfall 002A: The discharge from Outfall 002A (newly proposed

as Outfall 600A) consists of treated effluent from the Silver Spring Golf Course - Vanity Fair Area

Engineered Natural System (ENS) and any identified allowable non-storm water discharges. Shallow

groundwater, surface water, and storm water in the Silver Spring Golf Course area of the Vanity Fair Area

is treated by an ENS that consists of a permeable reactive barrier (PRB), subsurface flow constructed

treatment wetland (CTW), and/or contingency treatment system (as-needed) prior to discharge from Outfall

002 to the Providence River via ephemeral features and a drainage ditch. The contingency treatment system

will operate only if discharge limitations are not met by the PRB and CTW ... "

RESPONSE NO. 17: As noted in Response No 16, due to the reconfiguration of the treated effluent from

the ENS and removal of Outfall 002 monitoring requirements, the DEM has revised the Part IV section of

the Fact Sheet regarding the proposed Outfall 600A, incorporating some of suggested edits above by

ExxonMobil.

COMMENT NO. 18: In regard to Fact Sheet Part IV (Description of the Facility and Discharge(s) -

Outfall 200A) ExxonMobil has proposed the following revision to Page 5 of 13 of the Fact Sheet to better

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reflect present and future Terminal operations:

Fact Sheet Part IV to read as follows: " ... The first phase of the treatment system will be up to three frac

tanks to provide temporary detention of contact water, the second phase of the system will be the compost

based NMF designed for removal of iron and ethanol, and the third phase will be an air stripper and off-gas

treatment to reduce the concentration ofVOCs ... "

RESPONSE NO. 18: The DEM concurs with the suggested changes and has incorporated the changes in

Part IV of the Fact Sheet pertaining to Outfall 200A.

COMMENT NO. 19: In regard to Fact Sheet Part IV (Description of the Facility and Discharge-Outfall

400A) ExxonMobil has proposed the following revision to Page 6 of 13 of the Fact Sheet to better reflect

present and future Terminal operations:

Fact Sheet Part IV to read as follows: " .. The following are the key design aspects as noted in the December

1 st^ submission:

Added to Bullet number 3: " ... pumped to Aeration Lagoon #1 in the Vanity Fair Area of the site. However,

upon start-up of the new OWS it may be determined that a lift station will not be necessary to convey treated

storm water to Aeration Lagoon # 1 if sufficient head pressure exists for a gravity feed."

Deleted Bullet number 4: "The wet well will contain a normally-closed valved outlet in the wells second

compartment that will bypass stonn water when rainfall exceeds 6.10 inches (25-year, 24-hour storm event).

When the valve is opened following the above 25-year event, storm water will back up into the 60-inch wet

well influent line and provide and estimated 25,000 gallons of storage capacity prior to bypass."

RESPONSE NO. 19: The DEM concurs with the suggested changes and has incorporated the changes to

Part IV of the Fact Sheet pertaining to Outfall 400A.

COMMENT NO. 20: In regard to Fact Sheet Part IV (Explanation of Effluent Limitation Derivation)

ExxonMobil has proposed the following revision to Page 9 of 13 of the Fact Sheet to better reflect present

and future Terminal operations:

Fact Sheet Part IV to read as follows:" ... For Outfalls l0OA and 300A, the permit requires monthly analysis

for benzene, toluene, ethylbenzene, total xylenes, total iron and naphthalene, and quarterly analysis of PAHs

(minus naphthalene). For Outfall 200A, the permit requires one analysis for every 817,000 gallons

discharged (one analysis for every 1/3 volume of Tank 58) for benzene, toluene, ethylbenzene, total xylenes,

and PAHs."

ExxonMobil also proposes the following additional revision to page 9 of 13 of the Fact Sheet to better

reflect the nature of the discharge of the ENS in the Silver Spring Golf Course area of the Vanity Fair area:

Fact Sheet Part IV to read as follows: "Outfall 002A: Effluent limitations for Outfall 002A (newly

proposed as Outfall 600A) were established ... to monitor the Silver Spring Golf Course Area - Vanity

Fair Area Engineered Natural System (ENS) and/or contingency treatment system (as-needed) ... "

RESPONSE NO. 20: Taking into consideration ofExxonMobil's comments for Part IV of the Fact Sheet

regarding Outfalls I 00, 200, and 300, DEM has incorporated the changes for outfalls JOO and 300. For

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Outfall 200A, the DEM is requiring samples to be taken equally spaced over the course of the discharge of

the Tank 52/58 contents due to the fact the volume contained may be variable. ExxonMobil can determine

the appropriate intervals for sampling at those times when the Tank 52/58 contents will need to be treated

and discharged via Outfall 200.

As noted in the previous responses, due to the reconfiguration of the treated effluent from the ENS and

removal of Outfall 002 monitoring requirements, the DEM has revised the Explanation of Effluent

Limitation Derivation for Part IV of the Fact Sheet regarding the proposed Outfall 600A, incorporating

some of suggested edits above by ExxonMobil. Also, as mentioned previously, the monthly average and

daily maximum effluent limits for all parameters (except Total Lead) for Outfall 600A were changed to the

limits proposed for Outfalls 100A, 200A, and 300A and effluent limits for Total Lead were adopted from

the 2019 RIPDES Remediation General Permit for the discharge category for petroleum sites containing

other pollutants discharging to a Class SA or SB receiving water.

The enclosed draft permit has been developed by this office and contains effluent limitations and conditions

to assure that the discharge receives adequate treatment and will not violate water quality standards. Also

enclosed is the Fact Sheet, which describes the basis for the permit conditions. As can be seen from the

attached public notice, the DEM has initiated the public notice of the proposed reissuance of the

ExxonMobil Pipeline Company RIPDES Permit No. RIOO0l333. Formal comments can be made during

the public comment period and must be submitted to the DEM by November 6, 2020, as described in the

attached public notice document. DEM will officially respond to all significant comments raised during

the public comment period and at the Public Hearing (if necessary). You are encouraged to closely review

all terms and conditions contained in the draft permit and fact sheet that is being sent to public notice.

The law requires public notice to be given of the preparation of a draft permit to allow opportunity for

public comments and, if necessary, a public hearing. In order to preserve the right to a formal hearing to

contest provisions in a final permit, all persons, including the applicant, who believe any condition of the

draft is inappropriate, must raise all reasonably ascertainable issues and submit all reasonably available

arguments and factual grounds supporting their position, including all supporting material, by the close of

the public comment period. Following the close of the public comment period, your final permit will be

issued providing no new substantial questions are raised. If new questions develop during the comment

period, it may be necessary to draft a new permit, revise the Fact Sheet, and/or reopen the public comment

period. Any additional details regarding the public notice and public hearing can be found in the attached

public notice document, PN20-04.

If ExxonMobil has any questions regarding the public notice or would like to discuss any of the conditions

contained in this draft permit, do not hesitate to contact Aaron Mello of the RIPDES Permitting Program at

(401) 222-4700, extension 7405.

Sin?Jely, ;/A <'7 / /_ _

/~/fl{ [).-ff/'L-

toseph B. Haberek, P.E.

/Environmental Engineer IV

JBH:am

Enclosures

PublicNoticeCoverwExxonMobil 2020

Ms. Arny Weinberger October 2, 2020 Page IOoflO

cc: Emma Clements, ExxonMobil Pipeline Company (Electronic Copy)

Thomas Henderson, Roux Associates, Inc. (Electronic Copy)

Bryan Crowley, Roux Associates, Inc. (Electronic Copy)

Crystal Charbonneau, DEM/OWR (Electronic Copy)

PublicNoticeCover~ExxonMobil 2020

Permit No. RI Page 1 of 28

AUTHORIZATION TO DISCHARGE UNDER THE

RHODE ISLAND POLLUTANT DISCHARGE ELIMINATION SYSTEM

In compliance with the provisions of Chapter 46-12 of the Rhode Island General Laws, as amended,

ExxonMobil Pipeline Company 22777 Springwoods Village Parkway Room No. E.3.SA. Spring, Texas 77389

is authorized to discharge from a facility located at

ExxonMobil Oil Corporation • East Providence Terminal 1001 Wampanoag Trail East Providence, Rhode Island 02915

to receiving waters named Providence River

in accordance with effluent limitations, monitoring requirements and other conditions set forth herein.

This Permit shall become effective on ____ _

This permit and the authorization to discharge expire at midnight, five (5) years from the date of signature.

This permit supersedes the permit issued on September 30, 2008.

This permit consists of 28 pages in Part I including effluent limitations, monitoring requirements, etc. and 10 pages in Part II including General Conditions.

Signed this_ day of ____~ 2020.

DRAFT

Angelo S. Liberti, P.E., Administrator of Surface Water Protection Office of Water Resources Rhode Island Department of Environmental Management Providence, Rhode Island

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI Page 2 of 28 PARTI

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

1. During the period beginning on the effective date and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 001A. (Overflow Weir from Second Lagoon). Such discharges shall be limited and monitored by the permittee as specified below:

Effluent Discharge Limitations (^) Monitoring Reguirement Characteristic Quantity - lbs./day (^) Concentration - specify units Average Maximum (^) Average Average Maximum Measurement Sample Monthly Daily (^) Monthly Weekly Daily Freguency (^) ~ *(Minimum) *(Average) *(Maximum) Flow (^) --- MGD (^) --- MGD Continuous (^) Recorder

TSS (^21) mg/I 33 mg/I 2/Month^1 -^3 Grab

Oil and Grease (^) --- mg/I 15 mg/I 2/Month^1 ,^3 Grab

Benzene (^) --- μg/I -- μg/I 1/Month^2 -^3 Grab

Toluene (^) -- μg/I (^) --- μg/I 1/Month^2 ,^3 Grab

Ethyl-benzene (^) --- μg/I --- μg/I 1/Month2 3, (^) Grab

Total Xylenes (^) --- μg/I (^) --- μg/I 1/Month^2 -^3 Grab

(^1) The two (2) grab samples shall be taken as follows: one when the separator at Main Tank Farm is being pumped with proper allowances for hydraulic detention time (time for flow to travel from separator to overflow weir) and one ( 1) during dry weather or when the pumps at the Main Tank Farm are not in operation. If the separator at the Main Tank Farm cannot be pumped under normal operating conditions, the two (2) samples for TSS, and Oil and Grease for the current month shall be taken during dry weather (when the pumps at the Main Tank Farm are not in operation).

(^2) The one grab sample shall be taken when the Main Tank Farm Separator is being pumped, giving proper allowances for hydraulic detention time (time for flow to travel from separator to overflow weir). If pumping cannot occur under normal operating conditions, BTEX sampling shall be suspended for that month.

(^3) The permittee must keep a log of times when the pumps at the Main Tank Farm are in operation, and maintain the log data on-site for 5 years.

--- Signifies a parameter which must be monitored and data must be reported; no limit has been established at this time.

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 001 A - overflow weir from second lagoon.

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI Page 3 of 28 PART!

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

2. During the period beginning on the effective date and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 100A. (Effluent from PCS Groundwater Treatment System). Such discharges shall be limited and monitored by the permittee as specified below:

Effluent (^) Discharge Limitations (^) Monitoring Reguirement Characteristic (^) Quantity - lbs./day Concentration - specify units Average Maximum Average (^) Average Maximum (^) Measurement Sample

Monthly Daily Monthly Weekly Daily Freguency -1Yilll

Flow --gpm (^) 600 gpm (^) Continuous' Recorder

Benzene (^) 5.0 μg/I 5.0 μg/I (^) 1/Month Grab

Toluene (^) 10.0 μg/I 10.0 μg/I (^) 1/Month Grab

Ethylbenzene (^) 10.0 μg/I (^) 10.0 μg/I 1/Month Grab

Total Xylenes (^) 30.0 μg/I 30.0 μg/I (^) 1/Month Grab

Total BTEX (^2) --- μg/I (^) --- μg/I 1/Month Grab

MTBE (^) -- μg/I (^) 70.0 μg/I 1/Month Grab

Naphthalene (^) 10.0 μg/I 10.0 μg/I (^) 1/Month Grab

Total Iron (^) -- μg/I (^) -- μgit 1/Month Grab

(^1) Monitor flow and submit a flow log with the monitoring results. The flow log shall include the rate and duration of flow including the time( s) of day when flow

commences and ceases. In addition, the flow log shall specify the volume and flow rates associated with flows, if any, generated from Tank 58.

(^2) Sum of benzene, toluene, ethylbenzene and total xylenes.

--- signifies a parameter which must be monitored and data must be reported; no limit has been established at this time.

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 100A- effluent from Perimeter Containment System (PCS) groundwater treatment system.

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI Page 4 of 28 PARTI

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

3. During the period beginning on the effective date and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 100A. (Effluent from PCS Groundwater Treatment System). Such discharges shall be limited and monitored by the permittee as specified below:

Effluent Characteristic

Discharge Limitations Quantity - lbs./day (^) Concentration - specify units

Monitoring Reguirement

Average Monthly

Maximum Daily

Average Monthly

Average Weekly

Maximum Daily

Measurement Freguency

Sample ~

Acenaphthene (^) 10.0 μg/I 10.0 μg/I (^) Quarterly Grab

Acenaphthylene (^) 10.0 μg/I (^) 10.0 μg/I Quarterly Grab

Anthracene (^) 10.0 μg/I (^) 10.0 μg/I Quarterly (^) Grab

Benzo (a) Anthracene (^) 1.44 μg/I (^) 1.44 μg/I Quarterly (^) Grab

Benzo (a) Pyrene (^) 1.44 μg/I (^) 1.44 μg/I Quarterly Grab

Benzo (b) Fluoranthene (^) 1.44 μg/I (^) 1.44 μg/1 Quarterly (^) Grab

Benzo (ghi) Perylene (^) 41.0 μg/1 (^) 41.0 μg/1 Quarterly (^) Grab

Benzo (k) Fluoranthene (^) 1.44 μg/1 (^) 1.44 μg/1 Quarterly (^) Grab

Chrysene (^) 1.44 μg/1 (^) 1.44 μg/1 Quarterly (^) Grab

Dibenzo (a,h) Anthracene (^) 1.44 μg/1 (^) 1.44 μg/I Quarterly (^) Grab

Fluoranthene (^) 10.0 μg/1 10.0 μg/I Quarterly (^) Grab

Fluorene (^) 10.0 μg/1 10.0 μg/1 (^) Quarterly Grab

lndeno ( 1, 2, 3 - cd) Pyrene (^) 1.44 μg/I 1.44 μg/I (^) Quarterly Grab

Phenanthrene (^) 10.0 μg/I 10.0 μg/1 (^) Quarterly (^) Grab

Pyrene (^) 10.0 μg/I 10.0 μg/I (^) Quarterly Grab

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 1DOA - effluent from PCS groundwater treatment system.

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI Page 5 of 28 PART!

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

4. During the period beginning on the effective date and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 200A. (Effluent from Tank 52/58 Treatment System). Such discharges shall be limited and monitored by the permittee as specified below:

Effluent (^) Discharge Limitations (^) Monitoring Requirement Characteristic (^) Quantity - lbs./day (^) Concentration - specify units Average Maximum (^) Average Average Maximum (^) Measurement Sample Monthly Daily (^) Monthly Weekly Daily Frequency (^) ~

Flow (^) --- gpm 20gpm (^) Continuous^1 Recorder

Flow (Volume) (^) --- MG (^) Continuous Recorder

Benzene (^) 5.0 μg/I 5.0 μg/I (^) 3/Discharge^2 Grab

Toluene (^) 10.0 μg/I (^) 10.0 μg/I 3/Discharge^2 Grab

Ethyl benzene (^) 10.0 μg/I 10.0 μg/I (^) 3/Discharge^2 Grab

Total Xylenes (^) 30.0 μg/I 30.0 μg/I (^) 3/Discharge (^2) Grab

Total BTEX^3 --- μg/I (^) --- μg/I 3/Discharge (^2) Grab

Ethanol (^4) --- μg/I (^) --- μg/I 3/Discharge (^2) Grab

Total Iron (^) --- μg/I (^) --- μg/I 3/Discharge (^2) Grab

(^1) Monitor flow and submit a flow log with the monitoring results. The flow log shall include the rate and duration of flow including the time(s) of day when flow commences and ceases. The average monthly flow should be based on the days of the month that there is a discharge from the treatment system.

(^2) The three (3) grab samples shall be equally spaced over the course of drainage of Tank 52/58 and should be representative of the contents of the entire tank.

(^3) Sum of benzene, toluene, ethylbenzene and total xylenes.

(^4) Ethanol shall be analyzed using EPA Method 8260.

---signifies a parameter which must be monitored and data must be reported; no limit has been established at this time.

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 200A - effluent from Tank 52/ treatment system.

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI Page 6 of 28

PART!

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

5. During the period beginning on the effective date and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 200A. (Effluent from Tank 52/58 Treatment System). Such discharges shall be limited and monitored by the permittee as specified below:

Effluent Characteristic

Discharge Limitations Quantity - lbs./day (^) Concentration - specify units

Monitoring Reguirement

Average Monthly

Maximum Daily

Average Monthly

Average Weekly

Maximum Daily

Measurement Freguency

Sample __lyQg

Acenaphthene (^) 10.0 μg/I (^) 10.0 μg/I 3/Discharge (^1) Grab

Acenaphthylene (^) 10.0 μg/I (^) 10.0 μg/I 3/Discharge (^1) Grab

Anthracene (^) 10.0 μg/I (^) 10.0 μg/I 3/Discharge^1 Grab

Benzo (a) Anthracene (^) 1.44 μg/I (^) 1.44 μg/I 3/Discharge (^1) Grab

Benzo (a) Pyrene (^) 1.44 μg/I (^) 1.44 μg/I 3/Discharge 1 Grab

Benzo (b) Fluoranthene (^) 1.44 μg/I (^) 1.44 μg/I 3/Discharge (^1) Grab

Benzo (ghi) Perylene (^) 41.0 μg/I (^) 41.0 μg/I 3/Discharge^1 Grab

Benzo (k) Fluoranthene (^) 1.44 μg/I (^) 1.44 μg/I 3/Discharge (^1) Grab

Chrysene (^) 1.44 μg/I (^) 1.44 μg/I 3/Discharge (^1) Grab

Dibenzo (a,h) Anthracene (^) 1.44 μg/I 1.44 μg/I (^) 3/Discharge (^1) Grab

Fluoranthene (^) 10.0 μg/I 10.0 μg/I (^) 3/Discharge (^1) Grab

Fluorene (^) 10.0 μg/I (^) 10.0 μg/I (^) 3/Discharge (^1) Grab

lndeno (1, 2, 3 - cd) Pyrene (^) 1.44 μg/I (^) 1.44 μg/I (^) 3/D ischarge 1 Grab

Naphthalene (^) 10.0 μg/I (^) 10.0 μg/I (^) 3/Discharge (^1) Grab

Phenanthrene (^) 10.0 μg/I (^) 10.0 μg/1 (^) 3/Discharge (^1) Grab

Pyrene (^) 10.0 μg/I (^) 10.0 μg/I 3/Discharge (^1) Grab

(^1) The three (3) grab samples shall be equally spaced over the course of drainage of Tank 52/58 and should be representative of the contents of the entire tank.

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 200A - effluent from Tank 52/ treatment system.

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI Page 7 of 28

PART I

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

6. During the period beginning on the effective date and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 300A. (Effluent from the Vanity Fair Cliffs Area Recovery/Treatment System). Such discharges shall be limited and monitored by the permittee as specified below:

Effluent Characteristic

Discharge Limitations Quantity - lbs./day (^) Concentration - specify units

Monitoring Requirement

Average Monthly

Maximum Daily

Average Monthly

Average Weekly

Maximum Daily

Measurement Frequency

Sample

-1Yllli

Flow (^) --- gpm 10.0 gpm (^) Continuous' (^) Recorder

Benzene (^) 5.0 μg/I 5.0 μg/I (^) 1/Month Grab

Toluene (^) 10.0 μg/I (^) 10.0 μg/I 1/Month (^) Grab

Ethyl benzene (^) 10.0 μg/I (^) 10.0 μgA 1/Month Grab

Total Xylenes (^) 30.0 μg/I 30.0 μg/I (^) 1/Month Grab

Total BTEX (^2) --- μg/I (^) --- μg/I 1/Month (^) Grab

MTBE (^) --- μg/I (^) 70.0 μg/I 1/Month (^) Grab

Naphthalene (^) 10.0 μg/I (^) 10.0 μg/I 1/Month (^) Grab

Total Iron (^) --- μg/I (^) --- μg/I 1/Month Grab

'Monitor flow and submit a flow log with the monitoring results. The flow log shall include the rate and duration of flow including the time(s) of day when flow commences and ceases.

(^2) Sum of benzene, toluene, ethylbenzene and total xylenes.

---signifies a parameter which must be monitored and data must be reported; no limit has been established at this time.

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 300A - effluent from the Vanity Fair Cliffs Area Recovery/Treatment System.

PARTI

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI Page 8 of 28 A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

7. During the period beginning on the effective date and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 300A. (Effluent from the Vanity Fair Cliffs Area Recovery/Treatment System). Such discharges shall be limited and monitored by the permittee as specified below:

Effluent Characteristic

Discharge Limitations Quantity - lbs./day (^) Concentration - specify units

Monitoring Reguirement

Average Monthly

Maximum Daily

Average Monthly

Average Weekly

Maximum Daily

Measurement Freguency

Sample ~

Acenaphthene (^) 10.0 μg/I (^) 10.0 μg/I Quarterly (^) Grab

Acenaphthylene (^) 10.0 μg/I (^) 10.0 μg/I (^) Quarterly Grab

Anthracene (^) 10.0 μg/I 10.0 μg/I (^) Quarterly Grab

Benzo (a) Anthracene (^) 1.44 μg/I (^) 1.44 μg/I Quarterly (^) Grab

Benzo (a) Pyrene (^) 1.44 μg/I (^) 1.44 μg/I (^) Quarterly Grab

Benzo (b) Fluoranthene (^) 1.44 μg/I (^) 1.44 μg/I Quarterly (^) Grab

Benzo (ghi) Perylene (^) 41.0 μg/I 41.0μg/l (^) Quarterly Grab

Benzo (k) Fluoranthene (^) 1.44 μg/I 1.44 μg/I (^) Quarterly Grab

Chrysene (^) 1.44 μg/I 1.44 μg/1 (^) Quarterly (^) Grab

Dibenzo (a,h) Anthracene (^) 1.44 μg/I (^) 1.44 μg/1 Quarterly Grab

Fluoranthene (^) 10.0 μg/1 (^) 10.0 μg/1 Quarterly (^) Grab

Fluorene (^) 10.0 μg/1 10.0 μg/1 Quarterly (^) Grab

lndeno (1, 2, 3 - cd) Pyrene (^) 1.44 μg/1 1.44 μg/1 (^) Quarterly Grab

Phenanthrene (^) 10.0 μg/I (^) 10.0 μg/I Quarterly (^) Grab

Pyrene (^) 10.0 μg/I (^) 10.0 μg/I Quarterly (^) Grab

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 300A - effluent from the Vanity Fair Cliffs Area Recovery/Treatment System.

PART!

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI Page 9 of 28 A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

8. During the period beginning on the effective date and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 400A. (Effluent from the Main Oil Water Separator). Such discharges shall be limited and monitored by the permittee as specified below:

Effluent Characteristic

Discharge Limitations Quantity - lbs./day (^) Concentration - specify units

Monitoring Requirement

Average Maximum (^) Average Average Maximum Monthly Daily (^) Monthly Weekly Daily

Measurement (^) Sample Frequency (^) ~

Flow (^) --gpm --gpm (^) 1/Month Estimate

TSS (^) ---μg/I --- μg/I (^) 1/Month Grab

Oil and Grease (^) --- μg/1 (^) --- μg/I 1/Month Grab

Benzene (^) --- μg/I (^) --- μg/1 1/Month Grab

Toluene (^) --- μg/1 (^) --- μg/1 1/Month (^) Grab

Ethyl-benzene (^) --- μg/I (^) --- μg/I 1/Month Grab

Total Xylenes (^) --- μg/I (^) --- μg/I 1/Month Grab

Ethanol' (^) --- μg/I (^) --- μg/I 1/Month (^) Grab

--- Signifies a parameter which must be monitored and data must be reported; no limit has been established at this time.

(^1) Ethanol shall be analyzed using EPA Method 8260.

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 400A - effluent from the Main Oil Water Separator.

Rl0001333-ExxonMobil-PN Draft 2020

Permit No. RI Page 10 of 28 PARTI

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

9. During the period beginning on the effective date and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 500A. (Effluent from the Vanity Fair Cliffs Area Oil Water Separator). Such discharges shall be limited and monitored by the permittee as specified below:

Effluent Characteristic

Discharge Limitations Quantity - lbs./day (^) Concentration - specify units

Monitoring Requirement

Average Monthly

Maximum Daily

Average Monthly

Average Weekly

Maximum Daily

Measurement Frequency

Sample ~

Flow (^) ---gpm ---gpm (^) 1/Month Estimate

TSS (^) --- μg/I (^) --- μg/I 1/Month Grab

Oil and Grease (^) --- μg/I (^) --- μg/I 1/Month Grab

Benzene (^) --- μg/I (^) --- μg/I 1/Month (^) Grab

Toluene (^) --- μg/I --- μg/I (^) 1/Month Grab

Ethyl-benzene (^) --- μg/I (^) --- μg/I 1/Month Grab

Total Xylenes (^) --- μg/I (^) --- μg/I 1/Month Grab

--- Signifies a parameter which must be monitored and data must be reported; no limit has been established at this time.

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 500A- effluent from the Vanity Fair Cliffs Area Oil Water Separator.

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI0001333 Page 11 of 28

PARTI

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

10. During the period beginning on the date that the Engineered Natural System (ENS) Treatment System's discharge ceases flow to the unnamed tributary to the Providence River and is replaced as internal Outfall 600A that will discharge to the Providence River through Outfall 001 A and lasting through permit expiration, the permittee is authorized to discharge from outfall serial number 600A. (Effluent Control Structure from the Engineered Natural System (ENS) Treatment System, or the contingency treatment system effluent, when the contingency treatment system is operating). Such discharges shall be limited and monitored by the permittee as specified below: Effluent Characteristic

Discharge Limitations Quantity - lbs./day (^) Concentration - specify units

Monitoring Requirement

Average Monthly

Maximum Daily

Average Monthly

Average Weekly

Maximum Daily

Measurement Frequency

Sample ~

Flow (^) --- gpm 70gpm (^) Continuous (^1) Recorder

Benzene (^) 5.0 μg/I (^) 5.0 μg/I 1/Month Grab

Toluene (^) 10.0 μg/I (^) 10.0 μg/I 1/Month (^) Grab

Ethylbenzene (^) 10.0 μg/I (^) 10.0 μg/I 1/Month (^) Grab

Total Xylenes (^) 30.0 μg/I 30.0 μg/I (^) 1/Month Grab

Total BTEX (^2) --- μg/I --- μg/I 1/Month Grab

MTBE (^) --- μg/I (^) 70.0 μg/I 1/Month (^) Grab

Naphthalene (^) 10.0 μg/I 10.0 μg/I (^) 1/Month Grab

Total Iron (^) --- μg/I (^) --- μg/I 1/Month (^) Grab

Total Lead (^) 68.1 μg/I 1,600 μg/I (^) 1/Month Grab

(^1) Monitor flow and submit a flow log with the monitoring results. The flow log shall include the volume, rate and duration of flow generated from the ENS.

(^2) Sum of benzene, toluene, ethylbenzene and total xylenes.

--- signifies a parameter which must be monitored and data must be reported; no limit has been established at this time.

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following locations: Outfall 600A - Effluent Control Structure from the Engineered Natural System (ENS) treatment system, or the contingency treatment system effluent, when the contingency treatment system is operating.

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI0001333 Page 12 of 28

11,

a. The pH of the effluent shall not be less than 6.0 nor greater than 9.0 standard units at any time, unless these values are exceeded due to natural causes or as a result of the approved treatment processes.

b. The discharge shall not cause visible discoloration of the receiving waters.

c. The effluent shall contain neither a visible oil sheen, foam, nor floating solids at anytime.

12. All existing manufacturing, commercial, mining, and silvicultural dischargers must notify the Director as soon as they know or have reason to believe:

a. That any activity has occurred or will occur which would result in the discharge, on a routine or frequent basis, of any toxic pollutant which is not limited in the permit, if that discharge will exceed the highest of the following "notification levels":

(1) One hundred micrograms per liter (100 μg/I);

(2) Two hundred micrograms per liter (200 μg/I) for acrolein and acrylonitrile, five hundred micrograms per liter (500 μg/I) for 2,4-dinitrophenol and for 2-methyl-4,6-dinitro-phenol, and one milligram per liter (1 mg/I) for antimony;

(3) Five (5) times the maximum concentration value reported for that pollutant in the permit application in accordance with 40 CFR s122.21 (g)(7), or;

(4) Any other notification level established by the Director in accordance with 40 CFR s122.44(f) and Rhode Island Regulations.

b. That any activity has occurred or will occur which would result in the discharge, on a non-routine or infrequent basis, of any toxic pollutant which is not limited in the permit, if that discharge will exceed the highest of the following "notification levels":

(1) Five hundred micrograms per liter (500 μg/I);

(2) One milligram per liter (1 mg/I) for antimony;

(3) Ten (10) times the maximum concentration value reported for that pollutant in the permit application in accordance with 40 CFR s122.21(g)(7), or;

(4) Any other notification level established by the Director in accordance with 40 CFR s122.44(f) and Rhode Island Regulations.

c. That they have begun or expect to begin to use or manufacture as an intermediate or final product or by-product any toxic pollutant which was not reported in the permit application,

13. The permittee shall analyze the effluent from Outfall 001A and 600A annually for the EPA Priority Pollutants as listed in 40 CFR 122, Appendix D, Tables II and Ill. The results of these analyses shall be submitted to the Department of Environmental Management by January 15th^ for the previous calendar year. All sampling and analysis shall be done in accordance with EPA Regulations, including 40 CFR 136 or other methods approved in this permit, grab and composite samples shall be taken as appropriate.

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI0001333 Page 13 of 28

14. This permit serves as the State's water quality certification for the discharges described herein.
15. The permittee shall operate and maintain the Perimeter Containment System (PCS) in accordance with Order of Approval No. SROA 95-024 issued by RIDEM. Mechanical failure or breakthrough of the PCS system (exceed a nee of any permit limits) shall be immediately reported to the Office of Water Resources and the Office of Waste Management.
16. The permittee shall operate and maintain the Silver Springs Golf Course - Vanity Fair Area Engineered Natural System (ENS), consisting of a constructed treatment wetland, permeable reactive barrier, and contingency treatment system in accordance with the Order of Approval No. SR-10-0831 E issued by RIDEM on September 16, 2015. Mechanical failure or breakthrough of the ENS (exceedance of any permit limits) shall be immediately reported to the Office of Water Resources and the Office of Waste Management.
17. The addition of chemicals (i.e., disinfecting agents, detergents, emulsifiers, etc.) to the collection and treatment system is prohibited without prior approval by the Department. This prohibition will prevent the carryover of hydrocarbons and/or particulate matter to the Providence River. This prohibition does not apply to the addition of Percol 726 or 727, sodium hypochlorite, and aluminum chlorohydrate (per acceptance in the March 5, 1996 letter from the Department) to the PCS groundwater treatment system.
18. The permittee shall not discharge any sludge and/or bottom deposits from any storage tank, basin and/or diked area to the receiving water. Examples of storage tanks and/or basins include, but are not limited to: primary catch basins, stilling basins, the oil/water separator, observation basins with baffles, petroleum product storage tanks, baffied storage tanks collecting spills, and tank truck loading rack sumps.
19. This permit does not authorize discharges to the separate storm sewer system or to waters of the State from floor drains and trench drains located inside of buildings. These discharges may, however, be discharged to either the Tank 52/58 treatment system or the PCS groundwater treatment system, provided the discharge does not cause a permit violation.
20. There shall be no direct discharge to the Southern Operations and/or Vanity Fair oil/water separators, or to the lagoons of untreated tank bottom draw off water (water which separates from product during storage and settles to the tank bottom); untreated marine transportation water (water which separates and/or accumulates during marine transportation); tank truck wash water, storm water and wash water from spill tank at truck loading rack; vehicle or equipment washing activities; and ship barge/bilge water. These discharges may, however, be discharged to either the Tank 52/58 treatment system or the PCS groundwater treatment system, provided the discharge does not cause a permit violation.
21. This permit does not authorize the discharge of sanitary waste water to waters of the Slate.
22. This permit authorizes the discharge of groundwater from the recovery wells, as described in the Remedial Action Work Plan for the Groundwater Treatment Component of the Perimeter Containment System, dated January 13, 1995, to the PCS groundwater treatment system. In addition, this permit authorizes the discharge of well development/purge water from the monitoring wells, as described in the September 18, 1995 letter from Mobil to RIDEM, to the PCS groundwater treatment system. Also, this permit authorizes the discharge of water generated from a vapor/liquid separator associated with soil vapor extraction/air sparging in the vicinity of former tank No. 66 (North Operations) to the PCS groundwater treatment system, as described in the March 3, 1998 letter from RIDEM to ExxonMobil Oil Corporation. Authorization to discharge additional sources of contaminated groundwater to the PCS system shall only be granted upon receipt of satisfactory qualitative data that demonstrates the additional sources of

RI0001333-ExxonMobil-PN Draft 2020

Permit No. RI0001333 Page 14 of 28

groundwater are substantially the same as that of the PCS influent. Contaminated groundwater generated from recovery or monitoring wells during site investigation and remediation shall not be discharged to or placed in either oil/water separator. Infiltration/inflow of contaminated groundwater into the storm water collection system or into either oil/water separator shall be addressed by the permittee pursuant to Rules and Regulations for the Investigation and Remediation of Hazardous Material Releases ("Remediation Regulations") under the direction of the Office of Waste Management, in association with the Office of Water Resources. Nothing in this paragraph shall be construed to relieve permittee's obligation to investigate and/or remediate contaminated groundwater in compliance with the Remediation Regulations or the regulations of the Office of Water Resources.

23. This permit authorizes the discharge of treated shallow groundwater, surface water and stormwater in the Silver Springs Golf Course of the Vanity Fair Area, as described in the Remedial Action Work Plan for Installation of an Engineered Natural System (ENS), Silver Springs Golf Course - Vanity Fair Area, dated July 7, 2014, from an Engineered Natural System consisting of a permeable reactive barrier, subsurface flow constructed treatment wetland, and contingency treatment system. Nothing in this paragraph shall be construed to relieve the permittee's obligation to investigate and/or remediate contaminated groundwater in the compliance with the Remediation Regulations or the Regulations of the Office of Water Resources.
24. Unless identified by the permittee or the DEM as significant sources of pollutants to waters of the United States, the following non-storm water discharges are authorized under this permit to enter the storm water drainage system: discharges from firefighting activities; fire hydrant flushings; routine external building washdown / power wash water that does not use detergents or hazardous cleaning products (such as those containing bleach, hydrofluoric acid, muriatic acid, sodium hydroxide, nonylphenols); lawn watering; uncontaminated groundwater; springs; air conditioning condensate; potable waterline flushings; irrigation drainage; foundation or footing drains where flows are not contaminated with process materials, such as solvents, or contaminated by contact with soils, where spills or leaks of toxic or hazardous materials have occurred; water sprayed for dust control or at a truck load wet-down station; incidental windblown mist from cooling towers that collects on rooftops or adjacent portions of the facility, but NOT intentional discharges from the cooling towner (e.g., "piped" cooling tower blowdown or drains); uncontaminated utility vault dewatering; dechlorinated water line testing water; hydrostatic test water that does not contain any treatment chemicals and is not contaminated with process chemicals; discharges from washing of vehicles provided: chemicals, soaps, detergents, hazardous cleaning products (such as those containing bleach, hydrofluoric acid, muriatic acid, sodium hydroxide, nonylphenols), steam, or heated water are not used; cleaning is restricted to the outside of the vehicle (e.g., no engines, transmissions, undercarriages, or truck beds); or washing is not used to remove accumulated industrial materials, paint residues, heavy metals or any other potentially hazardous materials from surfaces; and discharges from washing of marine vessels provided chemicals, soaps, detergents, hazardous cleaning products (such as those containing bleach, hydrofluoric acid, muriatic acid, sodium hydroxide, nonylphenols), steam, or heated water are not used an the washing is not used to remove topside or bottom paint; marine growth, or other potentially hazardous materials from vessels. If any of these discharges may reasonably be expected to be present and to be mixed with storm water discharges, they must be specifically identified and addressed in the facility's Storm Water Pollution Prevention Plan (SWPPP) required in Part I.B.
25. The discharge of tank bottom draw off water or other wastewaters (including contaminated groundwater) generated off-site is strictly prohibited. This exclusion does not apply to the discharge of groundwater contaminated by sources which have originated and/or emanated from terminal property.

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Permit No. RI0001333 Page 15 of 28

26. The permittee shall notify the Office of Water Resources at least twenty-four (24) hours prior to the commencement of any proposed hydrostatic-test water discharges.

Prior to testing tank(s), the interior of the tank(s) being tested shall be cleaned and certified to be free of petroleum product. There shall be no discharge of tank cleaning residual/debris to either of the oil/water separators or lagoons. At a minimum, four (4) representative samples shall be taken of the hydrostatic-test water: one (1) grab sample of the influent (water added to the tank) and three (3) serial-grab samples of the effluent (test water discharged from the tank), which after treatment though the oil water separator and two lagoons is discharged to the receiving waters. The influent grab sample shall be taken approximately midway through the fill segment of the hydrostatic-test procedure. The three (3) effluent serial-grab samples shall be taken over the duration of the entire discharge segment of the hydrostatic-test procedure. The first serial-grab sample shall be taken during the initial phase of the discharge; the second serial grab sample is to be taken midway through the discharge; and the final sample shall be taken at the end of the discharge. All effluent samples should be taken directly from the effluent of the tank prior to discharge into the oil/water separator and/or mixing with any other authorized waste streams. These samples should provide adequate characterization of the influent and effluent hydrostatic-test water and shall be analyzed for the following parameters:

a. Total Suspended Solids (TSS) d. Chemical Oxygen Demand (COD)

b. Oil & Grease e. Dissolved Oxygen (DO) C. Total Iron f. pH

Hydrostatic testing of piping is limited to piping that has been in hydrocarbon service before. At a minimum one (1) representative sample of the discharge from pipe testing shall be taken from the final collection tank(s) holding the hydrostatic test water. The sample will be made up of equal parts of grab samples taken from each tank. The grab samples will be taken from the top, middle and bottom of water column in each tank and then composited. All samples should be taken and analytical results received prior to discharge into the oil/water separator. These samples shall be analyzed for the following parameters:

a. Total Suspended Solids (TSS)^ b. Oil & Grease (O/G)

All hydrostatic test waters released from the tank(s) and/or pipe(s) must satisfy all the effluent limitations and conditions of this permit after treatment through the oil/water separator and lagoons. The surface of the oil/water separator should be routinely observed during hydrostatic test water discharges to determine if there is any detectable increase in the separated oil layer to prevent inadvertent hydrocarbon release to the receiving water(s). A logbook shall be kept to document the start and end of each hydrostatic test, the total flow discharged and all monitoring data.

Should any visual inspection or suspicious odor indicate the presence of petroleum while inspecting the oil/water separator as required above or if laboratory results from the samples of the discharge become available that indicate an exceedance of the permit effluent limits, the transfer shall be halted immediately followed by notification to the RI DEM of the suspended discharge. After the discharge of the hydrostatic test water has been completed, the permittee shall submit a letter/report to the RI DEM within thirty (30) days, summarizing the results of the transfer. This report shall contain: the date(s) of hydrostatic test water transfer; the volume of hydrostatic test water transferred; and the analytically determined values of the discharge parameters.

27. Silver Springs Golf Course - Vanity Fair Area Engineered Natural System:

a. The permittee shall properly operate and maintain the Silver Springs Golf Course

• Vanity Fair Area Engineered Natural System (ENS). Mechanical failure or breakthrough of the treatment system (exceedance of any permit limits) shall be immediately reported to the Office of Water Resources.

RI0001333-ExxonMobil-PN Draft 2020