microsoft outlook - memo style · (2) the concentration of methane gas does not exceed the lower...

1

Blue, Karen

From: Arjmandi, MasoudSent: Friday, September 28, 2018 9:16 AMTo: Blue, KarenCc: Cusher, AnnetteSubject: FW: Upper Southwest Permit ModificationAttachments: 2018 USARSWMD Update Gas Monitoring Plan.pdf; PC Est-2018 All Permitted

Areas.pdf; Section 22.pdf

From: Lance Powell [mailto:[email protected]]Sent: Friday, September 28, 2018 8:25 AM To: Arjmandi, Masoud Subject: Upper Southwest Permit Modification

Masoud,

I have attached the documents and pages that were affected by the changes we discussed via telephone associated withthe class 1 landfill permit modification application. Please let me know if you have questions about anything.

Thanks,

Lance Powell, P.E.MemberCIVIL ENGINEERING ASSOCIATES, LLC2114 East Matthews AvenueJonesboro, Arkansas 72401

Phone: (870) 972 5316Fax: (870) 932 0432Mobile: (870) 243 9400

Rec’d Digitally

AFIN:_________________________

PMT#:_________________________ SW

DOC ID#:______________________ MD

TO:___________________________

By Karen Blue at 10:40 am, Sep 28, 2018

31-00107

0265-S1-R1

74632

AC>FILE <KMB

Reliable ■ Responsive ■ Convenient ■ Innovative 3

Update to Explosive Gas

Monitoring Plan

UPPER SOUTHWEST ARKANSAS REGIONAL

SOLID WASTE MANAGEMENT DISTRICT LANDFILL

SOLID WASTE PERMIT 265-S1-R1 AFIN 31-00107

TERRACON PROJECT 35187259

August 31, 2018

Prepared for:

Upper Southwest Arkansas Regional Solid Waste Management District

P.O. Box 909 Nashville, AR 71852

Prepared by:

Terracon Consultants, Inc. Little Rock, Arkansas

TABLE OF CONTENTS

1.0 INTRODUCTION ................................................................................................... 1 1.1 Background.................................................................................................................. 1 1.2 Regulatory Requirements ............................................................................................ 2

1.2.1 Applicability ........................................................................................................... 2 1.2.2 Monitoring Program Requirements ....................................................................... 2 1.2.3 Gas Monitoring Plan ............................................................................................. 3 1.2.4 Elevated Level Detection Contingency Measures ................................................. 3 1.2.5 Definition ............................................................................................................... 4 1.2.6 Recordkeeping ...................................................................................................... 4

2.0 SITE CHARACTERIZATION AND TECHNICAL CONSIDERATIONS ................. 4 2.1 Technical Considerations ............................................................................................. 4 2.2 Landfill Configuration ................................................................................................... 5 2.3 Geologic and Geotechnical Considerations ................................................................. 6 2.4 Gas Migration Potential ................................................................................................ 6

3.0 LANDFILL GAS MONITORING PROGRAM ........................................................ 7 3.1 Landfill Gas Monitoring Probe Installation .................................................................... 7 3.2 Landfill Gas Monitoring Procedures ............................................................................. 9 3.3 Landfill Gas Monitoring Equipment .............................................................................. 9 3.4 Contingency Program .................................................................................................10 3.5 Record Keeping Requirements ...................................................................................10

Appendices Appendix A Explosive Gas Monitoring Probe Installation Report Appendix B Landfill Gas Monitoring Record Form FIGURES Figure 1 – Explosive Gas Plan Update Map

Update to Explosive Gas Monitoring Plan USARSWMD ■ Nashville, AR August 31, 2018 ■ Terracon Project No. 35187259

Responsive ■ Resourceful ■ Reliable 1

1.0 INTRODUCTION

This update to the Explosive Gas Monitoring Plan (Plan) for the Upper Southwest Arkansas Regional Solid Waste Management District (USARSWMD) Facility is in response to the Arkansas Department of Environmental Quality (ADEQ) Notice of Deficiency (NOD) letter dated July 26, 2018 concerning the review of the Solid Waste Major Modification update to the corresponding Solid Waste Permit 0265-S1-R1. ADEQ requested the Plan be updated due to the proposed cell expansion to the northeast and the relocation of a gas monitoring probe completed in July 2018.

1.1 Background

The USARSWMD operates a Class 1 Municipal Solid Waste Landfill (Landfill) under Solid Waste Permit Number 265-S1-R1 (Permit) issued by the ADEQ on August 27, 1993. The USARSWMD Landfill is located in a mined portion of the existing Boral Gypsum mine located north of Nashville, Arkansas. The Landfill is located west of Nathan Corinth Road, north of Arkansas State Highway 26 and east of the Union Pacific Railroad tracks. More specifically, the site lies in portions of Section 13 and 14 of Township 8 South and Range 27 West in Howard County. The Facility property consists of 348-acres with 40-acres (disposal area) currently used as a Class 1 landfill. The current Solid Waste Permit Modification states that the Landfill purchased a 43.5-acre tract of land northeast of the existing Class 1 Landfill with plans for an 18-acre (disposal area) cell expansion within the purchased tract. The Modification will increase the total permitted disposal area of 58-acres. The Landfill currently has an explosive gas monitoring system consisting of six gas monitoring probes (GP-3 will also be monitored but is not a compliance point) located outside the footprint of the Landfill and two monitoring locations within structures at the facility. During the December 13, 2016 monitoring event, the methane gas measurement at monitoring probe GP-3 was reported above 100% lower explosive limit (LEL). The measurements in the remaining monitoring probes were below regulatory limits for the facility. Landfill personnel were promptly notified of the exceedances. Contingency measures were taken in accordance with the landfills Gas Monitoring Plan. Terracon resampled GP-3 approximately two weeks following the initial exceedance to re-evaluate gas levels on site. The resample verified the exceedance. ADEQ was notified of the exceedance on January 10, 2017. In response to the exceedance, Terracon submitted an Explosive Gas Remediation Plan in February 2017 proposing to install a replacement explosive gas monitoring probe (GP-3R)



closer to the site boundary within the newly acquired 43.5-acre tract in the northeastern portion, which included the area previously covered by GP-3. GP-3R was installed in July 2018. The corresponding August 2018 Explosive Gas Probe Installation Report is provided in Appendix A. ADEQ issued a NOD correspondence letter dated July 26, 2018 concerning the Solid Waste Major Modification at the landfill requesting the Plan be updated due to the proposed cell expansion to the northeast and the relocation of gas monitoring probe GP-3R. Furthermore, at the request of ADEQ, Terracon proposes to install two additional gas monitoring probes, GP-7 and GP-8 (Figure 1), in conjunction with Cell 1 construction within the newly acquired 43.5-acre tract of land in the northeastern portion. Upon commencement of Cell 1 construction, a gas probe installation plan will be submitted to the ADEQ for approval.

1.2 Regulatory Requirements

The decomposition of solid waste (in particular household waste) produces methane, a potential landfill gas. The accumulation of methane gas in municipal solid waste landfill structures can result in fire and explosions that can injure or kill employees, disposal site customers, and occupants of nearby structures. EPA 40 CFR 258.23 and Arkansas Regulation 22 outline specific requirements for landfill gas monitoring corresponding to municipal solid waste landfills. The EPA handbook Solid Waste Disposal Facility Criteria: Technical Manual (EPA, 1993) includes additional information which provides assistance to landfill operators in achieving compliance with EPA 40 CFR 258.

1.2.1 Applicability

According to EPA 40 CFR 258.23 and Reg.22.415 of Arkansas Regulation 22, owners and/or operators of all MSWL units must ensure that:

(1) The concentration of methane gas generated by the facility does not exceed 25

percent of the lower explosive limit (LEL) for methane in facility structures

(excluding gas control or recovery system components); and

(2) The concentration of methane gas does not exceed the lower explosive limit for

methane at the facility property boundary.

1.2.2 Monitoring Program Requirements

In addition, owners or operators of all municipal solid waste landfill units must implement a routine methane monitoring program to ensure that the standards given above are met. The type and frequency of monitoring must be determined based on the following factors:

(1) Soil conditions;

(2) The hydrogeologic conditions surrounding the facility;



(3) The hydraulic conditions surrounding the facility; and

(4) The location of facility structures and property boundaries.

The minimum frequency for facility landfill gas monitoring shall be quarterly according to Regulation 22.415(b)(2).

1.2.3 Gas Monitoring Plan

The previous 2015 Plan was developed for ADEQ review and approval. The Plan included a preliminary action plan outlining immediate steps to be taken to protect human health and safety should methane gas levels exceed 100 percent of the LEL. The Plan included, but was not limited to the following information:

(1) Site specific factors affecting landfill gas migration; (2) Site conditions, landfill history, site design and construction practices; (3) Proximity and construction of on-site and off-site structures within 1/4 mile of the

limits of refuse; (4) Monitoring system design rationale and methodology that included detailed location

and design plans for in-soil gas probes; narrative description of rationale for location and depths of the gas probes, narrative and specifications for the construction of the probes and implementation of an approved monitoring routine;

(5) A description of the monitoring points in structures, and equipment locations; (6) Monitoring procedures including permanent probe monitoring, barhole probe

description, monitor calibration, recordkeeping, etc; and (7) Contingency plans in the case of monitoring results above the LEL, notification

procedures, remedial actions, etc.

1.2.4 Elevated Level Detection Contingency Measures

As aforementioned, during the December 2016 monitoring event, the methane gas measurement for monitoring probe GP-3 was reported above 100% LEL. The following contingency measures were followed and will continue to be followed if future exceedances occur on-site.

(1) Immediately take all necessary steps to ensure protection of human health and notify the ADEQ Director.

(2) Within seven days of detection, the owner/operator must place in the permanent operating record the methane gas levels detected and a description of the steps taken to protect human health.

(3) Within 60 days of detection, a remediation plan must be implemented for methane gas releases. The plan shall describe the nature and extent of the problem and the proposed remedy. This plan must be submitted to ADEQ for review and approval. Also, a copy of the plan must be retained in the permanent operating record.



(4) The Director may establish alternative schedules for demonstrating compliance with these regulations.

1.2.5 Definition

For purposes of this section, “lower explosive limit,” LEL, means the lowest percent by volume of a mixture of explosive gases in air that will propagate a flame at 25°C and atmospheric pressure.

1.2.6 Recordkeeping

Records shall be maintained in accordance with Reg.22.421 of Arkansas Regulation 22 to document compliance with this section.

2.0 SITE CHARACTERIZATION AND TECHNICAL CONSIDERATIONS

This section identifies the most likely locations for landfill gas accumulation and potential paths of gas migration associated with the Facility. These locations are identified based on the relative position of the area being considered in relation to the solid waste disposal area, soil conditions, hydraulic conditions, and hydrogeologic conditions.

2.1 Technical Considerations

A solid waste landfill can be conceptualized as a biochemical reactor, with solid waste and water as the major inputs, and landfill gas and leachate as the principal outputs. Gases found in MSWL units include ammonia, carbon dioxide, carbon monoxide, hydrogen, hydrogen sulfide, methane, nitrogen, and oxygen. TABLE 1 indicates the relative proportions of various landfill gases found in typical MSWL units. TABLE 1. TYPICAL CONSTITUENTS FOUND IN MSW LANDFILL GAS

COMPONENT PERCENT (dry volume basis)

Methane 45-60%

Carbon Dioxide 40-60%

Nitrogen 2-5%

Oxygen 0.1-1%

Sulfides 0-1%

Ammonia 0.1-1%

Hydrogen 0-0.2%

Carbon Monoxide 0-0.2%

Trace Constituents 0.01-0.6%

Reference: Integrated Solid Waste Management Engineering Principles and Management Issues (1993)



Methane and carbon dioxide are the principle gases produced from the anaerobic decomposition of the biodegradable organic waste components in municipal solid waste (MSW). As shown in TABLE 2, landfill gases are the result of microbial decomposition of solid waste. Methane gas, the principal component of natural gas, is generally the primary concern in evaluating landfills because it is odorless and highly combustible.

TABLE 2. STAGES OF LANDFILL GAS DEVELOPMENT

Phase I - Initial Adjustment Organic biodegradable components in MSW undergo microbial decomposition as they are placed in the landfill and soon after. Decomposition occurs under aerobic conditions because a certain amount of air is trapped in the landfill.

Phase II - Transition Phase Oxygen is depleted and anaerobic conditions begin to develop. As the landfill becomes anaerobic, nitrate and sulfate are often reduced to nitrogen gas and hydrogen sulfide.

Phase III - Acid Phase Microbial activity initiated in Phase II accelerates with the production of significant amounts of organic acids and lesser amounts of hydrogen gas.

Phase IV - Methane Fermentation Phase

A second group of microorganisms, which convert the acetic acid and hydrogen gas formed by the acid in the acid phase to methane and carbon dioxide, become more predominant. Both methane and acid form simultaneously.

Phase V - Maturation Phase Occurs after the readily available biodegradable organic material has been converted to methane and carbon dioxide in Phase IV. The rate of landfill gas generation significantly diminishes.

Reference: Integrated Solid Waste Management Engineering Principles and Management Issues (1993)

Methane gas is lighter than air and carbon dioxide is heavier than air. The gases will remain mixed and will migrate according to the density gradients between the landfill gas and the surrounding gases. This is also significantly affected by other gradients such as temperature and partial pressure. Generally, landfill gas will migrate along the path of least resistance. In a MSWL, the internal gas pressure is usually greater than atmospheric pressure and will cause landfill gas to be released by convective flow and diffusion (RE: Sharma and Lewis).

2.2 Landfill Configuration

The acreage corresponding to the USARSWMD Landfill consists of approximately a 348-acre tract owned by the USARSWMD. The USARSWMD is currently accepting waste in an area that has been accepting waste after the effective date of the Federal Regulations (April 9, 1994 for municipal landfills accepting less than 100 tons per day). Because all USARSWMD waste units can be considered “existing units” or “lateral expansions of existing units”, in terms of Subtitle D

applicability, the requirements of 40 CFR 258 Subpart C will apply to the USARSWMD Landfill during the life of the facility.



Currently, cell expansion is proposed in approximately 18-acres of the recently acquired 43.52-acre tract, bringing the total permitted Class I disposal area to approximately 58-acres. Due to the nature of the waste being disposed (putrescible), this area will most likely generate the majority of methane gas at the facility.

2.3 Geologic and Geotechnical Considerations

In order to consider the hydrogeologic conditions in the vicinity of the site, Terracon reviewed the “Supplemental Groundwater Study-Proposed Landfill Site – Howard County, Arkansas”

dated February 12, 1992. The report was prepared by Grubbs, Garner, and Hoskins (GGH) and summarizes the subsurface investigation conducted associated with the landfill in 1992. According to GGH, the landfill (present and future) is located within a “mined out portion” of the

existing Briar-Gypsum Mine located north of Nashville, Arkansas. GGH suggested the presence of fill (spoil) is present to depths of 15 to 20 feet below natural grade. The basal stratum was found to consist of very stiff reddish brown and gray clay. The project site is located within deposits of the Lower Cretaceous Trinity group. The Trinity group typically consists of mostly clay with some sand, gravel, limestone, gypsum and celestite. The limestone and gravel members are interbedded with clay and some sand. Three geologic units of significance exist in the vicinity of the MSWLF unit. These units are the Paluxy, the DeQueen limestone, and the Holly Creek. The Paluxy consists predominantly of variegated clays, cross-bedded sands and some gravel. The DeQueen consists of interbedded limestone and dark gray clay (shaley clay) with gypsum beds near the base. The underlying Holly Creek unit consists of variegated clays and cross-bedded sands with some gravel.

2.4 Gas Migration Potential

The clay residuum in the vicinity of the site is not conducive to liquid or gas migration. Because all expansion areas will be constructed with a composite liner system, the potential for gas migration from the site should be small. Throughout the useful life of a landfill, it is likely that any gas accumulation will seek the path of least resistance through the various layers of waste and daily cover to the land surface. The likely discharge area is in the uncovered working face of the landfill because this represents waste material that has experienced a lesser degree of compaction. The loose waste will provide the least resistance to gas movement in the landfill. However, there is some potential for localized gas build-up in waste layers entrapped by various layers of interim cover soil. In general, the probability for gas migration through the base liner system will increase during the "post closure" period, as the entire landfill will have received "final cover", thus restricting gas migration through the surface of the landfill. Anaerobic gas activity and associated pressure



build up will increase initially during the post closure period and taper off as the waste material decomposes and the landfill stabilizes. A gas collection and control system may be installed at the site to reduce the potential for subsurface migration of landfill gas from the waste disposal areas.

3.0 LANDFILL GAS MONITORING PROGRAM

The accumulation of methane in MSWL structures can potentially result in fire and explosions that can endanger employees, users of the disposal site, and occupants of nearby structures, or cause damage to landfill containment structures. In accordance with 40 CFR 258.23 and Arkansas Regulation 22, the following information outlines the procedures that will be implemented at the facility to help ensure that hazardous/dangerous levels of methane are not exceeded at the facility property boundary and/or in structures on site. In general, the Landfill Gas Monitoring Plan (LGMP) for the USARSWMD Landfill includes the following:

(1) Quarterly monitoring for landfill related landfill gas in probes and landfill structures (methane);

(2) Immediate steps are to be taken to protect human health in the event of methane gas levels exceeding 25% of the LEL in the facility structures and/or the concentration of methane gas exceeds the LEL of methane at the facility property boundary (Reg.22.415 (d));

(3) Immediate notification of the ADEQ if methane levels exceed 25% of the LEL in facility structures or the LEL at any methane monitoring probes installed at the property boundary; (Reg.22.415 (d)).

(4) Within 7 days of detection, a letter will be submitted to the ADEQ summarizing the results and the emergency response action taken. A copy of the letter will be retained in the facility permanent operating record. The contingency plan, as outlined in later sections will be immediately implemented.

(5) Within 60 days of detection, the facility will implement a corrective action plan for the methane gas migration, notify the ADEQ, and place a copy of the corrective action plan in the facility permanent operating record. The plan shall describe the nature and extent of the problem and the proposed remedy.

Regular quarterly landfill gas monitoring has been performed at the USARSWMD Landfill and will continue throughout the active life of the facility and during the post closure period.

3.1 Landfill Gas Monitoring Probe Installation

In August 2015, six (6) gas monitoring probes, designated GP-1, GP-2, GP-3, GP-4, GP-5, and GP-6 were installed at the Facility in order to adequately monitor the property boundary. The probes provide data for evaluating potential landfill gas migration beyond the landfill refuse and



near the property boundary, and to document whether landfill gas is currently migrating off the property to surrounding structures. The December 2016 monitoring event indicated that monitoring probe GP-3 was above the 100% LEL. Terracon subsequently resampled GP-3 approximately two weeks following the initial exceedance to re-evaluate the on-site gas levels. The resample verified the exceedance, and ADEQ was notified. In response to the exceedance, Terracon submitted an Explosive Gas Remediation Plan in February 2017, which proposed the installation of a replacement probe. The remediation plan was approved by the ADEQ in a letter dated March 6, 2017, and the replacement gas probe, GP-3R, was installed in July 2018. GP-3R is located along the newly acquired 43.5-acre tract in the northeastern portion and includes the area previously covered by GP-3. The corresponding August 2018 Explosive Gas Monitoring Probe Installation Report is provided in Appendix A. The gas probes were constructed as follows:

• Installation of approximately 15 to 20 feet of 1-inch diameter, 3/16-inch slotted Schedule 40 PVC riser with an approximate 1-inch bottom slip cap;

• The borehole around the PVC riser was filled with pea gravel to 2 feet bgs and then

topped with 10-20 silica sand to 1.5 feet bgs. Bentonite plug was used to create a seal above the granular material, filling the borehole to the ground surface level. This method ensures that the granular material is sealed below ground level but completely covers the screened interval of the gas probe riser.

• Surface completion of the gas probes consisted of a monument-type protective cover of

galvanized steel and a concrete pad. A reducing bushing (PVC 1-inch male end- x 3/8-inch female NPT) and a 3/8-inch ball valve with a 3/8-inch king nipple (for quick air hose connection) was placed onto the 1-inch PVC riser on each of the new explosive gas monitoring probes.

The gas monitoring probes were installed to a depth ranging from 10 to 20 feet below ground surface, and were constructed of 1” diameter Schedule 40 PVC above the saturated zone. The approximate locations of the gas monitoring probes are shown in FIGURE 1.

As aforementioned, at the request of ADEQ, Terracon proposes to install two additional gas monitoring probes, GP-7 and GP-8 (Figure 1), in conjunction with Cell 1 construction within the newly acquired 43.5-acre tract of land in the northeastern portion. Upon commencement of Cell 1 construction, a gas probe installation plan will be submitted to the ADEQ for approval.



3.2 Landfill Gas Monitoring Procedures

To demonstrate compliance with the requirements of 40 CFR 258.23, and Arkansas Regulation

22, the facility routinely monitors air quality inside the entrance office and other facility structures where methane gas could potentially accumulate. The person conducting the monitoring is trained in the proper use of the gas monitoring equipment, including calibration procedures. Prior to performing each quarterly landfill gas monitoring event, a qualified operator calibrates the methane detector and record the applicable weather conditions. Monitoring within facility structures consists of recording the concentration of methane (in % LEL) in each room of the facility utilizing an explosive gas analyzer calibrated to methane. When possible, readings are taken in enclosed areas, near electrical outlets, or floor drains, which could potentially be sites for landfill gas migration into the structure. At each location, the operator will measure the time, methane (% LEL), and oxygen (%). Any detected readings will be recorded for each location in each room. If no methane is detected in the room, a “non-detect (ND)” will be entered for that room on the landfill gas record form. In the event a detection occurs, a no-smoking policy will be strictly enforced within the facility structure. Routine sampling procedures are exercised at the six gas monitoring probe locations, and include at least the following procedures:

••• Record date, weather conditions, and monitoring equipment operator; ••• Calibrate explosive gas analyzer to methane and oxygen; ••• Inspect and record integrity of gas probe; ••• Unlock padlocks and remove protective hood; ••• Open well or valve and allow well sufficient time to equilibrate; ••• Place explosive gas analyzer on probe opening or place the end of the meter’s input

tube at least 18” below the top of casing and record gas concentration in % LEL and %

oxygen; ••• Measure gas and oxygen concentrations for at least 1 minute; ••• Close well opening once all measurements are completed; and ••• Detach explosive gas analyzer and replace protective hood casing over gas probe and

secure casing with padlocks.

3.3 Landfill Gas Monitoring Equipment

Landfill gas measurements are collected at each probe with a gas monitoring instrument (Landtec GEM 2000+ or equivalent). The instrument records the concentration of methane in “percent LEL”. The instrument is calibrated to methane prior to each monitoring event as outlined in the equipment manufacturer's literature.



3.4 Contingency Program

If a methane concentration exceeds 25% of the LEL in the buildings or 100% of the LEL (50,000 ppm or 5% in air) at the specified monitoring locations, the ADEQ will be notified and the following steps will be taken:

(1) The surrounding area corresponding to the monitoring point that indicates an explosive hazard will be evacuated and flagged with warning tape with the writing "Explosive Danger" clearly visible in order to protect human health and safety. The outer extremities of the "exclusion zone" will be defined by taking surface readings with the portable gas monitor. If there are no concentrations above 25% LEL at the surface in the vicinity of the monitoring location, then the exclusion zone tape will be flagged in a 10 foot radius around the location in question. No one will be allowed in the "Explosive Danger" area without prior approval from the landfill supervisor until corrective measures have been taken and the area is considered "safe".

(2) Any monitoring points with readings in excess of the established criteria (25% LEL in

buildings and 100% LEL at the property boundary) will be monitored again on an hourly basis. This process will continue until either (A) Three consecutive readings below the criteria are recorded, or (B) Three consecutive readings above the criteria are recorded. If scenario "(A)" takes place, the monitoring point will be checked again the following day, and an explanation of the possible reason for the initial excessive reading will be placed in the facility permanent operating record (i.e., equipment failure, etc.). If scenario "(B)" occurs, the facility will proceed to step "3" as described below and the ADEQ will be notified of the potential hazard within 7 days.

(3) If it is determined that an "explosive hazard" exists at any of the locations described

above, a corrective action plan will be submitted to the ADEQ within 60 days which will include steps that will be implemented to reduce or eliminate excessive gas buildup within the landfill unit and related potential migration to areas that could pose danger to human health and the environment.

3.5 Record Keeping Requirements

This Plan and all correspondence shall be retained as part of the facility's permanent operating record. All quarterly gas monitoring reports will also be maintained in the facility's permanent operating record. All information and records associated with the Landfill Gas Monitoring Program will be available for review, and will be submitted to the ADEQ as requested. All monitoring results will be recorded and documented on a Landfill Gas Monitoring Record Form, which is provided in APPENDIX B.

APPENDIX A

Explosive Gas Monitoring Probe

Installation Report

UPPER SOUTHWEST REGIONAL

SOLID WASTE MANAGEMENT DISTRICT LANDFILL

SOLID WASTE PERMIT 265-S1-R1 AFIN 31-00107


August 23, 2018

Prepared for: Upper Southwest Regional

Solid Waste Management District P.O. Box 909

Nashville, AR 71852

Prepared by: Terracon Consultants, Inc.

Little Rock, Arkansas

TABLE OF CONTENTS

Page

1.0 INTRODUCTION ................................................................................................... 1 1.1 Site Location ............................................................................................... 1 2.0 EXPLOSIVE GAS MONITORING PROBE INSTALLATION ................................ 1 2.1 Gas Monitoring Probe Installation .............................................................. 1 APPENDICIES

FIGURES

FIGURE 1 SITE LOCATION MAP FIGURE 2 GAS MONITORING PROBE LOCATION MAP

APPENDIX A

SOIL BORING LOG APPENDIX B

GAS PROBE CONSTRUCTION DIAGRAM


EXPLOSIVE GAS MONITORING PROBE INSTALLATION REPORT UPPER SW REGIONAL SOLID WASTE MANAGEMENT DISTRICT

NASHVILLE, ARKANSAS

ADEQ SOLID WASTE PERMIT 265-S1-R1


1.0 INTRODUCTION

The Upper Southwest Regional Solid Waste Management District (USWRSWMD) operates a Class 1 Municipal Solid Waste Landfill (Landfill) under Solid Waste Permit Number 265-S1-R1 (Permit) issued by the Arkansas Department of Environmental Quality (ADEQ) on August 27, 1993. With the acquisition of additional acreage for expansion of the USWRSWMD landfill and in accordance with the March 6, 2017 approved Explosive Gas Remediation Plan and Terracon’s response to Notice of Deficiencies letter dated June 20, 2018 to the

Arkansas Department of Environmental Quality (ADEQ). Terracon installed Gas Monitoring Probe GP-3R on July 19, 2018. The following report provides Gas Probe installation activities. 1.1 SITE LOCATION

The USWRSWMD Landfill is located in a mined-out portion of the existing Boral Gypsum mine located north of Nashville, Arkansas. FIGURE 1 displays the general Landfill site location. The Landfill is located west of Nathan Corinth Road, north of Arkansas State Highway 26 and east of the Union Pacific Railroad tracks. More specifically, the site lies in portions of Section 13 and 14 of Township 8 South and Range 27 West in Howard County. The permitted acreage corresponding to the Landfill consists of approximately 125 acres.

2.0 EXPLOSIVE GAS MONITORING PROBE INSTALLATION

2.1 GAS MONITORING PROBE INSTALLATION

The facility installed one (1) gas monitoring probe, designated GP-3R in accordance with the Explosive Gas Monitoring Plan dated March 6, 2017. The probe was installed to provide data for evaluating potential landfill gas migration beyond the landfill refuse and near the property boundary. The gas probes at the facility are utilized to document whether landfill gas is currently migrating off the property to surrounding structures. The probe was drilled by Anderson Engineering Consultants, Inc. with a CME 55, equipped

Explosive Gas Monitroing Probe Installation Report UPSWRSWMD – Class 1 Landfill ■ Nashville, AR August 23, 2018 ■ Terracon Project No. 35187198


with 6.25-inch flight augers. The gas monitoring probe was installed to a depth of 17 feet below ground surface. The probe was constructed of 1” diameter Schedule 40 PVC and installed above the saturated zone. FIGURE 2 shows the general location of GP-3R. The gas probe was constructed as follows:

• Installation of 20 feet of 1-inch diameter, Schedule 40 PVC riser with a screened interval from the bottom of the bore hole to approximately 3 feet below ground surface and an approximate 1-inch bottom cap;

• The borehole around the PVC riser was filled with pea gravel to 2 feet bgs and

then topped with 10-20 silica sand to 1.5 feet bgs. Bentonite plug was used to create a seal above the granular material, filling the borehole to the ground surface level. This method insures that the granular material is sealed below ground level but completely covers the screened interval of the gas probe riser.

• Surface completion of the gas probes consist of a monument-type protective

cover of galvanized steel and a concrete pad. A reducing bushing (PVC 1-inch male end- x 3/8-inch female NPT) and a 3/8-inch ball valve with a 3/8-inch king nipple (for quick air hose connection) was placed onto the 1-inch PVC riser on each of the new explosive gas monitoring probes.

The total depth of the probe is 17 feet below ground surface (bgs). The Site Location Map, Location of Gas Monitoring Probe GP-3R, Soil Boring Log, and Gas Monitoring Probe Construction Diagram are located in the APPENDICIES.

APPENDICIES

FIGURES

SITE

1

1000090008000

1

6000

1000

0

5000 7000

2000

2

4000

0

0

3000

.5

1000

1

1000

0 2000

.5

1000

1

KILOMETERS

METERS

MILES

SCALE 1:24 000

NATIONAL GEODETIC VERTICAL DATUM OF 1929

7.5 MINUTE SERIES (TOPOGRAPHIC)Project Mngr:

Approved By:

Checked By:

Drawn By:

Project No.

Scale:

Date:

File No.Consulting Engineers and Scientists

FIG. No.

25809 I-30 SOUTH BRYANT, AR 72022FAX. (501) 847-9210PH. (501) 847-9292

CONTOUR INTERVAL FEET

N

NATHANQUADRANGLE

1970

PTG

PTG

DGJ

DGJ

061-001-35157138

AS SHOWN

001

8/30/2017

SITE LOCATION MAP

1USWRSWMD SANITARY LANDFILL

UPPER SOUTHWEST REGIONAL SOLID WASTE MANAGEMENT DISTRICT

HOWARD COUNTY ARKANSAS

20

AutoCAD SHX Text

UNITED STATES - DEPARTMENT OF THE INTERIOR - GEOLOGICAL SURVEY

BM1

BM3

BM2

APPROX. PROPERTY BOUNDARY

43.52 ACRES

ACCESS ROAD

S-UD

N-UD

GGP-1

GGP-2

G GP-3

GGP-4

G GP-5

G GP-6

SEDIMENTATION POND

CLASS I LANDFILL

G GP-3R

DESIGNED BY:

SCALE:APPVD. BY:DRAWN BY:

DATE:

SHEET NO.:

JOB NO.

OF

BY DESCRIPTIONDATEREV.

ACAD NO.25809 I-30 SOUTH BRYANT, AR 72022FAX. (501) 847-9210PH. (501) 847-9292

Consulting Engineers and ScientistsUPPER SOUTHWEST REGIONAL SOLID WASTE MANAGEMENT DISTRICT

GAS MONITORING PROBE LOCATION MAP


QMBTLBQMB1" = 500'08/23/2018061-001-35187198003

FIGURE 2

USWRSWMD SANITARY LANDFILL

N

0

SCALE IN FEET

125 250 500

LEGEND:GAS MONITORING PROBEG

GP-1

NEW GAS MONITORING PROBEGGP-3R

APPENDIX A

SOIL BORING LOG

APPENDIX B

GAS MONITORING PROBE CONSTRUCTION DIAGRAM

Granular Backfill MaterialRiser Diameter & MaterialScreen Diameter & MaterialDatum for Water Level Measurement

Drilling Method

Datum ElevationJob NumberJob Name

Northing

Terracon RepresentativeBorehole Diameter

Drilling Contractor

LocationWell Number

Installation DateSurface Elevation

GAS PROBE INSTALLATION RECORD

GAS PROBE INSTALLATION RECORD

25809 I-30 South BRYANT, AR. 72022FAX. (501) 847-9210PH. (501) 847-9292

Consulting Engineers and Scientists

EastingNA

2' bgs

7/19/2018

AutoCAD SHX Text

Solid Riser

AutoCAD SHX Text

Flush Joint

AutoCAD SHX Text

Granular Material

AutoCAD SHX Text

Depth to Top of

AutoCAD SHX Text

Silica Sand

AutoCAD SHX Text

Bentonite Chips

AutoCAD SHX Text

Granular Material (Pea Gravel)

AutoCAD SHX Text

Granular Material

AutoCAD SHX Text

Ground Surface

AutoCAD SHX Text

and Bottom Cap.

AutoCAD SHX Text

PROJECT NUMBER:

AutoCAD SHX Text

WELL NUMBER:

AutoCAD SHX Text

DRAWING NUMBER:

AutoCAD SHX Text

(Not to Scale)

AutoCAD SHX Text

Screen

AutoCAD SHX Text

CHECKED BY:

AutoCAD SHX Text

Length of Solid

AutoCAD SHX Text

riser:

AutoCAD SHX Text

Well Protector

AutoCAD SHX Text

Valve

AutoCAD SHX Text

Lockable Casing

AutoCAD SHX Text

Stickup:

AutoCAD SHX Text

Total Depth of

AutoCAD SHX Text

Gas Probe:

AutoCAD SHX Text

Length of Screen

AutoCAD SHX Text

from TOC

AutoCAD SHX Text

Concrete Pad

AutoCAD SHX Text

Bollard Post

AutoCAD SHX Text

Cap

AutoCAD SHX Text

6" Silica Sand

AutoCAD SHX Text

USWRSWMD GAS PROBE INSTALLATION

AutoCAD SHX Text

GP-3R

AutoCAD SHX Text

35187198

AutoCAD SHX Text

USWRSWMD CLASS I LANDFILL

AutoCAD SHX Text

NA

AutoCAD SHX Text

NA

AutoCAD SHX Text

T.O.C.

AutoCAD SHX Text

2" PVC

AutoCAD SHX Text

NA

AutoCAD SHX Text

1" SCHEDULE 40 PVC

AutoCAD SHX Text

6.25"

AutoCAD SHX Text

PEA GRAVEL

AutoCAD SHX Text

QUIN BABER IV

AutoCAD SHX Text

SOLID FLIGHT AUGERS

AutoCAD SHX Text

ANDERSON ENGINEERING

AutoCAD SHX Text

3'

AutoCAD SHX Text

3'

AutoCAD SHX Text

20'

AutoCAD SHX Text

14'

AutoCAD SHX Text

061-001-35187198

AutoCAD SHX Text

GP-3R

AutoCAD SHX Text

002

AutoCAD SHX Text

QMB

APPENDIX B

UPPER SOUTHWEST RSWMD LANDFILL

Explosive Gas Monitoring Record

DATE:

MONITORING EQUIPMENT USED:

MONITORING CONDUCTED BY: m

WEATHER CONDITIONS (General):

Monitoring

Point

Performance

Criteria

% LEL

Methane

% Methane O2 Level Time

GP-1 100% LEL

GP-2 100% LEL

GP-3 100% LEL

GP-3R 100% LEL

GP-4 100% LEL

GP-5 100% LEL

GP-6 100% LEL

Bailer Facility 25% LEL

Office Building 25% LEL

*Values in BOLD exceed Lower Explosive Limit (LEL)

FIGURE 1

BM1

BM3

BM2

APPROX. PROPERTY BOUNDARY

43.52 ACRES

ACCESS ROAD

S-UD

N-UD

SEDIMENTATION POND

CLASS I LANDFILL

GGP-3R

GGP-3

GGP-2

GGP-1

GGP-6

G GP-5

GGP-4

PGP-7

PGP-8

DESIGNED BY:

SCALE:APPVD. BY:DRAWN BY:

DATE:

SHEET NO.:

JOB NO.

OF

BY DESCRIPTIONDATEREV.

ACAD NO.25809 I-30 SOUTH BRYANT, AR 72022FAX. (501) 847-9210PH. (501) 847-9292

Consulting Engineers and Scientists

UPPER SOUTHWEST REGIONAL SOLID WASTE MANAGEMENT DISTRICT

EXPLOSIVE GAS PLAN UPDATE


LMTPTGDGJAS SHOWN9/21/2018061-001-35177012004

FIGURE 1

USWRSWMD SANITARY LANDFILL

N

0

SCALE IN FEET

125 250 500

LEGEND:

GAS MONITORING PROBE

RELOCATED GAS MONITORING PROBE(JULY 2018)G

GP-3R

GGP-1

PROPOSED GAS MONITORING PROBELOCATIONSP

GP-7

MISC. REPAIRS (SUBSIDENCE, SETTLING, EROSION, ROADS, ETC.)ITEM QUANTITY UNIT UNIT PRICE AMOUNT

Labor (2 people x 8 hr/day x 2 days/yr) 32 Hours 15.00$ 480$ Equipment - Dozer 16 Hours 100.00$ 1,600$ - Dump Truck 16 Hours 60.00$ 960$ - Loader 16 Hours 65.00$ 1,040$ Misc. Materials and Services 1 LS 5,000.00$ 5,000$ TOTAL MISC. REPAIRS 9,080$

MAINTAIN & OPERATE LEACHATE COLLECTION SYSTEMITEM QUANTITY UNIT UNIT PRICE AMOUNT

Capital Cost of System ($150,000; Estimated Life = 30 years)Annual Maintenace and Repair (1/30 of Capital Cost) 5,000$ Leachate Pumping/Storage (Electrical Power) 50,000 gal 0.05$ 2,500$ Annual Transportation Costs 50,000 gal 0.05$ 2,500$ Annual Treatment Costs 50,000 gal 0.10$ 5,000$ TOTAL LEACHATE SYSTEM O&M 15,000$

MAINTAIN & OPERATE GROUNDWATER MONITORING SYSTEM

ITEM # WELLS UNIT COST/WELL AMOUNT

Capital Cost (12 wells at $5,000 = $60,000; Assume 30 year life)Annual Maintenance and Repair (1/30 of Capital Cost) 2,000$ Annual Sampling Cost (2/year) 12 Wells 750.00$ 9,000$ Annual Laboratory Analysis (2/year)+QA/QC 12 Wells 1,500.00$ 18,000$ Statistical Analysis (2/year) 12 Wells 1,000.00$ 12,000$ TOTAL ANNUAL GW MONITORING SYSTEM COSTS 41,000.00$

MAINTAIN & OPERATE GAS MONITORING SYSTEMITEM # PROBES UNIT COST/PROBE AMOUNT

Capital Cost of System (8 probes at $1,500 = $12,000; Assume 30 year life)Annual Maintenace and Repair (1/30 of Capital Cost) 400$ Sampling/Analysis Costs (4/year) 8 Probes 500.00$ 4,000$ TOTAL GAS MONITORING O&M 4,400$

TOTAL ANNUAL POST-CLOSURE CARE COST FOR PERIOD: 69,480$ TOTAL ESTIMATED POST-CLOSURE CARE COSTS FOR 30 - YEAR PERIOD: 2,084,400$

Post Closure Cost Inflation Adjustment

Year

2019202020212022202320242025

Notes:Inflation factor is based on the Implicit Price Deflator for the U.S. Gross National Product for the given year as providedon the Arkansas Department of Environmental website.

POST CLOSURE CARE COST ESTIMATE FOR FINANCIAL ASSURANCEUPPER SOUTHWEST ARKANSAS SOLID WASTE MANAGEMENT DISTRICT

YEARS 1-30 AFTER FINAL CLOSURECLASS 1 SOLID WASTE FACILITY

Implicit Price Deflator for Gross Domestic

ProductAdjusted Closure Cost Estimate

Upper Southwest Arkansas Regional Solid Permit Modification Application Waste Management District Class 1 Landfill Financial Assurance Criteria

Civil Engineering Associates, LLC 22-1 January 2018

22.0 FINANCIAL ASSURANCE CRITERIA

Section 22.432 of Arkansas Regulation 22 states that: (a) Applicants, permittees, owners or operators shall also refer to applicable provisions of

Chapter 11 Geotechnical and Hydrogeological Investigations, Chapter 12 Ground Water Monitoring and Corrective Action, Chapter 13 Closure and Post-Closure Care, and Chapter 14 Financial Assurance Criteria, for additional requirements.

Chapter 14 of Arkansas Regulation 22 outlines specific requirements for solid waste facilities associated with the establishment of financial assurance for Closure and Post Closure Care. Cost estimates have been developed for the Closure and Post Closure Care of the Upper Southwest Arkansas Regional Solid Waste Management District Class 1 Landfill facility. The cost estimates are based on the design, closure plan, post closure plan, and other information provided in this Permit Modification Application. The cost estimates are provided in APPENDIX 22-A. The cost (in 2018 dollars) to close the largest cell of the Class 1 facility (using a 3rd party contractor) is provided in APPENDIX 22-A. The amount of financial assurance required for closure to comply with the regulations is $3,617,316 which corresponds with the cost to close the facility at a worst case scenario (58 acres). The amount of financial assurance required for post closure is $416,880 (20% of the estimated total post-closure cost). The total amount of financial assurance required to comply with Arkansas Regulation 22 is $4,034,196. This estimate should be reviewed and adjusted (if needed) on an annual basis to consider inflation and/or changes to the facility Closure and Post Closure Plans.

Upper Southwest Arkansas Regional Solid Permit Modification Application Waste Management District Class 1 Landfill Financial Assurance Criteria

Civil Engineering Associates, LLC January 2018

APPENDIX 22-A CLOSURE AND POST CLOSURE COST ESTIMATES

ITEM QUANTITY UNIT UNIT PRICE AMOUNT

Surface Preparation 58 ACRES 500.00$ 29,000$

Compacted Clay Cover (18") 140,360 CY 4.00$ 561,440$

Synthetic Liner (40 mil VFPE Textured) 2,526,480 SF 0.45$ 1,136,916$

Geocomposite Drainage Layer 2,526,480 SF 0.50$ 1,263,240$

Vegetative Cover Layer (12") 93,573 CY 3.00$ 280,720$

Installation of Mid-Slope Berms and Let-downs 1 LS 50,000.00$ 50,000$

Seeding/Fertilizing/Mulching 58.0 AC 1,000.00$ 58,000$

Erosion Control 1 LS 15,000.00$ 15,000$

Preparation of Contract Documents 1 LS 30,000.00$ 30,000$

Quality Assurance/Control 1 LS 175,000.00$ 175,000$

Surveying 1 LS 10,000.00$ 10,000$

Certification and Final Report Preparation 1 LS 8,000.00$ 8,000$

TOTAL 3,617,316$

Notes: 1. All costs are in year 2018 dollars and should be updated on an annual basis to consider inflation and design changes (if any);2. The cost estimates are based on the cover system design provided in the facility Closure and Post Closure Care Plan prepared by Civil Engineering Associates, LLC dated January 2018.3. This estimate reflects the costs associated with closing all permitted areas (Approximately 58 Acres).

Closure Cost Inflation Adjustment

Year

2019202020212022202320242025

Notes:

Inflation factor is based on the Implicit Price Deflator for the U.S. Gross National Product for the given year as provided

on the Arkansas Department of Environmental website.

CLOSURE COST ESTIMATE FOR FINANCIAL ASSURANCEUPPER SOUTHWEST ARKANSAS REGIONAL

CLASS 1 SOLID WASTE FACILITY

Adjusted Closure Cost Estimate

SOLID WASTE MANAGEMENT DISTRICT


Product












Year

2019202020212022202320242025






1

Blue, Karen

To: Arjmandi, MasoudSubject: RE: Financial Assurance

From: Lance Powell [mailto:[email protected]] Sent: Tuesday, February 05, 2019 8:32 AM To: Arjmandi, Masoud Subject: Financial Assurance Masoud, I have attached the closure and post‐closure care cost estimates associated with the permit modification application that was submitted for the Upper Southwest Arkansas Regional Solid Waste Management District Class 1 Landfill. The cost estimates have been updated to consider inflation as you requested. Please let me know if you need anything additional. Lance Powell, P.E. Member CIVIL ENGINEERING ASSOCIATES, LLC 2114 East Matthews Avenue Jonesboro, Arkansas 72401 Phone: (870) 972‐5316 Fax: (870) 932‐0432 Mobile: (870) 243‐9400

ITEM QUANTITY UNIT UNIT PRICE AMOUNT

Surface Preparation 58 ACRES 500.00$ 29,000$

Compacted Clay Cover (18") 140,360 CY 4.00$ 561,440$

Synthetic Liner (40 mil VFPE Textured) 2,526,480 SF 0.45$ 1,136,916$

Geocomposite Drainage Layer 2,526,480 SF 0.50$ 1,263,240$

Vegetative Cover Layer (12") 93,573 CY 3.00$ 280,720$

Installation of Mid-Slope Berms and Let-downs 1 LS 50,000.00$ 50,000$

Seeding/Fertilizing/Mulching 58.0 AC 1,000.00$ 58,000$

Erosion Control 1 LS 15,000.00$ 15,000$

Preparation of Contract Documents 1 LS 30,000.00$ 30,000$

Quality Assurance/Control 1 LS 175,000.00$ 175,000$

Surveying 1 LS 10,000.00$ 10,000$

Certification and Final Report Preparation 1 LS 8,000.00$ 8,000$

TOTAL 3,617,316$

Notes: 1. All costs are in year 2018 dollars and should be updated on an annual basis to consider inflation and design changes (if any);2. The cost estimates are based on the cover system design provided in the facility Closure and Post Closure Care Plan prepared by Civil Engineering Associates, LLC dated January 2018.3. This estimate reflects the costs associated with closing all permitted areas (Approximately 58 Acres).

Closure Cost Inflation Adjustment

Year

2018201920202021202220232024

Notes:

Inflation factor is based on the Implicit Price Deflator for the U.S. Gross National Product for the given year as provided

on the Arkansas Department of Environmental website.



1.018 $3,682,427.69

CLOSURE COST ESTIMATE FOR FINANCIAL ASSURANCEUPPER SOUTHWEST ARKANSAS REGIONAL

CLASS 1 SOLID WASTE FACILITYSOLID WASTE MANAGEMENT DISTRICT












Year

2018201920202021202220232024


1.018 $2,121,919.20



