Request for Proposal

Date: November 14, 2017 Project Title: Inman Landfill - Post-Closure Care (PCC) Landfill Gas (LFG) management

control system optimization Primary Contact: John Rapp

Address: 1800 Continental Place, Mount Vernon, WA 98273 Phone: 360-416-1460 Email: johnr@co.skagit.wa.us

Secondary Contact: Samantha Clark Address: 1800 Continental Place, Mount Vernon, WA 98273

Phone: 360-416-1453 Email: sclark@co.skagit.wa.us

Submission Deadline: No later than 4:30 p.m. Friday December 15, 2017 to John Rapp or Samantha Clark

1. Introduction The Inman Landfill is located 7½ miles northwest of Mount Vernon in Skagit County, Washington (Figure 1). Skagit County Public Works operated the facility on 51 acres of County-owned and leased property. The landfill accepted County-generated municipal waste, demolition debris, and special incinerator ash. In order to control off-site migration of (LFG), odor, and gas buildup under the cover system, an active LFG collection system was installed during PCC construction. The system was built in stages to accommodate the phased closures in 1993 and 1994. The LFG management control system site layout is shown on Figure 2. LFG management at Inman Landfill utilizes an active gas extraction system consisting of 20 vertical wells (W-1 thru W-20), horizontal trenches with perforated pipe (T-1, -2, -4, -6, -10, -11, and -13), manifold collection system, and blower/flare facility. The blower provides a negative pressure within the gas collection system (i.e., wells and trenches), drawing gas into the system and conveying it to the flare where it is combusted. The motor blower/flare facility location is adjacent to the leachate pond. Methane migration is monitored under Subtitle D of the Municipal Solid Waste Landfill regulations to determine whether off-site migration of methane is occurring at levels that may be potentially explosive. Quarterly monitoring is performed at monitoring points around the perimeter of the landfill (Figure 2). 2. Scope of Work Skagit County is seeking proposals that, with the assistance of county personnel, evaluate the current LFG management system, and how the system can be modified, optimized, or eliminated, while still protecting human health and the environment. The LFG management system has operated since approximately 1992, and sporadically since approximately 2014. County personnel have monitored methane, carbon dioxide and oxygen levels at each extraction well location with a GEM 2000 landfill gas meter. In order to achieve a level of combustible methane that is sufficient to ignite and maintain the flare valves associated with underperforming extraction wells (wells with methane levels below a threshold value of 30-40% methane) have been closed. Presently, there are approximately 6 open LFG extraction wells. However, the LFG management system is underperforming due to low subsurface methane concentrations, aging piping systems, and/or a combination of these factors.

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The scope of work would include: evaluating the current LFG management system and whether the initial designed capacity is still appropriate based on the current concentrations of landfill gas being generated at the site; modifying the current active system; implementing a targeted active system; and/or implementing some type of passive system that targets areas with elevated levels of methane.

3. Project Budget Not to exceed $10,000.

4. Proposal Submission Requirements Please include the following in your proposal:

• Methodology and technical approach to the project • Firm and individual experience with similar projects • Key personnel • Proposed project schedule • Proposed project cost • Two (2) references • MBE/WBE/DBE certifications, if any • Primary office location where work would be conducted • Physical address, telephone number and email address

There are no formatting requirements for submissions, however submissions should be 20 pages or less, and 10MB or less in file size. Electronic delivery of proposals is welcome; hard copies are not necessary. 5. Selection Criteria

• Methodology and technical approach to the project (30) • Qualifications of proposer and proposer’s personnel (25) • Experience with similar projects/references (20) • Project schedule (15) • Budget (10)

Total maximum scoring points: 100 If interested in the project, please return the proposal no later than 4:30 p.m. Friday December 15, 2017 to John Rapp or Samantha Clark. If your response is not received by the aforementioned date, your company will not be considered in the review process.

Skagit

*Locations are approximate.

1 40

Miles

LegendFigure 1. Inman Landfill

Location MapParcel boundary*

Landfill boundary*

Inman Landfill

2

South StormwaterIn�ltration Basin

StormwaterDetention Pond

North StormwaterIn�ltration Basin

Leachate Pond

Blowers

Condensate Collection Tank

WestStormwaterIn�ltration

Basin

PHASE 1

PHASE 2

ASH CELL

PHASE 1

Flare

Site Entrance

Site Entrance

PS#1

Wet Well (Former PS#2)

Burn Pile Location

W7 W6

T13

T11

W5

W17

T10

W4

W8

T6

W3

W16T4

W2

T2 W15

W10 W9

T1

W1

W11

W20

W12 W14

W13

LC01W18 W19 LC02

Figure 1-2. Collection System Layout

Legend

Groundwater Monitoring Well

Gas Probe

Gas Probe/Monitoring Well Combination

Gas Collection Well or Trench

Above Ground LFG Pipe

Buried LFG Pipe

Landfill Boundary

Fence

2001000SCALE IN FEET

B-2

B-1

B-4

B-13B-12

B-3

B-8GDW-5

GDW-2

GDW-1

B-6

B-5

B-7

B-9

B-10

B-11

GP-6

GP-7

1-3

X

X

X

XXX

X

XXXX

X

2 foot contour interval