Montrose Environmental
1631 East Saint Andrews Plaza
Santa Ana, CA 92705
t 714.919.6500
June 15, 2022
James Velez-Conway
Senior Sustainability Analyst
City of Santa Monica
2500 Michigan Ave, Bldg. 4
Santa Monica, CA 90404
RE: Proposal for New LFG Extraction Wells and System Upgrades Needed at the Landfill City of Santa Monica Corporate Yard
2500 Michigan Avenue, Santa Monica, California
Dear Mr. Velez-Conway,
Montrose Environmental Solutions (Montrose) is pleased to submit this proposal for recommended upgrades to the landfill gas (LFG) control and treatment system for the City of Santa Monica landfill site located at 2500 Michigan Avenue within the City of Santa Monica.
This proposal has been prepared to estimate the permitting, preparation, installation, repair, replacement, and related reporting costs for needed upgrades at the site to ensure proper system operation and prevent future compliance issues.
The bulk of these costs are related to the installation of two new dual-completion vertical landfill gas extraction well (LFG-11 and LFG-12). The installation these new LFG extraction wells has been determined to be necessary to control the elevated methane that has been detected in the planter boxes in the central parking lot area and also at probes PP-14 and PP-5R (see attached map). Currently the landfill is out-of-compliance due to the methane concentration at PP-14.
LFG Extraction Wells Installation
Prior to field activities engineered plans showing the LFG extraction well, horizontal trench, and lateral piping connection to the existing LFG header will be submitted to the Santa Monica Department of Public Works (SMDPW) for approval. An application to modify the number of vertical LFG extraction wells listed on the Permit To Operate F59249 will also be submitted to the South Coast Air Quality Management District (SCAQMD) along with these plans.
Proposal for LFG Extraction Wells and System Upgrades Needed at the Landfill City of Santa Monica Corporate Yard June 15, 2022
2500 Michigan Ave, Santa Monica Page 2
An engineer will also perform calculations to determine the friction loss of the LFG piping at the site to ensure that the new wells will receive proper vacuum. This will also help to determine the adequacy of the current equipment and piping to handle the current and additional LFG flow.
Two weeks prior to scheduling field activities, the proposed locations will be marked with white paint and Underground Service Alert (USA) will be notified to check for underground utilities in the vicinity of the proposed excavation and drilling locations. Due to the knowledge of subsurface utilities in the proposed area of drilling and trenching, a geophysical survey may not be required. However, if it is requested it can be added to the proposal and would utilize electromagnetic and ground penetrating radar to locate the underground utility lines and identify subsurface features and structures.
A Site Specific Health & Safety Plan covering the drilling, excavation, and piping activities will be prepared. The Enforcement Agent (LEA) from the LACDPH and the City of Santa Monica will be notified prior to commencing any field activities. The LEA may require that the Workplan detailing the installation activities be submitted for review and approval, prior to scheduling field work.
Each day, before commencing field activities, a daily “tailgate” health and safety meeting will be held with Montrose personnel and contracted employees. The work area(s) will be clearly demarcated using caution tape, orange cones, and other safety barriers. If it is necessary to leave any open borings or trenches overnight, the areas will be covered securely with steel plates or similar.
A C-57 drilling contractor will be retained to provide soil boring and well installation services using a CME-85 or CME-95 hollow stem auger drill rig. Prior to drilling a hand auger will be used to clear the borehole location down five feet to ensure there are no signs of utilities. The drilling augers will then be advanced and subsurface soil and waste materials logged every five feet by a Geologist in Training under the oversight of a Professional Geologist to the total depth of the boring.
Each well will have screens installed between approximately 25 to 40 feet deep (the deep zone) and between 8 to 12 feet deep (the shallow zone). However, these zones may be modified slightly due to the subsurface conditions encountered. The well screens should ideally be placed in a zone of sandy fill or more permeable waste and not in a zone of ash or clayey fill, which is less permeable. The proposed LFG extraction wells will be constructed similar to the example Landfill Gas Extraction Well, which is attached to this proposal as Figure 2.
Proposal for LFG Extraction Wells and System Upgrades Needed at the Landfill City of Santa Monica Corporate Yard June 15, 2022
2500 Michigan Ave, Santa Monica Page 3
The trenching to connect the well LFG-11 to the existing header near well LFG-9 is conservatively estimated to be approximately 150 feet long (Figure 1). This will be in an area of traffic, so traffic rated trench plates and coordination with the site will be required. The well and trench area will be marked off with Caution Tape and Orange Cones or similar Safety Supplies. The well should be installed in one day and the trenching contractors are expected to take approximately 9 days to excavate from the well head to the header, lay the pipe, and backfill and repave the trench.
The trench to connect well LFG-12 to the existing header is approximately 40 feet long and should take 3 days to excavate, lay the pipe, and backfill. This well and trench are located in the “Hanson Yard” construction area, which will be paved in future. Traffic rated metal plates will be laid across the trench after it is backfilled.
Soil and waste cuttings generated during the vertical well installations will be contained in DOTapproved 55-gallon steel drums. The soil drums will be appropriately labeled and stored in a pre-selected designated location at the Santa Monica City Yard Site pending profiling results. A composite sample will be collected for each well boring and analyzed by a State-Certified analytical laboratory for hazardous contaminants to determine the appropriate handling and disposal. Once profiled, the soil drums will be picked up by a licensed transporter and taken to a certified disposal/recycling facility under manifest. The waste management cost estimate includes the cost to transport and dispose of non-hazardous waste. It is anticipated that the soils cuttings from the borings and the decontamination waste water from the well installations will be non-hazardous. It is also expected that the surface fill soils excavated from the trenching, will be reused to backfill the trench and will not require transport offsite.
Montrose will prepare a final report describing the installation activities and including the well and trench construction details, the subsurface lithology encountered, the lab data, the Health & Safety monitoring data, the permits obtained, and all other documents related to the well installation.
The costs to complete the installation work with prevailing wage are outlined in the following table. The estimate below includes all taxes and markup. The subcontractor quotes for the well installation, trench and piping installation, laboratory analysis, and drum disposal, are available upon request.
Proposal for LFG Extraction Wells and System Upgrades Needed at the Landfill City of Santa Monica Corporate Yard June 15, 2022
2500 Michigan Ave, Santa Monica Page 4
TASKS COST
1 – Install vertical LFG-12 and trench including permits, plans, labor, travel, FID monitoring, all materials and equipment, waste management and final report
$67,000
2 – Install vertical LFG-11 and trench including permits, plans, labor, travel, FID monitoring, all materials and equipment, waste management and final report
$120,00
10% Contingency for unexpected delays, geophysical survey, fuel & parts price increases
$18,700
Total Cost: $205,700
New Blower and Motor Installation
The current 20 hp blower and motor that provide vacuum to the LFG extraction wells are over 20 years old. The “backup” blower is also over 20 years old and had parts removed to support the operating blower. If the active blower were to have mechanical issues, the parts would be very hard to obtain due to its age and the landfill would be left without any LFG control capability. Therefore, Montrose highly recommends installing a new 20 hp blower and motor and making the current operating blower the “backup” blower. The new blower will also be able to provide greater vacuum to the expanded LFG control system, which will help provide greater control of the landfill gas at the site.
The costs to transport and install the blower and hook it up to the existing piping and electrical systems including prevailing wage are included in the following table. The estimate below includes all taxes and markup.
TASK COST
3 – Install 20 hp blower & motor including obtaining permits, labor, travel, all materials and equipment.
$50,000
Rewire LFG System Control Panel to Improve Functionality & Restore Remote Notification Due to the age of the control panel, some of the functionality has been lost. There used to be an alarm “Call out system” in the past, but currently there is no functioning notification system to alert Montrose or the City of problems at the site. If there is a power out, or the compressor shuts down, or a condensate tank overflows, etc. it may be up to 7 days before Montrose returns to the site and discovers the problem during the bi-weekly inspections. Montrose obtained a quote from Bravi Electric to install a new call-out Alarm system, upgrade the control Proposal for LFG Extraction Wells and System Upgrades Needed at the Landfill City of Santa Monica Corporate Yard June 15, 2022
2500 Michigan Ave, Santa Monica Page 5
panel, add a high liquid level sensor to the entrainment tank, and add emergency shut offs to prevent the condensate tank from overflowing.
The cost including prevailing wage, permitting, taxes and markup are listed below.
TASK COST
4 – Install a new Alarm Call Out system, upgrade control panel and run new conduit and wires, install float sensor on entrainment tank and wire high level sensors to control panel. Includes obtaining permits, labor, travel, all materials and equipment.
$40,000
Raise Probes and Header Access Vault in Hanson Yard Construction Area Due to increased grades in the Hanson Yard construction area, probe clusters PP-14 and PP-5R will need to have the casings extended on 6 probes and the protective boxes dug out and raised for future accessibility. The protective box on the header access vault will also need to be raised.
The cost below includes the materials, labor, taxes and markup.
TASKS COST
5 – Raise probes PP-5R, PP-14 and header access vault for accessibility $4,300 The Not-To-Exceed cost for these five tasks is $300,000.
Montrose appreciates the opportunity to be of service. If you have any questions or require additional information, please do not hesitate to call us at (714) 919-6530.
Respectfully submitted,
Kris Kern Margaret Patrick
Project Geologist, G.I.T. Project Manager, P.G.
Attachments: Figure 1 – Aerial Photo with Approximate Proposed Well & Trench locations Example of Dual Nested Landfill Gas Extraction Wells
WELL CONSTRUCTION DETAILS
WELL NUMBER: Proposed LFG-11 and LFG-12
WELL TYPE: Dual Nested Landfill Gas Extraction Well
LID ELEVATION (NGVD29):
CASING ELEVATION (NGVD29):
Large Traffic Rated Well Box DRILLING SUMMARY
Ground Surface INSTALLATION DATE: TBA
Concrete DRILLING COMPANY: TBA
Well Heads
3 feet 3 feet DRILLING RIG TYPE: Hollow Stem Auger
Clean Soil/Native + 5% bentonite 4 feet 4 feet
TOTAL DEPTH DRILLED:
6 feet 6 feet
Transition (#3 Sand or clean soil) 7 feet Blank Casing
Top of Screen 8 feet CONSTRUCTION DETAILS
BOREHOLE DIAMETER: ~18 inches
1/4 inch pea gravel filter pack Shallow Deep
0.10 inch V-wire Screen TOTAL WELL DEPTH: ~12 feet ~35 to 40 feet BLANK CASING TYPE:
Bottom of shallow well screen 12 feet Shallow Deep
13 feet 13 feet BLANK CASING DIAMETER: 2-inch 6" screen 17 feet Shallow Deep
Clean Soil/Native + 5% bentonite 19 feet TOTAL BLANK CASING LENGTH: 8 ft. 25 ft.
Bentonite Seal
22 feet SCREEN TYPE: Sch 80, V-wire screen
Transition (#3 Sand or clean soil) 23 feet Shallow Deep 25 feet SCREEN SLOT SIZE: 0.10 inch 0.20 inch
Top of Screen Shallow Deep
SCREEN LENGTH: ~ 4 feet ~ 15 feet
SUMP LENGTH:
0.20 inch V-wire Screen
PROTECTIVE CASING STICKUP:
3/4 inch washed gravel filter pack Annulus Backfill MATERIAL:
SEAL MATERIAL Medium Bentonite Chips
Shallow Deep
FILTER PACK MATERIAL: 1/4 pea gravel 3/4 inch gravel
COMMENTS:
~40 feet
~ 41 feet
Sch 80 PVC
~18-inch minimum borehole
Clean Soil/Native compacted in 2 foot
lifts
~35 to 41 feet
Clean soil/Native mixed with 5% bentonite;
compacted soil backfilled in 2 foot lifts
* Drawing Not to Scale
Total Depth of Boring
Flush Threaded End Cap
Bentonite Seal
--
No Sump
1-inch berm to prevent
flooding