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HomeMy WebLinkAbout21- Task Order - Tetra Tech - Remediation Systems Operation & Maintenance - Landfill FY22 Tetra Tech 851 Bridger Drive, Suite 6; Bozeman, MT 59715 Tel 406.582.8780 Fax 406.582.8790 tetratech.com TASK ORDER 2021-2022 REMEDIATION SYSTEMS OPERATION AND MAINTENANCE BOZEMAN LANDFILL July 14, 2021 CLIENT: CONSULTANT: The City of Bozeman Tetra Tech, Inc. P.O. Box 1230 851 Bridger Drive, Ste 6 Bozeman, Montana 59711-1230 Bozeman, MT 59718 Attention: Mr. Cody Flammond Attention: Mr. Kirk Miller INTRODUCTION The purpose of this task order is to conduct the oversight of operation and maintenance (O&M) of the landfill gas extraction system (LFGES) and remediation systems at the Bozeman Landfill for FY 2021-2022, and to conduct design of a system expansion to collect landfill gas (LFG) from the Lined Cell. The scope of work follows work activities from previous years with minor modifications and additional tasks. We have added three new tasks: 1) Task 500 Final design of three new LFG wells for the lined cell, 2) Task 600 Design and installation of piping from leachate UST to City sewer, and 3) Evaluate unlined cell cover thickness and permeability. This task order includes the following work activities: • Task 100 – LFG Extraction System Operation & Monitoring • Task 200 – SVE and AI System Operation & Monitoring • Task 300 – Leachate/Condensate Underground Storage Tank Monitoring • Task 400 – Database Entry and Management • Task 500 – Final Design of Three New LFG wells for Lined Cell • Task 600 – Design and Installation of Piping from Leachate UST to City Sewer • Task 700 – Evaluate Unlined Cell Cover Thickness and Permeability • Task 800 - Project Management and Reporting SCOPE OF WORK Tetra Tech’s proposed scope of work is summarized in the following tasks: Task 100 LFG Extraction System Operation & Monitoring Tetra Tech will conduct monthly monitoring and adjustment of individual LFG extraction wells, leachate pumps, and flare/compressor system. In addition, there will be regular service events for the flare/compressor system. These service events will consist of inspection of the compressor and compressor filter replacement, flare components inspection and testing, blower re-greasing, and related activities. DocuSign Envelope ID: 7A066529-2DAA-4C73-AA3E-B963C8C31805 Task Order – 2021-2022 Remediation Systems Oversight Bozeman Landfill, Bozeman, Montana July 14, 2021 Page 2 of 4 TETRA TECH Task 200 SVE and AI Systems Operation & Monitoring Tetra Tech will conduct monthly monitoring and adjustment of individual SVE and AI wells. The SVE and AI wellheads (within the bolt-down steel manhole covers) will be visually inspected every six months to ensure air-tight fittings and valves. A test of the effectiveness of the Air Injection system has been developed and will be implemented. Any recommendations for modification to the operation of the AI wells will be submitted to the City. Task 300 Leachate/Condensate Underground Storage Tank (UST) Monitoring Tetra Tech will conduct monitoring of liquid levels in the UST, calculate volume and accumulation rates, and conduct sampling of the liquid in the UST in accordance with City of Bozeman Water Reclamation Facility (WRF) requirements. Tetra Tech will also supervise the pumping and discharge of the leachate and condensate into City of Bozeman sanitary sewer. An inspection of the newly installed cathodic protection system will be conducted on an annual basis. Task 400 Database Entry and Management Information collected during monitoring and adjustment activities will be placed into a project database. This database will be maintained and updated following every monitoring event described in Tasks 100 and 200. The database will be used to evaluate operations and effectiveness of the systems. Task 500 Final Design of Three New LFG Wells for Lined Cell We initially proposed testing of methane concentrations in the Lined Cell to evaluate the need for connecting the Lined Cell to the existing LFGES. Upon further review of the size and history of the Lined Cell and the methane data collected above the cover in 2018, we modified this recommendation to move directly into a design phase of adding LFG wells to the lined cell. These LFG wells would ultimately be connected to the existing LFGES. Preliminary design of this system was conducted during FY 2021. Work tasks will include the following: • Refine location for three LFG wells within Lined Cell. • Develop final plans and specifications for three LFG wells, including surface connections and piping to the existing flare system and condensate traps and drain lines. These plans will extensively use designs from the original LFG system. • Assist the City with contracting and contractor selection. We anticipate the construction of this system will not occur until FY 2022/2023. TASK 600 Design and Installation of Piping from Leachate UST to City Sewer Leachate should continue to be pumped from the LFGES extraction wells. The rate of leachate pumping is reduced during the spring due to the leachate volume filling the UST almost daily, which poses logistical challenges related to emptying the UST. The pipeline would reduce operating costs for the LFGES and allow maximum leachate pumping rates from the LFGES wells. In 2020, the City decided to proceed with design of direct piping of the leachate UST to the City sewer located in the southwest corner of the landfill, however, due to staffing shortages they were not able to initiate the design in-house. Hence, Shawn Kohtz asked Tetra Tech to include this task in our Task Order. This task will included the following: • Design an 8-inch diameter pipeline to connect the UST that collects leachate and condensate from the LFG and SVE systems to an existing sewer manhole in the DocuSign Envelope ID: 7A066529-2DAA-4C73-AA3E-B963C8C31805 Task Order – 2021-2022 Remediation Systems Oversight Bozeman Landfill, Bozeman, Montana July 14, 2021 Page 3 of 4 TETRA TECH southwestern portion of the landfill property. This pipeline project is anticipated to include 1,100 ft of buried 8-inch pipeline and associated trenching and backfill, five manholes, mobilization, and related site controls (erosion control, site access, construction oversight, etc.). • Evaluate the stormwater flow into the manhole and determine if changes to that system are recommended or if a larger manhole needs to be installed to handle the total flow. • Assist City with contractor bidding, as necessary. • Provide oversight of the successful bidder on the City procurement, if requested under a separate approval. Task 700 Evaluate Unlined Cell Cover Thickness and Permeability The 2018 surface emissions sweep of the landfill cover did not identify escape of methane from the cover that would trigger New Source Performance Standards compliance issues. However, visual observations during trenching for the expanded LFGES indicates that portions of the cover are as thin as only one foot thick, which is less than the original 1995 design thickness of up to three feet. The dramatic increase of water flowing through the refuse in the landfill during the spring and early summer indicates that significant snowmelt is infiltrating the cover and entering the refuse. A brief evaluation of the effectiveness of the landfill cover should be conducted and recommendations developed. The end result may be repairs to the current cover and/or the design and construction of a thicker and lower permeability cover on some portions of the landfill. Conduct test pitting of unlined cell cover • Compile information from 2016 LFG expansion project relative to observed cover thickness and materials (photos, notes etc. identifying cover thickness) • Design and conduct test pitting program to map thickness and permeability characteristics of cover, including visual observation of cracks and settlement in cover. • Sample cover materials and conduct laboratory analysis of materials to estimate permeability • Compile report identifying where cover material appears to provide an inadequate barrier to infiltration of rainwater and snowmelt and/or off gassing of methane. • Develop recommendations as warranted for cover repairs or improvements Task 800 Project Management and Reporting Project management will include, scheduling of personnel, monitoring equipment/meters, and activities; communication with City of Bozeman and DEQ; data management; and invoicing. Reporting will consist of a brief summary of system operation and monitoring provided to City of Bozeman on a monthly basis, as well as technical memorandum for Tasks 500, 600 and 700. Tetra Tech’s Groundwater and Methane Monitoring Task Order for 2020-21 includes the development of a 3 to 5-year plan for larger system improvements and maintenance projects. Any needs identified by the work under this Task Order relative to the LFGES and SVE systems will be incorporated into future budget projections. PERIOD OF PERFORMANCE AND COSTS This task order will be applicable from July 1, 2021 through June 30, 2022. Estimated costs to complete the scope of work are shown below: DocuSign Envelope ID: 7A066529-2DAA-4C73-AA3E-B963C8C31805 Task Order – 2021-2022 Remediation Systems Oversight Bozeman Landfill, Bozeman, Montana July 14, 2021 Page 4 of 4 TETRA TECH TASK Estimated Costs Task 100 LFG Extraction System Operation & Monitoring $ 39,498 Task 200 SVE and AI Systems Operation & Monitoring $ 16,600 Task 300 Leachate/Condensate UST Monitoring $ 25,194 Task 400 Database Entry and Management $ 14,258 Task 500 Final Design of 3 New LFG Wells for Lined Cell $ 8,500 Task 600 Design and Installation of Piping from Leachate UST to City Sewer $ 21,200 Task 700 Evaluate Unlined Cell Cover Thickness and Permeability $ 13,000 Task 800 Project Management and Reporting $ 12,450 TOTAL $150,700 Our costs will be invoiced on a time and materials basis. A detailed cost estimate can be provided upon request. SPECIAL CONDITIONS: Execution of this Task Order constitutes acceptance of all terms and conditions contained in Tetra Tech’s Professional Services Agreement with the City of Bozeman, dated April 15, 2014. CLIENT: CONSULTANT: City of Bozeman Tetra Tech By: By: Printed Name: Printed Name: Kirk A Miller Its: Its: Senior Project Manager Date: Date: July 14, 2021 NOTICE OF CONFIDENTIALITY This Task Order (including attachments) contains information confidential to Tetra Tech, Inc., its subsidiaries, and subcontractors. It is intended only for City of Bozeman to consider Tetra Tech providing professional services at the Bozeman Landfill. Any other use is prohibited, without the prior written consent of Tetra Tech. DocuSign Envelope ID: 7A066529-2DAA-4C73-AA3E-B963C8C31805 7/28/2021 Jeff Mihelich City Manager