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HomeMy WebLinkAboutTetra Tech Task order for Soil Gas Investigation at Landfill TASK ORDER/ PROPOSAL SOIL GAS INVESTIGATION BOZEMAN SANITARY LANDFILL February 13, 2013 CLIENT: CONSULTANT: The City of Bozeman Tetra Tech, Inc. P.O. Box 1230 851 Bridger Drive, Ste 6 Bozeman, Montana 59711-1230 Helena, MT 59715 Attention: Mr. Dustin Johnson Attention: Mr. Mark F. Pearson This task order/proposal, for a soil gas investigation is presented to the City of Bozeman in response to a request by Bozeman Landfill representatives during a meeting with Tetra Tech personnel on January 16, 2013. The purpose of this investigation is the following: ■ Assess the presence of volatile organic compounds (VOCs) in soil gas in the area of groundwater impacted with VOCs beneath a residential neighborhood south of and adjacent to the Bozeman Landfill ■ Provide a preliminary evaluation of the lateral and vertical distribution of VOC concentrations in soil gas, if VOCs are detected ■ Use the information gained in this investigation to assess the potential for gas (vapor) intrusion to occur in residential structures in the subject neighborhood The investigation is proposed to occur in public right-of-way (ROW) along streets: Saint Andrews Drive, Tumberry Court, and Caddie Court (Figure 1). A minimum of 16 soil gas probes in eight locations is proposed. SCOPE OF SERVICES: The following scope of services includes preparation for and implementation of an investigation of soil gas in a residential neighborhood immediately south of the landfill property. Soil gas probes will be installed, at two depth intervals in each of the eight proposed locations (Figure 1), using Geoprobe direct push drilling techniques. Samples of soil gas will be collected and submitted for analysis of VOCs. Results will be evaluated and a report prepared for City of Bozeman. The scope of services is described in detail below: Task 1 Development and Preparation of Task Order Approach A review of standard practice investigative methodologies has been conducted to support preparation of this task order. References include guidance publications from U.S.E.P.A., California, and Montana. A minimum of two capable Geoprobe® companies will be solicited and their bids compared for a best price. Tetra Tech Task Order/Proposal Page 2 of 5 Soil Gas Investigation, Bozeman Sanitary Landfill February 13, 2013 Task 2 Preparation for Investigation Preparation for the investigation will involve procurement of sampling equipment, utility clearance, and preparation of a site health & safety plan. Also included in Task 2 is the option to prepare a neighborhood communication document. Procurement of gas sampling equipment The procurement of gas sampling equipment will include probe tips, tubing, valves, and steel probe protectors. The probe tips, tubing, and valves will consist of materials that do not sorb VOCs. Underground utility clearance Drilling locations will be marked at the site. The Utilities Underground Location Center (UULC) will be contacted to clear all drilling locations of underground utilities. Tetra Tech personnel will mark the field locations and then field check the clearances and communicate with UULC personnel to confirm utility clearance at each drilling location. The eight soil gas probe locations are shown in Figure 1. Preparation of Job Safety Analysis A Job Safety Analysis (JSA) will be prepared that will review the sequence of basic job steps, potential hazards, and recommended action of procedure to address potential hazards. The JSA will be communicated, reiterated, and revised (as necessary) in meetings with all field personnel at the start of each work day. Preparation of neighborhood communication plan A neighborhood communication plan would be prepared for distribution at each residence along the above mentioned streets. It is proposed that the plan be a folded 'leaflet' that will be attached to the front door of each residence in the neighborhood. This one to two page document would state that monitoring activities have been and are continuing to be conducted in the neighborhood. These activities have included the sampling of groundwater and currently, soil gas to evaluate environmental impacts from the adjacent landfill. The document would provide a brief summary of the activities that will be occurring, and provide contact information at the City of Bozeman in case of questions. Task 3 Field Investigation Plan and vertical distribution of soil gas samples As mentioned above, the approach to this soil gas investigation is to have up to eight locations where soil gas can be sampled at two specific subsurface elevations described as a 'deep' probe and a 'shallow' probe. Soil gas results from these intervals will be used to assess the occurrence of VOCs in soil gas in the neighborhood. Tetra Tech Task Order/Proposal Page 3 of 5 Soil Gas Investigation, Bozeman Sanitary Landfill February 13, 2013 Sampling from two depths at each location is recommended as it will provide information on the site-specific vertical attenuation of VOC concentrations, if detected. Therefore, the field investigation would consist of installing probes at 20 and 10 feet below ground surface (bgs) at each location. However, in the event of groundwater being intercepted at, or less than, 20 feet bgs, the deep probe would be installed approximately two feet above groundwater and the shallow probe would be installed approximately five to eight feet above the deep probe but no shallower than five feet bgs. If groundwater is encountered at depths of less than approximately 10 feet bgs at any location, then only one probe would be installed at that location, approximately 2 feet above groundwater. Geoprobe®activities At each location, the Geoprobe® will push down to a maximum of 20 feet depth, unless groundwater is encountered at a shallower depth. The holes will be "cored" which means that a hollow steel tube (of approximately 2 1/4 inch diameter) will be pushed down and a soil sample collected (within the steel tube). The steel tube sections will be in four foot lengths and allow an assessment of geologic materials and the detection of groundwater. Probes will be installed in a manner similar to installation of a monitoring well in that there will be filter screen material around the probe, topped by bentonite and hydrated bentonite, upward, to the shallow probe interval. The shallow probe completion will be the same as the deep probe completion, followed again, by bentonite and hydrated bentonite to within one half foot of the surface. The filter screened intervals around the probe will be approximately 1 foot (i.e., 6 inches above and below the probe). Each completed soil gas probe will consist of relatively inert materials such that VOCs will not be sorbed or produced by these materials. Each probe will consist of a stainless steel implant (gas permeable tip) connected to a length of Nylaflow tubing. The tubing will be terminated at the surface with a one-way polycarbonate stop valve. The tubing and valves at the surface will be protected by a flush-mount, bolt-down, steel manhole of approximately 5 inches diameter. The manhole will be secured with concrete grout. It is anticipated that the soil gas probes, at each of the eight locations in the neighborhood, will be in the boulevard portions of the public ROW, or between the sidewalk and the street curb. If the investigation is conducted in the winter months, it may be expected that up to two feet of snow will exist in the boulevards, due to the routine snow clearing of the street and sidewalks. It will then be necessary to clear the drilling locations of snow prior to the field investigation. Tetra Tech supervisory and monitoring activities Tetra Tech personnel will supervise the installation and initial purging of the soil gas probes and insure that all of the probes sites are left clean and without impact to the boulevard. Purging of a minimum of three bore volumes (filter pack plus tubing) will be conducted immediately after probe installation. This will be followed by an equilibration period of at least 24 hours, before collection of soil gas samples can be conducted. Tetra Tech Task Order/Proposal Page 4 of 5 Soil Gas Investigation, Bozeman Sanitary Landfill February 13, 2013 Sample collection and shipment to laboratory A minimum of 24 hours will pass, to allow for equilibrium conditions, before the probes are re- purged and sampled. At the time of sampling, three tubing volumes will be removed before filling SUMMA canisters (one per soil gas probe) at a maximum flow rate of 200 milliliters per minute. The sampling of the probes will be accomplished in one monitoring event that could be up to two days duration. Tetra Tech personnel will sample the probes and submit the samples to an accredited analytical laboratory for analysis. One duplicate sample will be collected. Laboratory analysis Laboratory analysis will consist of each sample being analyzed for VOCs in accordance with TO-15 SIM method. The component list will match what has been detected in groundwater, include components with a low EPA screening level that were detected in the first phase of analysis of soil gas in methane monitoring probes at the Bozeman Landfill (October 2012), and any daughter products. Analytical detection limits for the analytical components including chloroform, tetrachloroethene, trichloroethene, and vinyl chloride will attempt to match the U.S.E.P.A. Regional Screening Levels (RSLs). Task 4 Project Management, Data Analysis, and Report Preparation Task 4 includes the activities of project management, data analysis, and report preparation. Project management The project will be managed by Mark Pearson located in the Tetra Tech Bozeman, Montana office. Senior oversight of the project will be conducted by James Elliot in Tetra Tech's Santa Barbara, California office. Project management will include contracting of a Geoprobe® company, field activities scheduling, and communication with City of Bozeman regarding drilling progress/issues, communication with the analytical laboratory, possible communication with the public or neighborhood regarding the investigation, and review and submittal of invoicing. Data analysis and Report Preparation Data analysis will be conducted by the above Tetra Tech personnel. The objective of the data analysis will be to evaluate the occurrence of VOCs in soil gas and assess the potential for gas intrusion. If VOCs are detected, then Tetra Tech will use a predictive modeling program: Johnson & Ettinger as another method of assessing the potential for gas (vapor) intrusion. A report will be prepared summarizing the findings of this investigation. This will include the above data analysis and evaluations. Conclusions and recommendations will also be included, as appropriate. If VOCs are detected in soil gas, then a recommendation will be made to conduct a second sampling event during the highest groundwater elevations. This would typically be in June. Tetra Tech Task Order/Proposal Page 5 of 5 Soil Gas Investigation, Bozeman Sanitary Landfill February 13, 2013 PERIOD OF PERFORMANCE: Activities covered in this task order will begin upon approval of this task order. The subtasks and anticipated completion times are as follows: Task or Subtask Anticipated Time of Completion • Task i Development and Preparation of Task Order Approach Completed • Task 2 Preparation for Investigation Within two weeks • Task 3 Field Investigation Within one month • Task 4 Project Management, Data Analysis,and Report Preparation One month after field Investigation COMPENSATION: Estimated cost to complete the foregoing scope of services for 16 soil gas probes at eight locations is $25,933. AttachmentA details these costs. All services in this task order will be conducted on a time and materials basis. 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 January 3, 1994 and Amendment Nos. 1, 2, 3, and 4 of the Professional Services Agreement dated July 31, 1995; January 1, 1996; March 17, 1997; and December 10, 2001, respectively. CLIENT: CONSULTANT: City of Bozeman Tetra Tech By: By: Its: Its: 9 ✓ Michael Hatten, Senior Engineer Date: Date: Z /3 NOTICE OF CONFIDENTIALITY This Task Otoei(including attachments;contains information confidential to Tetra Tech tnc its suosrdiaries. and subcontractors 11 is intended only to Cit),of Bozeman to considei Tetra Tech providing protessionai services a! the Bozeman Landfill profec?site Any otnet use is prohibiteo. w•itnout roe prior written consent of Tetra Tech Tetra Tech fi I a -0 c0 — _ -- - d N N 7 -- - -- - , O O - - •- CDm a com m c o to E ;. .. 2 m o 0 O O O N G i 0 o w o « � m CD _0 c 3 ` c E c d O O O L O 47 � t i- y N 1 m ;�. a Q . 00 T' . C� o a>r- ��•-� r ¢ r � s F� 1 » m O CD • m co o AaC �3 U- J V J OI — 7 a .c O J m ATTACHMENT A ATTACHMENT A COST ESTIMATE SOIL GAS INVESTIGATION BOZEMAN SANITARY LANDFILL BOZEMAN,MONTANA February 13,2013 Units Unit Cost Amount Task 1 Development and Preparation of Task Order Approach Investigative methodology review and Preparation Sr.Project Manager,per hour 2 $157.00 $314.00 Tetra Tech Project Manager/Hydrogeologist,per hour 2 $88.00 $176.00 Driller solicitation Tetra Tech Project Manager/Hydrogeologist,per hour 2 $88.00 $176.00 Task Order Preparation Sr.Project Manager,per hour 1 $157.00 $157.00 Tetra Tech Project Manager/Hydrogeologist,per hour 20 $88.00 $1,760.00 TASK 1 TOTAL $2,583.00 Task 2 Preparation for Investigation Procurement of gas sampling equipment Tetra Tech Project Manager/Hydrogeologist,per hour 4 $88.00 $352.00 Materials for gas sampling,estimate 1 $200.00 $200.00 Underground Utility and Right-of-Way clearance Tetra Tech Project Manager/Hydrogeologist,per hour 4 $88.00 $352.00 Preparation of Job Safety Analysis Tetra Tech Project Manager/Hydrogeologist,per hour 1 $88.00 $88.00 Preparation of neighborhood communication plan and distribution Sr.Project Manager,per hour 1 $157.00 $157.00 Tetra Tech Project Manager/Hydrogeologist,per hour 4 $88.00 $352.00 Clerical or Administrative Assistant,per hour 1 $65.00 $65.00 Materials,estimate 1 $50.00 $50.00 TASK 2 TOTAL $1,616.00 Task 3 Field Investigation (Assuming 8 locations with two soil gas probes at each location) Site(snow)Clearing Activities Rocky Mtn Dirt Detail Quote 1 $270.00 $270.00 Geoprobe Activities (Use Enviro Probe Cost Estimate-10 locations and 20 probe installations) Project Management,Mobilization,Travel,and Per Diem 1 $745.50 $745.50 Geoprobe Operation and Materials,per location with shallow and deep 8 $489.00 $3,912.00 probes Tetra Tech markup of 10%(of subcontractor time and materials) $49P.75 20%Contingency for Variables in Geoprobe Investigation $931.50 SUBTOTAL $6,351.75 Tetra Tech Revision Date:2/12/2013 Page 1 of 2 ATTACHMENT A COST ESTIMATE SOIL GAS INVESTIGATION BOZEMAN SANITARY LANDFILL BOZEMAN,MONTANA February 13,2013 Tetra Tech supervisory and monitoring activities (Assuming drilling and installation of 8 locations of 2 probes per location for a total of 16 samples) Sr.Project Manager,per hour 2 $157.00 $314.00 Tetra Tech Project Manager/Hydrogeologist,per hour 47 $88.00 $4,136.00 Clerical or Administrative Assistant,per hour 2 $65.00 $130.00 SUBTOTAL $4,580.00 Sample collection and shipment to laboratory 16 liter SUMMA Canister rental,each 17 $55.00 $935.00 (Includes one duplicate sample) Flow Control Valve Rental 4 $15.00 $60.00 SUMMA Canister Shipping to Bozeman,estimate 1 $400.00 $400.00 Shipping to laboratory,estimate 1 $400.00 $400.00 Tetra Tech markup of 10%(of subcontractor time and materials) $179.50 SUBTOTAL $1,974.50 Laboratory analysis TO-15 analysis,each 17 $140.00 $2,380.00 (Includes one duplicate sample) Tetra Tech markup of 10%(of subcontractor time and materials) $238.00 SUBTOTAL $2,618.00 TASK 3 TOTAL $15,524.25 Task 4 Project Management,Data Analysis,and Report Preparation Proiect management Sr.Project Manager,per hour 1 $157.00 $157.00 Tetra Tech Project Manager/Hydrogeologist,per hour 3 $88.00 $264.00 Clerical or Administrative Assistant,per hour 1 $65.00 $65.00 SUBTOTAL $486.00 Data analysis and Report Preparation (Includes time to input and run Johnson&Ettinger Model) Sr.Project Manager,per hour 7 $157.00 $1,099.00 Tetra Tech Project Manager/Hydrogeologist,per hour 45 $88.00 $3,960.00 CAD Specialist,per hour 8 $75.00 $600.00 Clerical or Administrative Assistant,per hour 1 $65.00 $65.00 SUBTOTAL $5,724.00 TASK 4 TOTAL $6,210.00 TOTAL OF ALL TASKS $25,933.25 Tetra Tech Revision Date:2/12/2013 Page 2 of 2