BANNOCK COUNTY PUBLIC WORKS 5500 S. 5 TH AVE POCATELLO, ID 83204

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1 BANNOCK COUNTY PUBLIC WORKS 5500 S. 5 TH AVE POCATELLO, ID The following is a Request for Proposal (RFP) for the Fort Hall Mine Landfill (aka Bannock County Landfill) in Pocatello Idaho. The objective of the RFP is to select a firm to provide professional services relating to the groundwater remediation activities currently being conducted at the site and groundwater sampling. A mandatory pre bid meeting will be held in the conference room at the Landfill on June 29, 2016 at 1:00 P.M. MDT. The address for the Landfill is 1500 N. Fort Hall Mine Road, Pocatello, ID Those unable to attend the meeting in person can attend the meeting via conference call at This RFP includes summaries of the following: 1. Background information 2. Treatment System Background and Performance 3. Scope of work 4. RFP submittal deadline 5. Selection Background Information In October 1991, groundwater samples from wells near the Landfill were found to be contaminated with trichloroethylene (TCE), tetrachloroethylene (PCE), and other volatile organic compounds (VOCs) originating from Cell 1. By 1992, high concentrations of TCE were in observed downgradient wells in the Portneuf Valley, and several municipal wells were closed. In May 1993, Bannock County entered into a Consent Order with the Idaho Department of Health and Welfare pursuant to Idaho Code (Idaho Environmental Protection and Health Act) to assess and mitigate the impacts of Cell 1 on groundwater. In 1993, the County

2 completed closure of Cell 1 by capping Cell 1 with 3 feet of soil and directing surface runoff away from the buried waste. By September 2000, contaminant concentrations in downgradient municipal wells had decreased to less than the maximum contaminant level (MCL). In August 2002, the County installed a groundwater pump and treat remediation system. The pump and treat remediation system consisted of groundwater pumping wells and an air stripper to treat the pumped water. Beginning in October 2009, groundwater samples associated with Cell 2 began to exhibit PCE contamination at levels well below the MCL. By October 2012, a total of 10 parameters and constituents were found to be present at Cell 2 in concentrations above background. In March 2015, the Idaho Department of Environmental Quality (DEQ) completed a review of the groundwater program at Cell 1. DEQ concluded that the remediation system, constructed and operated pursuant to the 1993 Consent Order, has largely been ineffective at removing contamination from the environment. In June of 2015, the County submitted a report to the DEQ which included an investigation of the possible sources/causes of chlorinated solvents in Subtitle D wells located around the active Cell 2. The report was rejected for scientific and technical flaws. The DEQ s review further found that TCE concentrations at the only monitoring well off landfill property, MW 103S, exceed the MCL. The DEQ concluded that the nature and extent of the TCE plume is insufficiently characterized and the conceptual model, upon which the remediation system was designed, does not appear to accurately represent the site. In August 2014 and September 2015, the DEQ directed the County to fulfill the requirement of 40 CFR , Assessment Monitoring, to address the observed contamination at Cell 2. The County disagrees with the DEQ that Cell 2 is a source of contamination. In early 2016, the DEQ submitted a new Fort Hall Mine Landfill Consent Order to Bannock County which, to date, the County has not agreed to or signed. Cascade Earth Sciences collected and analyzed groundwater samples in January The January 2016 groundwater monitoring event included measuring water levels and collecting samples from monitoring wells MW 01, MW 101S, MW 102S, MW 103S, MW 104D, W 104S, MW 105D, MW 105S, MW 111S, MW 111D, MW 112D, MW 112M, MW 112S, MW 113D, MW 113S, MW 116S, MW 117D, MW 117S, MW 118D, MW 119S, MW 120D, MW 120S, MW 121 and recovery wells RW 1, RW 2, RW 3, RW 4, RW 5, RW 9R, RW 10, RW 15, and RW 17. Groundwater samples were analyzed for Appendix I.

3 At the request of the DEQ, all groundwater monitoring wells are analyzed for Appendix II constituents on an annual basis. For more information on groundwater quality please see the provided report Groundwater Remediation System Combined Report for Fourth Quarter 2015 (October) and First Quarter 2016 (January) Bannock County For Hall Mine Landfill, Cascade Earth Sciences, May Treatment System Background and Performance The Site currently operates nine groundwater pump and treat wells. The water is treated by an on site air stripper then injected back into the aquifer via an on site injection well. A total of 7,626,798.8 gallons of water was pumped and treated in The system has removed a total of 1.6 gallons (20 lbs.) or TCE in since start up. Well locations are based on the report Final Phase 3 Remedial Investigation Report, completed by Maxim Technologies, Inc. in May The report made various assumptions about groundwater movement as well as the permeability of the geologic layers. The assumptions have subsequently been invalidated. Groundwater is primarily located within the alluvial sediments and the upper portion of the Starlight Formation. Each recovery well is screened above, and partially into, the lower Starlight Formation. The recovery wells are located downgradient of the closed Cell 1. The injection well is located downgradient of the air stripper on the bank of the first storm water retention pond. If the injection well overflows, due to clogging or inflow exceeding the capacity of the well, it does so into the pond. The air stripper and remediation shed sump pump are fitted with alarms to control the system overflow. The County completed an assessment of the remediation system in The assessment identified gaps in the groundwater recovery system. As a result additional recovery wells were installed in , RW 9R and RW 10. RW 9R replaced RW 9 and RW 10 filled in a gap between RW 4 and RW 5. Another assessment to evaluate the effectiveness of the remediation system was completed in The assessment identified additional gaps in the recovery wells and recommended the installation of additional wells. A total of three new wells were installed in the fall of RW 15 and RW 16 filled in gaps between RW 1 and RW 4. RW 17 was installed up gradient of RW 15 and RW 16. RW 16 has not produced an adequate amount of water to function as a pumping well.

4 All of the recovery wells are equipped with variable frequency drive pumps that are controlled by water level transducers. The initial phase of a landfill gas collection and control system (GCCS) was installed in The initial phase consisted of 32 landfill gas (LFG) wells. 19 LFG wells were installed in Cell 1 and 13 wells were installed in Cell 2. The GCCS was expanded in 2014 with the addition of 9 LFG wells in Cell 2. The GCCS currently consists of 39 functioning LFG wells with 17 located in Cell 1and 22 located in Cell 2. The County expects to complete another expansion of the GCCS in the fall of The GCCS is connected to an electricity generation facility with a utility flare backup. The electricity generated is sold to Idaho Power. Scope of Work The County is currently working with the DEQ to define the required tasks and responsibilities to remediate the contamination, to the extent possible. However the County anticipates that the scope of work will include, at a minimum: 1. Review historical groundwater monitoring data; 2. Complete/update groundwater statistical analysis; 3. Develop an offsite groundwater monitoring plan in order to define the extents of the existing contaminant plume; 4. Update the Conceptual Site Model and Site Characterization Plan. 5. Revise/update the existing groundwater remediation plan; 6. Evaluate the effectiveness of the existing treatment system and recommend alternative treatment methods, if applicable; 7. Review landfill activities and operations to minimize potential sources of contamination; 8. Collect groundwater samples and submit for analysis; 9. Interact with the DEQ. RFP Submittal and Deadline Proposals should include the following: Summary of firm background including projects involving groundwater contamination remediation and specifically where dense non aqueous phase liquids were involved Scope of work including the methods to address the items requested Short resumes of the staff members expected to be involved in the project (½ 1 page max each) Summary of experience working with the DEQ

5 Hourly rate sheet, see below Anticipated project schedule Please submit your RFP response/bid by 5:30 P.M. MDT, July 11, 2016 via to Responses/bids received after the deadline will be discarded without review. Rate sheets should be sent in a clearly labeled and sealed envelope via USPS, FedEx, UPS, or similar, and should be received by 5:30 P.M. MDT, July 15, Rate sheets should be sent to: Jeremy Welch 5500 S. 5 th Ave Pocatello, ID Please contact Jeremy Welch (jeremyw@bannockcounty.us) before 5:30 P.M. MDT, June 30, 2016 with any questions regarding this RFP. Responses to questions will be ed to proposers on July 5, Questions submitted in person or via phone will be ignored. Selection The County will review the proposals and select a consultant based on the information and qualifications provided in the proposal. Pursuant to Idaho Code (2)(i), rate sheets will not be used for the purpose of ranking applicants. If needed, Bannock County will perform interviews of selected firms the week of July 18, The County anticipates that a consultant will be selected by July 21, 2016.