Okaloosa County BOCC — January 6, 2015 — SCSTO45 NLF--VZAInjectionExtract--FullyExecuted — reading text

from SCS' installation and pretesting report. Task 1 Estimated Fee: $3,400 Mr. Scott Henson May 7, 2012 Page 4 Task 2: Soil-Gas Probe Installation and Vent Well Repair SCS proposes to install an additional cluster of three soil-gas probes to be placed between the two current injection/extraction wells, A-1 and A-2. The additional soil-gas probes will be installed and completed in the same manner as the currently existing probes, and will consist of installing 1" polyvinyl chloride (PVC) pipe with 0.0 l-inch machine slotted screen at approximately 25, 35 and 50 feet below ground surface. The additional soil-gas probes will be for collection of data on air and vapor pressure and quality to be collected at the point of injection. The lack of pressure and gas data at the point of injection was a noted issue of concern with respect to the Phase I VZA pre-testing, and was a key factor in preventing a precise radius of influence (ROI) from being calculated. SCS conducted a site visit to the Niceville Landfill (NLF) on January 5, 2012 and discovered fuat one of the vent wells (V-2) had been broken offbelow grade. Upon further examination, it was discovered that most of the vent wells had been disturbed and appeared to be loose at the base of each vent riser pipe. This task includes repairing the vent wells and adding a concrete pad around each vent to help prevent future disturbance of the vents. Task 2 Estimated Fee: $8,800 Task 3: Injection and Extraction Operation/ Data Calculation It appears that preferential airflow pathways were created during the Phase I VZA pre-testing, and air flow was able to reach monitoring points at the 150-foot mdius from the point of injection. However, system operation in extraction mode was not conducted as part of Phase I of the pilot study test. SCS, in conjunction with UF, proposes to conduct a series of short tests during the first 12 weeks of system start-up to compare and assess the effects of extraction versus injection at three varying flow rates (i.e., 10, 30 & 50 scfm). Each flow rate will be conducted at both injection and extraction continuously for two-weeks, while weekly soil-gas measurements are collected. Data obtained from the varying flow rates will be compared to assess which operational method provides the greatest increase fn subsurface oxygen, and thus will be utilized for the remainder of the Phase I VZA testing. During the injection phase of the testing, the vent wells will be plugged to prevent air flow escape. Vent well plugging may also be implemented during the extraction phase in an effort to increase the radius of influence (e.g., plug only the interior vent wells and ·allow the exterior wells to remain o·pen in an effort to increase airflow at the for extents ofth~ radii). Itljection and extraction operations are anticipated to begin in April 2012 and continue through December 2012. This task also includes project time for Dr. Tim Townsend ofUF, who may be needed to assist in implementation, coordination, or review of the injection and extraction operations. Task 3 Estimated Fee: $105,500 Mr. Scott Henson Moy7,2012 Page 5 Task 4: Groundwater Sampling As Task 3 injection and extraction operation work is being performed, monthly groundwater samples will be collected during a ten-month system operational sampling period (assuming operational period of July- April2012). The existing wells which will be sampled include two groundwater wells installed for this test (VZA-1 & VZA-2) as well as two existing groundwater monitoring wells (down-gradient well, MW-6R; and up-gradient well, MW-8) in the existing landfill monitoring well network. Parameters which are to be measured include: conductivity, dissolved oxygen, oxidation reduction potential (ORP), pH, water levels, ferrous iron, total iron, total arsenic, total manganese, and total organic carbon. VOC samples will be collected three times during the course of the project consisting of once at the initial system start-up and operation, once at the midway point of operation, and again at the conclusion of the injection and extraction operation. Samples also will be collected for quality assurance/quality control (QA/QC) purposes. These will include the following for each groundwater sampling event: one duplicate sample for all parameters, one trip blank for volatile organics on the events that are sampled for VOCs only, one equipment blank for all parameters, and associated Level II laboratory QC analyses. Task 4 Estimated Fee: g7,000 Task 5: Dafg Assimilation and Reporting Upon completion of the 10- month injection and extraction operation and the groundwater monitoring, SCS will prepare a detailed report outlining the results of the soil-gas data, groundwater analytical results, and the operational outcome of the injection and extraction phase. The report will include an analysis of pre-test groundwater data versus groundwater data collected over the course of the injection and extraction process as it relates to specific changes in the geochemistry. SCS has also included costs to develop a 3-D visualization model depicting the groundwater data that will include soil-gas measurements, using Leapfrog software. The model will be used to depict real time information concerning vadose zone and groundwater response to the injection/extraction operation. Task 5 Estimated Fee: 1}7.300 TOTAL ESTIMATED FEE The total estimated fee for the above tasks is $182,000. Mr. Scott Henson May7,2012 Poge 6 SCHEDULE SCS has prepared a preliminary schedule for perfonnance of the VZA pilot study (Attachment B). This preliminary schedule will be updated from time to time as the project is executed. Asswning the pilot study is initiated by May 2012 and no delays occur beyond SCS' control, the balance ofFY2012/13 will include performing Tasks 1-5. TERMS AND CONDITIONS These services will be completed according the current tenns and conditions of our existing agreement (Contract # C06-1353-PW) with Okaloosa County. These services will be invoiced monthly on a time and materials basis. Mr. Scott Henson May 7, 2012 AUTHORIZATION If the Scope of Services, schedule, and associated budget are acceptable, please provide your authorization to proceed by signing and returning the attached task order authorization. SCS appreciates the opportunity to provide environmental consulting services to Okaloosa County. Should you have any questions or require additional information, please contact Bob Westly or Nicolas Howard at 850-432-6211. Sincerely, Robert L. Westly, P.G., CPO K. Mark Tumlin, MBA Project Director Vice President SCS ENGINEERS SCS ENGINEERS RLW/KMT:rw Attachments cc: Nicolas Howard, SCS John Cooey, SCS Ray Dever, SCS  Attachment A Manpower and Fee Estimate  ATT40IMJliiT 4- M.UIPOWEIIAND n!E llS'llMATB- PIWPOS.U.I-116211- !14.,-lOll OK.U.OOSA COUNTY- NICEVILLE LANDFILL VZAINIJ!CnOH A&XTIIACllDN. PY liDll - Ollico!);_A&.._ ~Dirocro<CBol> Weoolvl Sooior Pn:,iecl M..._ i""ioct ~(PfocHD-d) I ' I 1 6 ) ol() 115 • 5 14 130 Tulos~) 6 7 I ' \0 II u Tolol lc""""l 0 10 0 2611 .... (SJ \IS ... 195 \ZS