Poster 2

Going Mobile - Mobile Systems for Air Sparging Applications at NASA Sites Dean Pinson, P.E. – Geosyntec Consultants, Boca Raton, Florida Rebecca Daprato. Ph.D., Jim Langenbach, P.E. - Geosyntec Consultants, Cape Canaveral, Florida

Introduction

Design Details of Mobile AS Unit No.1 for SW3 Site

Going Mobile

Geosyntec was tasked to prepare two Resource Conservation and Recovery Act (RCRA) Corrective Measures Designs (CMDs) for the National Aeronautics and Space Administration (NASA). The CMDs include individual mobile air sparging (AS) systems for two sites associated with this project: Supply Warehouse No. 3 (SW3) and Former Development and Testing Laboratory (FDTL). The sites are located at Kennedy Space Center (KSC) in Florida.

Control Panel

Air sparging was chosen as the remedial option for both sites because both SW3 and FDTL have chlorinated volatile organic compound (CVOC) groundwater impacts and generally favorable sandy, permeable aquifers (typical to Florida). Geosyntec was contracted by NASA not only to design the AS systems, but to obtains bids and purchase the mobile AS equipment trailers. Focusing on flexibility and ease of use, the mobile AS equipment trailers were designed to meet the requirements for the initial sites referenced above, but also with operational flexibility and the ability to mobilize the units to additional locations in the future. The AS equipment trailers can be potentially utilized for (i) air sparge pilot testing, (ii) remediation of sites with limited, low-level VOC impacts, and (iii) treatment of VOCimpacted groundwater plumes and source areas.

Heat Exchanger/ After Cooler Air Compressor Image 2: Typical Mobile Trailer Interior Piping & Equipment Installation

Going Mobile

Advantages Associated With The Purchase of Pre-plumbed, Pre-wired Remedial Mobile Systems •

Minimizing time on-site required for installation and start-up − Major equipment components pre-tested by vendor (e.g. compressor, heat exchanger/after cooler, solenoid valves). − Bulk of equipment, wiring, and piping installations completed by vendor. − Equipment integration tested by vendor prior to site delivery (e.g. Programmable Logic Controller (PLC) controls, timers, alarms, automatic shutoffs, telemetry).

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Minimizing complexity of system connections required on-site − Only main power electrical connection typically required. − Minimal piping connections required to connect trailer equipment piping to field piping.

Image 1: Typical mobile remediation system trailer. Advantages of Mobile Equipment vs. Fixed Building Installations •Mobility − Can be transported by standard non-commercial size truck. − −

Readily transported for utilization at a different site. Easily removed from site after remedy completion (for aesthetic reasons or for site redevelopment purposes).

− Possible telemetry connection required (unless cellular based). •

− Vendors do this for a living and are good at it!

Easier process compared with fixed equipment building.

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Less approval & permitting required. Less time on-site required for installation.

Key Features of Mobile Air Sparge Unit No. 1: • 20 hp blower capable of 160 cfm against 23 psi.

•Cost-effectiveness − Trailer costs are very similar cost to a fixed equipment building.

• Three sparge legs for connection to separate air sparging zones.

Note: Mobile units designed for NASA KSC sites are likely less expensive due to building upgrade requirements to meet hurricane wind load standards. The designed mobile trailer units are only required to meet NASA KSC tie-down standards.

• Solenoid-controlled sparge legs for independent air sparging zone control.

•Flexibility − Short term air sparge pilot testing.

• Cellular based telemetry (NASA SW3 site lacked existing phone utility and connection infeasible)

− Limited duration treatment of low-level VOC-impacted areas. − Long term remedy for high-level VOC-impacted areas. Note: Air sparge remediation systems are typically designed to operate for a shorter duration than the useful life of the equipment; therefore, once the remedy has been completed, a mobile air sparge configuration facilitates transport of the equipment to other sites for various uses.

Note: Mobile Air Sparge Unit No. 2 for FDTL site has a similar design as Mobile Air Sparge Unit No. 1, except for a larger 25 hp compressor and a total of six air sparge legs.

Figure 1: Typical trailer layout.

Additional Details of Mobile Air Sparge Unit No. 1: • System equipment designed for possible future capacity requirements: −Additional 3rd sparge leg (remedy of SW3 site only required control of two AS zones).

Design Details of Mobile AS Unit No. 1 for SW3 Site

•Equipment placement −

Figure 2: Piping & Instrumentation Diagram for Mobile Air Sparge Unit No. 1 for NASA SW3 site.

Equipment constructed/assembled by vendors that specialize in layout/ assembly of remediation equipment

−PLC with additional inputs/outputs for future use. • Extra interior working height to 6.5-ft facilitates mobility of personnel during O&M activities. • Minimization of interior piping and wiring runs within trailer due to limited space. • Explosion-proof rated wiring was not required since air sparge equipment process involves supplying compressed air. Note that other remediation processes, including SVE and GW Pump & Treat require explosion-proof wiring since contaminated media would flow through system equipment.

Economic Details • Individual bids for the two mobile units designed for the NASA sites ranged from $50,000 to $60,000 (including taxes, shipping, and start-up assistance). The primary reasons for the cost difference between the two mobile AS units were the compressor sizes (20 hp vs. 25 hp) and number of air sparge legs (Mobile Air Sparge Unit No. 2 has six air sparge legs). Therefore, smaller and less complex mobile units have the potential to cost significantly less. • Overall project costs can be significantly less by having a vendor perform the bulk of the interior installations and testing prior to delivery compared with the purchase of individual components and on-site assembly.