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4 WORK PLAN UNDERGROUND STORAGE TANK REMOVAL Description of Excavation The sewer and utility lines that may transverse the excavation will be supported utilizing"H"beams and/or 4"x 4"lumber, straps and chains. This will enable the utilities to remain functional throughout the duration of the project. Soil samples will be collected In the locations specified by County regulators and submitted to a state- certified laboratory for analyses appropriate for the Number 6 fuel oil contents of the UST. In the event that the analytical results of soil samples indicate a fugitive release from the tanks, the impacted area will be further excavated under the direction of the HLA Project Manager. Measures will be taken to delineate the potentially impacted soil from the clean backfill. This will be accomplished through visual and olfactory observations. In the event that the storage system remained secure during usage, the excavation will be properly backfilled with clean backfill materials and compacted to the contract specifications. REMOVAL PROCEDURES Removal of Fuel and Sludge Residual fuel and sludge will be transferred to vacuum trucks and transported under manifest to a disposal facility(see accompanying list). Cleaning of Concrete UST Bottom and Sidewalls and Piping The concrete bottom and sidewalls of the UST will be steam cleaned utilizing a 3,000 PSI steam cleaner, rotating jet nozzles,and Hotsy Ripper H detergent The associated piping of the tanks will be excavated and steam cleaned at the same time as the concrete UST with the resulting rinseate flushed into an onsite Baker tank or equivalent The resulting rinseate and sludge will be removed by a vacuum truck and transported under manifest to an approved disposal facility(see accompanying list). The Project Manager will contact the County regulatory agent and any other organization 48 hours in advance to schedule the efficient oversight of UST removal operations. Once the UST has been inspected and found to be clean. The concrete bottom and sidewalls of the UST will be broken up,removed from the excavation and crushed into manageable pieces for disposal at a concrete recycler. The concrete will be loaded into end dumps and transported to an approved concrete recycler or to a landfill as inert construction debris. Alternatively, with the approval of the HLA Project Manager the concrete will be crushed into 4-inch minus pieces, any rebar in the material removed and the crushed concrete will be used as backfill. DUST CONTROL In the event that particulate matter emissions become significant, dust control measures will be achieved utilizing a 500 gallon capacity water wagon with a spray bar and 1-1/2"hose with an adjustable nozzle. The area to be excavated will be moistened prior to and during the excavation. Special care will be taken to ensure that unnecessary amounts of water are not used so as to prevent muddy or ponding site conditions. G.,\WP\GDH\GH41017E.354 Harding Lawson Associates 2