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1 51 <br />. extraction wellheads to the treatment compound Care was taken not to damage the sanitary <br /> seals of the vapor extractions wells when the conveyance piping was connected A 2-inch PVC <br /> "T" was used as the connector between the piping and the wellhead After locking caps were <br /> installed, a traffic-rated street box was re-installed over each wellhead The street boxes <br /> measured approximately 14 inches in diameter and were placed in a level position approximately <br /> '/z inch above ground surface Each box was set in concrete with a 1/4 inch slope away from the <br /> access lid Cross-sections of the trench and underground piping are shown on Figure 3 <br /> Prior to backfilling, all of the piping was pneumatically pressure tested Each pipe held a <br /> minimum of 20 psi for 15 minutes without a detectable loss of pressure The trench was <br /> backfilled using sand and selected native material The surface of each trench was restored to <br /> match the existing conditions <br /> 23 Aboveground Piping Installation <br /> The soil vapor extraction piping is routed aboveground when it reaches the treatment compound <br /> to form a manifold Gate valves were installed before the manifold to allow independent <br /> regulation of the air flow from individual wells Sampling ports were installed dust before the <br /> mamflod to allow independent sampling of the vapor streams from each of the vapor extraction <br /> wells Threaded access plugs were installed on each soil vapor line to allow the use of <br /> instrumentation for the independent measurement of the flow rate from each of the extraction <br /> wells All aboveground piping within the treatment compound consists of Schedule SO PVC with <br /> the exception of the piping run from the blower to the thermal oxidizer which is steel <br /> 24 Treatment Compound Construction <br /> A 4-inch thick concrete slab was installed at the southeast corner of the site to provide a level <br /> floor for the remediation compound The compound was then enclosed by a 6-foot high chain- <br /> link fence with a 12-foot wide locking gate The fence and gate have plastic privacy slats which <br /> help conceal the remediation equipment <br /> 440pgg RPT SECOR <br /> 0 Job No NOOOI-006-01 3 Sgh=ber 12,19% <br />