Technical Memorandum. To: [ REMOVED ] [ REMOVED ], URS

Transcription

1 Technical Memorandum To: [ REMOVED ] From: [ REMOVED ], URS Date: [ ], 2013 Subject: Anaytical Results for Stormwater Treatment System Sampling at [ REMOVED ] INTRODUCTION This techincal memorandum presents the analytical results for two stormwater treatment system sampling events at [ REMOVED ]. URS collected treatment system influent and effluent water samples on February 22 and April 22, TREATMENT SYSTEM DESCRIPTION The treatment system, installed by StormwateRx in February 2012, treats both stormwater and groundwater (seepage) that enters the basement of the building. Stormwater enters the building through a drain at the base of the loading ramp located on the southeast side of the building and travels through the basement drainage system into an existing sump identified as Sump A (Figure 1). An electric sump pump with an integrated float switch pumps water from Sump A through the StormwateRx treatment system to remove polychlorinated biphenyls (PCBs). The treated effluent is plumbed back into an existing line for discharge to [ REMOVED ]. The treatment system includes an effluent flow meter and totalizer to monitor the volume of treated water. The StormwateRx treatment unit is equipped with influent and effluent sample ports for collection of water samples. SAMPLE PROCEDURES Water samples were collected from the influent and effluent sample ports by placing the sample containers under the sample port and opening the sample port valve. Each sample was collected in two 1-liter unpreserved amber glass bottles provided by the laboratory [ REMOVED ]. Stormwater quality data collected during each sampling event included measurement of the influent and effluent water temperature and ph and observation of the clarity of the water. Sample procedures and stormwater quality obervations were recorded on stormwater sample datasheets (Attachment A). Upon completion of sample collection activites, the sample containers were placed in a cooler with ice, and transported under chain-of-custody to [ REMOVED ] for analyses of PCB Aroclors by EPA Method ANALYTICAL RESULTS The influent and effluent water sample analytical results are summarized on Table 1. Representative photos of the sample ports are provided in Attachment B. Laboratory analytical reports are provided in Attachment C. Event 1 During the February sampling event, a single Aroclor (1260) was detected in the influent sample at a concentration of micrograms per liter (ug/l). Aroclors were not detected in the effluent sample above the Method Detection Limit (MDL) of ug/l. Event 2 During the April sampling event, the following three Aroclors were detected in the influent sample: Aroclor 1242 at a concentration of ug/l; Aroclor 1254 at a concentration of ug/l; Aroclor 1260 at a concentration of 2.20 ug/l. Aroclors were not detected in the effluent sample above the MDL of ug/l. Page 1

2 TOTALIZER READINGS Treatment system totalizer readings were recorded on several occasions between December, 2012 and April The following totalizer readings were recorded: December 12, 2012: acre-feet (36,500 gallons). December 19, 2012: acre-feet (38,100 gallons). January 11, 2013: acre-feet (45,900 gallons). January 24, 2013: acre-feet (54,400 gallons). February 6, 2013: acre-feet (62,900 gallons). February 22, 2013: acre-feet (63,200 gallons). April 19, 2013: acre-feet (70,400 gallons). April 22, 2013: acre-feet (70,700 gallons). SUMMARY The analytical results for the two sampling events indicate that the treatment system is removing PCBs from the water to non-detectable concentrations. [ REMOVED ] is currently planning a remedial action at [ REMOVED ] that will 1) eliminate current sources of PCBs, and 2) eliminate discharge of stormwater to the sanitary sewer, and [ REMOVED ] FIGURES Figure 1 [ REMOVED ] Drainage System and Treatment System Layout TABLES Table 1 Treatment System Analytical Results ATTACHMENTS Attachment A Stormwater Sample Datasheets Attachment B Influent and Effluent Sample Port Photograph Attachment C Laboratory Analytical Reports Page 2

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4 Table 1. Treatment System Analytical Results [ REMOVED ] Inlet Inlet-[ REM ] 2/22/2013 Event 4/22/2013 Event Outlet Inlet Outlet- [REM ] Inlet-[ REM ] Outlet Outlet- [ REM ] PCBs Aroclors (µg/l) Aroclor U U U U Aroclor U U U U Aroclor U U U U Aroclor U U J U Aroclor U U U U Aroclor U U U Aroclor U U Aroclor U U U U Aroclor U U U U Notes: J = The associated numerical value is an estimated quantity. U = The material was analyzed for but was not detected at the displayed Method Detection Limit. Detected concetrations are shown in bold. ( ( ) Page 1 of 1

5 Attachment A: Stormwater Sample Datasheets [ REMOVED ]

6 Attachment B: Influent and Effluent Sample Port Photograph

7 Influent Sample Port Effluent Sample Port Attachment B. Stormwater Rx Treatment System Showing Influent and Effluent Sample Port Locations.