| Marjol Battery Site |
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Stormwater Management System
In order to control stormwater at the Site both during and after construction
activities and to keep sediment (small soil particles that are carried along in
water) on the Site and out of the Lackawanna River, a basin and other drainage
features such as check dams and swales were constructed as outlined in the USEPA/PADEP-approved
100% Design Plan for the Site (Click here for more information on the
Final 100% Remedial Design Plan). The stormwater management system consists
of several items
STORMWATER
SAMPLING AND DISCHARGE
The 100% Design Plan calls
for stormwater from the clean areas of the Site to be collected in the new
temporary sediment basin. Sediment that is carried along with the stormwater
settles out in the basin, and stormwater collected in the basin is released to
Sulphur Creek under a permit issued by the State of Pennsylvania. During
construction of the Final Remedy at the Site, the drainage system is designed so
stormwater falling on contaminated areas of the Site does not flow into the
basin, but is retained within the contaminated areas by berms. If there is not enough space
for all of the water to be held within the contaminated areas, however, the
design provides for the potentially contaminated water to also drain to the
sediment basin. Since lead sticks to the sediment, as long as the sediment is
kept on the site by allowing it to settle out of the water in the basin, the
water can be safely discharged to the river. This sediment can then be easily
excavated and placed into the Containment Area before the final cap is
installed. In this way, the water is managed so that the lead remains on the
site by controlling where the sediment goes. Sampling of the basin
discharge is included in the 100% Design Plan and became part of the state
permit. The design requires stormwater from the basin to be sampled as it is
being discharged into Sulphur Creek until the areas draining to the basin have
grass growing on them. The basin stormwater sampling plan consists of the
following: If the skimmer has been raised so that it does not
discharge water (for example, if there is a concern that contaminants
may have entered the basin), then the basin water is checked to see if
the turbidity is above the performance standard of 250 NTUs. If it is
above 250 NTUs, then a flocculant (i.e. Pond Clear) is added to the
water to get the soil particles to drop to the bottom leaving clear
water at the surface. Once the turbidity is below 250 NTUs, the skimmer
is lowered and the basin water discharges through the skimmer.
(Click here for a picture
of the skimmer in the discharge position.) CONTAINMENT (CAP) AREA OVERFLOWS As a result of heavy rains in July and August, 2009, water overflowed the Containment (cap) Area (CA) (which has contaminated material in it) into a drainage feature (the South Swale) outside of the CA and into the basin on July 31, August 10, and on August 12, 2009. While every effort has been made to keep this type of overflow from occurring, the possibility of it happening was considered in the design, and so the overflow water flowed into the sediment basin as it is supposed to do where the lead contaminated sediment could settle out before the water is discharged. Tests conducted after the overflows show that the discharges were well below the limits that were set by the State to protect the Lackawanna River. When each of the overflow incidents has occurred, the skimmer in the basin has been raised (if it wasn’t already) to prevent the flow of water from the basin through the discharge channel. Water in the basin was tested for turbidity and when it was below the performance standard, the skimmer was lowered to allow water to discharge. After the overflow in July, the basin water was also tested for total and dissolved lead. Any sediment and battery casings that have floated onto the CA berm and into the swale were removed and placed back into the CA. XRF analysis (an XRF is a portable instrument used for testing lead concentration in substances such as soil) for lead has been performed on the berm and in the swale to see if the overflow contaminated any previously clean areas. If the soil lead levels were above the cleanup level, then soils on the berm and swale were excavated and placed into the CA. The excavated areas were rechecked with the XRF to be sure lead levels were below the cleanup standard. After the
first overflow, a meeting was held to discuss how to better control an overflow
if it happened again. In order to get more room to hold the contaminated water
so that it would not go off-site, it was decided to pump the contaminated water
from the CA to a strip pit that was previously excavated – Area B – instead of
back into the CA as the practice had been. Area B will be tested near the end of
the project and will be re-excavated if necessary with any contaminated material
being placed in the CA and solidified. Subsequent efforts after the overflows
focused on making sure that the pumps were ready when rain occurred during the
night and that the pumps could handle all of the water. While the overflows are
not what we would like to see, the important point is that the lead is being
contained within the site as it is supposed to be while we are managing the
water as best we can with the unfavorable weather we have been having.
STORMWATER DISCHARGE ABOVE THE PERFORMANCE STANDARD - JANUARY 25, 2010
As required when significant rain events occur, on January 25, 2010, AGC
and SCE personnel conducted an Erosion and Sedimentation Control Inspection at
the Marjol Site. During the inspection, they noticed that the water leaving the
basin had much more sediment in it than normal. In taking the daily turbidity (a
measurement of the cloudiness of the water which is caused by sediment) reading,
(click here for Stormwater
Sampling and Discharge information), the water was found to have a sediment
load well above the performance standard: 1785 NTUs when it is supposed to be
below 250 NTUs. Upon investigating , they observed that the skimmer head had
separated from the skimmer arm and the arm dropped below the surface of the
basin allowing sediment-laden water from the bottom of the basin to be
discharged through the outlet structure.
STORMWATER DISCHARGE ABOVE THE PERFORMANCE STANDARD - MARCH 14, 2010 As required when significant rain events occur, on March 14, 2010, AGC personnel conducted an Erosion and Sedimentation Control Inspection at the Marjol Site. The water in the basin and the discharge from the basin was turbid. A turbidity (a measurement of the cloudiness of the water which is caused by sediment) reading was taken for the water being discharged. (Click here for Stormwater Sampling and Discharge information). The water was found to have a sediment load well above the performance standard: 1275 NTUs when it is supposed to be below 250 NTUs. AGC pulled the skimmer to stop discharge from the basin. SCE was called to the Site and applied Pond Clear in the basin and the discharge channel (to cause the sediments to drop out of the water). A leak was found in the outlet structure so water was still able to discharge but at a much slower rate and at a much decreased volume. After the Pond Clear was added, the discharge turbidity dropped to 205 NTUs. The high flows of water in the discharge channel had blown out the silt fence and silt socks at the fence line, so SCE also placed additional silt socks outside the fence in a U-shape. When AGC left the Site on March 14, 2010, the turbidity levels in the discharge channel had dropped to 195 NTUs.
Water
samples (one for total lead and one for dissolved lead) were collected from
the discharge point and were sent to the laboratory for analysis. Dissolved
lead was not
detected at a detection limit of 1 ug/L. The NPDES
permit standard for maximum dissolved lead for the Site is 650 ug/L. The
total lead result is 18.2 ug/L. There is not an NPDES standard for total
lead, but the total lead result will be compared to the turbidity levels and
then to the dissolved lead result. The very low total and dissolved lead
results provide reassurance that even though the turbidity levels were above
the performance standard, there was NOT a release of lead from the site that
would affect the creek or the river.
SCE worked on March 15 and 16, 2010 to repair the leak in the outlet structure. Once the outlet structure is repaired, the discharge channel will be allowed to drain and then repairs will be made to the silt fence and silt socks. Hay bales were also placed on March 15, 2010. A turbidity reading was collected at the discharge point on March 15, 2010; the result was 223 NTUs. EPA, DEP, and Throop Borough were notified of the situation on March 15, 2010. Lackawanna County Conservation District was also notified. As is required, a non-compliance report was submitted to PADEP on March 19, 2010. (Click here to review the Non-Compliance Report.) The skimmer was lowered back down on March 16, 2010 to allow water from the basin to drain as it is designed to do. Turbidity readings after the skimmer was lowered were as follows: 11:30 am - 124 NTUs 11:40 am - 71.8 NTUs
STORMWATER DISCHARGE ABOVE THE PERFORMANCE STANDARD - MARCH 30 and 31, 2010
Over 1.5 inches of rain was received on March 30, 2010. The skimmer had been flipped to prevent water from leaving the basin. (Click here for Stormwater Sampling and Discharge information) When SCE and AGC representatives checked the Site in the evening during the rain event, there was flow coming from the discharge pipe due to a leak in the skimmer arm. AGC took a turbidity reading at the discharge point and the result was 77.5 NTUs at 7:30 pm. (Turbidity is a measurement of the cloudiness of the water which is caused by sediment.) The basin had filled up to the point of almost going over the baffle, so AGC representatives flipped the skimmer to allow water to discharge from the basin. Shortly after flipping the skimmer, AGC checked the turbidity at the discharge point. The turbidity was 330 NTUs at 8:45 pm. The turbidity level is supposed to be below 250 NTUs for discharge, so AGC flipped the skimmer back into the closed position to stop water from flowing into the discharge channel. There continued to be some flow in the channel due to the leak in the skimmer arm. On March 31, 2010, a turbidity reading was collected at the discharge point at 8:45 am. The turbidity result was 330 NTUs. A turbidity reading of 324 NTUs was collected at the discharge point at 9:30 am after additional BMPs (hay bales) were added in the channel outside the fence. Turbidity at the confluence of the discharge channel and Sulphur Creek was checked as well. Two turbidity readings were taken at this location: one was 152 NTUs and the other was 158 NTUs. This demonstrated that while compliance with the performance standard was not achieved at the discharge point, it was met before the water entered Sulphur Creek. As requested by AGC, SCE plugged the skimmer orifice inside the outlet structure around the skimmer orifice plate. Once the plug was in place, flow into the discharge channel was reduced by approximately 90%. AGC observed that by approximately 1 pm, all flow in the discharge channel had stopped. Water samples (one for total lead and one for dissolved lead) were collected from the discharge point and were sent to the laboratory for analysis. The dissolved lead result was 4.4 ug/L. The NPDES permit standard for maximum dissolved lead for the Site is 650 ug/L. The total lead result was 33.9 ug/L. There is not an NPDES standard for total lead, but the total lead result will be compared to the turbidity levels and then to the dissolved lead result. The very low total and dissolved lead results provide reassurance that even though the turbidity levels were above the performance standard, there was NOT a release of lead from the site that would affect the creek or the river. The skimmer and orifice were repaired during the week of April 5, 2010, to prevent further leaks into the structure. EPA, DEP, and Throop Borough were notified of the turbid discharge. As is required, a non-compliance report was submitted to PADEP on April 6, 2010. (Click here to review the Non-Compliance Report.)
Daily Stormwater and Sediment Data and Information – May 2010 Click on the shaded dates (the numbers) below to view turbidity data, stormwater discharge data and XRF sediment testing data available for those days. (Note: Turbidity data is only collected on days when the basin is discharging or following an overflow of the Containment Area. Collection of samples of stormwater discharge for laboratory analysis is required monthly and has also been performed when overflows have occurred. Sediment sampling has taken place when overflows have occurred.) No testing was performed and therefore no data are available for the dates that are not shaded. (There has been no flow from the basin into the discharge channel and therefore no turbidity readings collected for the period from April 1, 2010 through June 4, 2010.) Incidents such as the Containment Area (CA) Overflow are noted on the calendar. Copies of the reports regarding the overflows are provided on the calendar pages for those dates.
Page Last Modified Friday June 04, 2010 11:44:31 AM
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