This laboratory test was conducted using soil samples taken directly from a detention pond on a construction site. The purpose of the test was to determine treatment levels and removal efficiency for inclusion in Soil Erosion and Sediment Control Regulations as an accepted Portable Sediment Tank (PST) technology, particularly as it pertains to construction jobsite runoff.
Location
Challenges
Victoria Estates stormwater detention pond contains water that is dense with yellow clay, fine silt, and sand. While it is representative of most construction job sites, Starr Water Treatment Systems staff intentionally sampled dry, flaky soil that was heavily coated in residue. We wanted to examine our System’s ability to reduce turbidity and remove TSS from the most challenging soil on the site.
Procedure
Starr Water Treatment Systems crew arrived at Victoria Estates in Neptune, NJ and removed one, five-gallon drum of construction soil for testing. The soil was removed with a metal shovel directly from the dry basin. The drum was then taken back to the Aqualete Testing Facility.
Prior to the test, the WTS2000 was set up in the testing space. The System’s top hatches were removed in order to observe and directly interact with the components. To begin, the system was filled with water. This was achieved via pump connected to a circuit. Water entered the first chamber, flowed through to the second chamber, and through to the third chamber.
After the system was filled with water, the first scoop of sand was added. This scoop was collected at the influent and labeled. Another sample taken in the same manner was collected at the system effluent after the water had enough time to pass through the entire system to ensure any sand from the initial dumping would make it all the way through. Each sample obtained was recorded in a log with time and location.
A generous amount of sand was added to the chamber one influent pipe. Another sample was collected at each chamber’s influent pipe, and then another sample was collected at the system effluent pipe. Over the course of the testing, an entire five gallon drum of sand was added to the system. After it was added, another round of samples was taken in each the first, second, and third chambers. The samples were marked and logged and placed in a cooler at approximately 4 degrees centigrade and later sent to independent lab for testing.
Once the final sample was taken, the pump was turned off. The trays were observed for sediment collection and retention. The WTS2000 was drained and cleaned.
Results
It was determined that the WTS2000 removes virtually all of the sediment particles from the water at a flow rate of 80 gallons per minute. The amount of sand collected by the first chamber was considerable. Very few silt and sand particles passed into the second chamber and virtually no debris entered the third chamber. The WTS2000 is effective in minimizing the effects of soil erosion and controlling sediment on construction sites. Additionally, results from samples collected and tested at an independent laboratory showed the following results:
- Total Suspended Solids (TSS) - 92 %
- Turbidity (NTU) - 94 %
- Final Turbidity 66NTU
Benefits
By treating collected runoff, the WTS2000 prevents TSS and sediment from polluting nearby waterways. The sediment collected within the unit may also be reclaimed for use on the site. The WTS2000 minimizes negative water quality impacts that result from post-construction runoff from site work in both new development and redevelopment applications.
