Facility Components
Please click the points on the rendering below to learn about the various components of the STTC facility. Click here to download a PDF copy of the diagram.
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Feed Wet Well
Stormwater is diverted from the 7-foot drainage pipe to a large manhole called the Feed Wet Well (FWW). The diversion structure and wet well were an existing features on the STTC site which a previous project had abandoned. A pump recirculates the stormwater and the debris in the FWW so that the suction pipes always collect in a representative sample of the pollutants in the untreated stormwater into the Control Center and Test Bays. Piping in the FWW delivers stormwater to the STTC’s Test Bays via gravity flow or pumping. The diameter of the pipes vary from 2” to 4”, depending on the desired flow rate and ensures flow velocity is fast enough to keep larger sediment and other debris is suspension as it is carried to the Test Bays. Clear PVC pipe and hoses are used so flow can be visually monitored and easily identify needed repairs.
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Weather Station
Several weather stations have been installed within the watershed for collecting meteorological data. This information will be used to inform the STTC when rainfall events will provide appropriate runoff for testing operations. It collects precipitation, barometric pressure, humidity, temperature, and wind speed and direction. Stations are located: adjacent to the STTC control room, at Portland International Airport and approximately two miles northwest of the STTC, and on the Glisan Street exit 21A sign (I-205).
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Air Compressor & Tank
The 50 HP Rotary Screw Air Compressor provides 229 cubic feet per minute of compressed air at 125 pounds per square inch to a 660-gallon air tank. The compressed air is used to power the four (4) Air Operated Double Diaphragm Pumps and Seventeen (17) Air Operated Pinch Valves.
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Air Operated Double Diaphragm
PumpsAir Operated Double Diaphragm (AODD) Pumps are chemically clean, rugged, easy to repair. Clear PVC pipe and hoses are used so flow can be visually monitored and easily identify needed repairs.
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Programmable Logic Controller (PLC)
The Programmable Logic Controller (PLC) performs three key tasks:
- It controls Pneumatic Valves in order to match the suction pipe diameter to the pump speed that will produce the required velocity in the pipes for keeping sediment in suspension.
- It also monitors the water surface in the Test Bays with Guided-Wave Level Sensors. These sensors determine if too much water is being sent to the stormwater treatment technology being tested. If the water level is rising and the technology is about to go into bypass, the PLC slows the dosing flow rate to the technology.
- It sends data for the tasks it performs and all the water surface and pump flow rate data to the Supervisory Control and Data Acquisition (SCADA) program for archiving and analysis. The SCADA system allows the operators of the STTC to remotely monitor and control the air compressor, weather stations, multiple stormwater pumps, flow control valves, and samplers at the facility.
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Vacuum Samplers
Vacuum Samplers pull samples of the raw stormwater into sample-jars. High velocity streams of water are necessary during the sampling process to suspend and carry sediment to the sample-jars. Influent and effluent stormwater samples are then sent to a laboratory for analysis. Data from laboratory analysis of the pollutant concentrations in these samples are used to determine the removal efficiency of the stormwater treatment technology being tested.
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Control Center
The Control Center houses key components of the STTC including the air-operated diaphragm pumps, vacuum samplers, programmable logic controllers, and Supervisory Control and Data Acquisition (SCADA) system.
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Test Bays
Each of the three Test Bays can be provided stormwater from the Feed Wet Well via gravity flow or pumping. The gravel pads allow for easily installing each stormwater treatment technology to the appropriate elevation in accordance with the technology providers specifications. Guided-Wave Level Sensors are installed on the technology to communicate with the Programmable Logic Controller (PLC) and allow the system to provide the correct amount of flow. Sampling of the effluent occurs prior to discharging to the open manholes which lead to the Columbia Slough.
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Expansion Area
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Additional Test Bays may be added to the north of the existing facility to increase the testing capacity or to add bays suitable for testing SCMs with unique geometric configurations. In the future, the STTC could be used to test for pollutants and contaminants not included in the stormwater provided by the contributing watershed by adding a dosing chamber. The STTC Board of Directors currently has only approved the testing of commercially ready SCMs. Future STTC operations could also include expanding the scope of services to include research applications.