A facility to help practitioners test the effectiveness of stormwater treatment technologies is being developed by the Oregon Department of Transportation.
The Stormwater Technology Testing Center (STTC), under construction at the Northeast Portland Maintenance Yard, is intended to provide designers and users of stormwater treatment technologies a tool to provide non-biased assessments of the effectiveness and maintainability of technologies being considered for installation at their facilities, according to Paul Wirfs, P.E., Deputy Geo-Environmental Manager.
Officials hope the new center – which is expected to open in 2017 – will help develop information on the maintainability and life cycle cost for stormwater treatment technologies that will help to protect the environment and transportation investments.
Background on Testing Center Development
State and federal agencies, together with environmental organizations, have expressed increasing concern regarding the effectiveness of stormwater treatment devices and facilities in achieving water quality standards required by permits. Transportation agencies also face ongoing concerns over maintenance costs related to stormwater treatment.
The concept for the STTC was developed by a group of stormwater professionals that ODOT convened in 2011 to discuss the challenges and ways to improve the management of large stormwater programs. The group included representatives from ODOT, other state and local agencies, and the Washington Department of Ecology (WDOE). A board has been established to provide direction on the operation of the STTC including local, state, and federal agency representatives from Oregon, Washington, and California.
Although WDOE and several other agencies had facilities or protocols established to evaluate pollution removal effectiveness of stormwater treatment devices, they could not demonstrate the capability of a long-term stormwater treatment device, the maintenance required for the technology, the costs of maintenance, and at what point the technology would fail and require replacement.
Over a two-year period between 2009 and 2011, the STTC concept was developed, including a business plan, maintainability evaluation protocols and a quality assurance project plan.
The STTC Board identified several potential sites for the center, ultimately choosing the Northeast Portland Maintenance Yard site. The site provided adequate stormwater supply and representative stormwater, an adequate facility site area with the possibility of expansion, an appropriate discharge point, and gravity flow stormwater conveyance to the testing facility. In addition, the site offered safe access and was already owned by ODOT.
Officials also noted that the STTC was one of several projects that ODOT funded to meet the commitments of a settlement agreement in response to a notice of intent to sue over alleged permit violations.
The Northwest Environmental Defense Center alleged that ODOT was not in compliance with its National Pollutant Discharge Elimination System Municipal Separate Storm Sewer Systems (MS4) permit. While that allegation was never proven, ODOT officials said the agency “chose to invest in stormwater improvement rather than on litigation.” The STTC qualified as part of that investment along with multiple other stormwater retrofit projects within the Willamette River Watershed.
The Art and Science of Stormwater Testing
The testing center consists of a combination of pumps, pipes, an air compressor, sensors and computers that work together to gather representative stormwater samples for laboratory analysis.
The STTC includes 3 “pads” or “test bays” where each technology is connected to the testing center control and piping systems. The technologies can be installed at the appropriate elevation and configuration as defined by the specifications provided by the owner of the technology. This is all located within the footprint of the STTC.
Stormwater is diverted from a 7-foot diameter drainage pipe along I‐ 205 at Columbia Slough to a large manhole called the feed wet well. A pump recirculates the stormwater and the debris in the feed wet well, allowing suction pipes to pull in a representative sample of the pollutants in the stormwater.
High-velocity vacuum samplers pull samples of the raw stormwater into jars to be sent to a laboratory for analysis. The diameter of the suction pipes, which varies from 2 inches to 4 inches depending on the pumping flow rate, ensures that flow velocity is fast enough to move sand and other debris along and carry it to the test bays. Clear PVC pipe and clear hose allow pipe-flow to be monitored, especially when leaves and sand are entering storm drains.
The process also uses a “programmable logic controller” that controls pneumatic valves in order to match the suction pipe diameter to the required pump speed. It monitors the water surface in the feed wet well and test bays with sensors to determine if too much water is being sent to the technology being tested. If the water level is rising and is about to bypass some of the raw stormwater, the programmable controller slows the dosing flow rate. All of the data regarding the water surface and flow rate are sent to a remotely operated computer program for archiving and analysis.
Ultimately, samples are sent to the laboratory, where the influent and effluent are analyzed for pollutant levels, providing data on the removal efficiency of the technology being tested.
The site is currently configured to test any type of vault, filter, or manhole shaped devices, and it can test up to three technologies simultaneously. The site also can be expanded in the future to test swales, slopes and small ponds.
“Currently, we can run the system and have made a few test runs,” according to Dan Gunther, a hydraulics engineer at ODOT. “We are still working on the software and controlling the site remotely,” he said. Testing of technologies will begin in earnest once all the software and remote controls are installed.
Quantifying Technology Costs, Maintainability
ODOT officials said the STTC will help to quantify the maintainability performance characteristics and costs of commercially ready stormwater treatment technologies. It is available to serve as a national laboratory for the professional stormwater community and will provide an unbiased and credible assessment of stormwater treatment technologies.
ODOT intends for the STTC to become a self-sufficient facility, supported by testing fees; however, financial support by owners and operators of stormwater technologies will ensure continued operation of the facility. In the future, the facility may be expanded to include additional testing bays and testing parameters such as dosing, bacteria, nitrates and more.
In terms of challenges, officials said it has taken longer than planned to obtain start-up funding and to get the facility up and running.
In that regard, states can help support the center by contributing to an ongoing Federal Highway Administration pooled fund program. A total of $300,000 is being requested to go toward business management services, calibration and testing, and data protocols. So far, a total of $125,000 has been committed, including $100,000 from Pennsylvania DOT, $15,000 from Washington State DOT, and $10,000 from the Port of Portland.
Other elements of the STTC calibration and start-up have been funded by a State Transportation Innovation Council grant from the Federal Highway Administration.
To date, ODOT has invested approximately $950,000 on the concept development and construction of the center. One more push of funding will move the project forward to full operation when testing can begin.
In addition, ODOT officials said they would like to hear from other DOTs that are interested in joining the Board or participating as a stakeholder.