By Scott Love, CSR Hydro Conduit, Dallas, Texas
The City of Laredo has always been known to the residents of South Texas as "The Gateway to Mexico". Laredo is located on the historic Rio Grande River, which provides a natural border between the United States and Mexico.
Laredo is unique because it is the only city to operate international bridges between two Mexican states and the United States. With a population base approaching 200,000 people, this border town, located two hours south of San Antonio, Texas, is the second fastest growing city in the United States (primarily due to the passing of the North American Free Trade Agreement in 1994).
Unfortunately, rapid growth does not come without problems. For example, "how do you treat stormwater run-off in a rapidly expanding urban area, while protecting natural resources and not compromising economic development?"
Riazul Mia, Laredo's Environmental Manager, faced this very problem at a new US/Mexico border station being constructed in Laredo. The border station handles a large volume of international vehicle traffic between the United States and Mexico, with its stormwater run-off eventually draining into the Rio Grande River. Areas of heavy vehicle traffic, such as this, are known to be large contributors of pollution, as well as a huge potential for spills. Since vehicle maintenance is not regulated as strictly in Mexico as in the United States, concerns associated with pollutants from vehicle traffic were increased significantly.
Considering that the City of Laredo handled over $65 billion dollars in trade (equalling 38% of all ground trade between the US and Mexico), something had to be done to protect the Rio Grande from run-off pollution and potential spills at this location.
For this application, Mia decided that the Stormceptor System, from CSR Hydro Conduit, was the solution. Since the system has been proven in numerous field and lab tests to remove virtually all free oil from stormwater run-off, trap large spills, and remove up to 80% of total suspended solids (TSS), it was the logical choice for the border station.
Six STC 7200s were used within the new storm drain system to provide stormwater treatment and spill control at this large facility.
The STC 7200 is the largest Stormceptor manufactured. With the high volumes of international truck/vehicle traffic, oil storage volume was a key element in deciding which device to use on this site. Each of the STC 7200s has the ability to contain approximately 1,100 (US) gallons of oil/hydrocarbons, without risk of scouring. In addition to the large oil storage capacity, the system will hold over 700 cubic feet of sediment before requiring maintenance.
The City of Laredo decided not only to implement the use of Stormceptor at this and several locations in the city, it purchased its own vacuum truck. Since maintenance is straightforward (but often overlooked), city officials decided to take it upon themselves to ensure the long-term operation of the system.
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