For more than 70 years, family-owned and operated Davis Industries Inc. has been providing scrap metal recycling services for customers in northern Virginia and Maryland. The facility in Lorton, VA, recycles aluminum, mixed steel, brass, and copper from non-working appliances, junk automobiles, and other consumer and industrial sources. The Davis Industries site operates seven cranes, an automobile shredder, shear, eddy/induction sorting system, and non-ferrous bailing system in addition to forklifts, skid steers, and excavators to assist in unloading large loads.
With so much activity taking place on a 23-acre yard and large quantities of both ferrous and non-ferrous metals being processed and temporarily stored onsite, Davis Industries was concerned about meeting facility discharge parameters for metals and suspended solids in stormwater runoff to local waterways. The facility currently operates under a National Pollutant Discharge Elimination System (NPDES) permit with the state of Virginia and is required to file a facility-generated Stormwater pollution prevention plan (SWPPP).
Upon testing, Davis Industries realized that in order to meet permit requirements, it would need to implement some additional stormwater best management practices (BMPs), including augmenting its settling pond with a more robust stormwater filtration system that would remove dirt, sediment, fine particulates, hydrocarbons, and dissolved metals from stormwater runoff.
Davis began looking into stormwater treatment systems, seeking a design that was not complicated and could meet its water-quality goals without the use of chemicals.
“Most designs from other vendors incorporated chemical treatments to remove the concentrations to our benchmark levels,” says Bill Bukevicz, executive vice president of Davis Industries. “But after looking into the various systems and design components, we determined that StormwateRx had the products that would accomplish our goals and meet our benchmark levels using physical treatment instead of chemicals.”
Davis Industries found the StormwateRx systems to offer the highest level of pollutant removal at a competitive price, while also offering the capability to be quickly and easily retrofit into the industrial site’s existing structures. With a cost-effective solution in its reach, the company decided to set its sights on installing one the most environmentally protective industrial stormwater treatment systems on the East Coast.
“We are always looking for ways to improve the efficiency and sustainability of our operations, and making sure we have the best stormwater treatment equipment is part of that commitment,” says Bukevicz. “The engineers at StormwateRx proposed a system that was innovative, yet simple to use. And the company was easy to work with and very responsive to our needs.”
Working with StormwateRx and staff, Davis Industries began implementation of new stormwater BMPs. It installed a StormwateRx treatment train consisting of a Retenu basic stormwater filtration system to remove dirt and concentrate solids, an Aquip enhanced stormwater filtration system to condition the water and remove hydrocarbons, and a Purus advanced stormwater polishing system for removal of fine particulates and dissolved metals. The StormwateRx treatment train ensures a high level of pollutant removal and water purification prior to releasing stormwater back into the environment.
The first step in Davis Industries’ stormwater treatment train was the installation of a basic industrial stormwater filtration system for stormwater pretreatment. The Retenu chemical-free treatment process uses filtered stormwater for backwashing, flushing out accumulated dirt and concentrated pollutants, before sending water back to the stormwater sedimentation pond. This process reduces the concentration of particulates in the effluent by removing solid metals and other pollutants prior to enhanced filtration.
The secondary treatment component is an Aquip enhanced media filtration system. This simple system provides efficient removal of stormwater pollutants including oils, suspended solids, turbidity, organics, nutrients such as ammonia and phosphorus, and heavy metals including copper, zinc, iron, lead, aluminum, nickel, and cadmium.
While Aquip offers a level of stormwater treatment that meets most stormwater quality standards, Davis Industries’ unique situation required a more advanced level of stormwater treatment for additional removal of dissolved metals to meet Virginia water-quality standards. The third and final element of the stormwater treatment train is a Purus stormwater polishing system. This system provides the most advanced level of stormwater treatment, removing fine particulates and turbidity to single-digit nephelometric turbidity unit (NTU) standards and removing dissolved metals down to the parts-per-billion range.
Construction and installation of the initial StormwateRx system was completed in early September 2011. Because every site is different, once treatment BMPs are installed, testing and fine-tuning of the system are done during the first series of rain events. Davis monitored seven storm events that had discharges, resulting in 96% to 76% reduction in the monitored parameters.
“As a company, we are very -impressed with StormwateRx’s professionalism and knowledge in working with their customers,” says Bukevicz. “They are proactive in helping companies like ours to meet our benchmark goals and improve our BMPs for stormwater. And the benefits to us, as a company, have been great. The StormwateRx treatment train has put Davis Industries at the forefront of environmental technology for the scrap metal recycling industry. We are proud to own one of the most environmentally protective systems on the East Coast.”
