Envirogen Technologies recently announced it has been awarded a contract by American Pacific Corporation (AMPAC) to provide a large-scale fluidized bed bioreactor (FBR) system for the biodegradation of perchlorate and other constituents from groundwater in the area of a former manufacturing facility in Henderson, Nevada. The 1.2-million-gallons-per-day-capacity system will replace a smaller biological-based system in operation since 2006 and use Envirogen’s patented FBR technology in a custom configuration to reduce influent concentrations of perchlorate to non-detectable levels prior to surface discharge. Currently in the design phase, the new treatment system is scheduled for startup in December 2011.

According to Robert Stark, south region vice president for Envirogen, this latest project underscores increasing industry awareness and acceptance of the FBR as a reliable and environmentally sustainable solution to groundwater remediation needs. “This innovative green technology continues to distinguish itself as the best answer to heavily perchlorate-laden groundwater in both remediation and drinking water applications. In this instance, we are targeting perchlorate as the primary contaminant but can remove both chlorate and nitrate with the same process,” Stark says. “With a number of installations providing trouble-free operation over the past 13 years, the FBR’s benefits are well proven. These systems are designed to provide robust treatment in a small footprint with acceptable waste rates and reduced energy and chemical consumption. The technology’s flexibility to handle multiple constituents and varying flow characteristics also bodes well for its potential to treat other significant emerging contaminants such as selenium, hexavalent chromium, or chlorinated solvents,” he continues. According to Joseph Carleone, president and CEO of AMPAC, “We are very pleased with the Envirogen equipment, which treats organic waste streams at our Sacramento facility, and look forward to working with them on our Henderson, Nevada, project.”

Perchlorate is a highly soluble anion used in the manufacture of solid rocket propellant, fireworks, road flares, explosives, and other products. Envirogen’s FBR is a fixed-film bioreactor in which biological media is suspended, or fluidized, within the reactor vessel by the upward flow of water through the system. The suspended media provides a large surface area for microbial growth and allows a biomass density several times greater than that of other bioreactor designs under similar loading conditions. Microorganisms in the reactor completely destroy influent perchlorate and other targeted contaminants under anoxic conditions, without generating hazardous waste byproducts.

The new system being designed and built for AMPAC by Envirogen will consist of three FBRs and an H-120 biofilter for odor control. The facility will remove up to 500 parts per million (ppm) of perchlorate in the groundwater to non-detectable levels and, depending on the load, treat up to 800 gallons per minute. Envirogen will also provide installation oversight and customer support through the training and startup phases of system implementation.

According to Jeff Gibson, vice president and chief technical officer of AMPAC, the choice of FBR technology comes after a thorough technical evaluation. “Based on our experience since 2006 with a smaller, full-scale in-situ biological-based technology, we chose the ex-situ biologically-based fluidized bed reactor technology because it should allow us to achieve remedial goals that have changed since 2005. Working with the State of Nevada, Division of Environmental Protection, we believe we have formulated a plan to use the Envirogen FBR technology in a manner beneficial to the State of Nevada over the long term,” he says.

Headquartered in the Houston suburb of Kingwood, Texas, Envirogen designs, builds and implements systems for business in municipal and industrial water and environmental treatment applications. A primary focus for Envirogen is the concept of lifecycle performance, in which the company provides guaranteed, pay-for-performance, long-term contracts at predictable costs that offer customers the lowest total cost over the lifetime of an equipment installation. Primary applications for Envirogen’s systems include treatment of groundwater for the delivery of high-quality potable water, groundwater remediation, wastewater treatment, water re-use, nutrient removal, and odor and VOC control for municipal and industrial markets. In industrial markets such as mining, hydrocarbon processing, and chemical processing, Envirogen also specializes in process water treatment, byproduct recovery and chemical purification. The company conducts business throughout the United States, with regional offices in Southern California, Illinois, New Jersey and Tennessee. For more information on the company, visit www.envirogen.com.