The Envirogen invention provides systems and methods for removing perchlorate from water. The systems comprise reactors comprising biomass for degrading perchlorate, and the operation of the systems can be controlled according to novel logic specifications. Envirogen’s FBR is a fixed-film bioreactor in which biological media is suspended, or fluidised, 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 by-products. Over the last 15 years, Envirogen has installed and started up over 60 aerobic and anoxic FBRs throughout the United States – advancing the technology with these systems to handle a broad range of organic contaminants, as well as inorganics such as nitrate, perchlorate and selenium. Applications for Envirogen’s FBR technology range from groundwater remediation and mining water treatment to nutrient removal in wastewater and potable water production.Among the Envirogen installations currently utilizing the FBR to treat perchlorate-laden water are a major industrial groundwater remediation site in Nevada, and a California city where the Envirogen system produces municipal drinking water from perchlorate-contaminated groundwater at the city’s wells. The company has also recently announced the initiation of a FBR pilot study for perchlorate removal at a former industrial site in Israel. The California FBR system is utilising the specific patented process.