Title: Introduction Text: The Navy and Department of Defense (DoD) have invested over $60 million in the development, testing, and use of innovative perchlorate treatment technologies. NAVFAC Remedial Project Managers (RPMs) should be aware of the range of perchlorate treatment options available in order to evaluate and select the best approach for their site. This Web Data Sheet provides information on perchlorate chemistry and a brief overview of perchlorate treatment technologies including biological and ion exchange treatment.

Title: Policy Text: The Department of Navy (DON) released a new policy related to Perchlorate Sampling and Management in May 2006. The policy discusses the appropriate analytical methods and also outlines the management actions to be taken if perchlorate detections occur at a site. The policy indicates that DoD has established a level of concern for perchlorate of 24 parts-per-billion (ppb) until such time that state or federal standards are promulgated. This level of concern is based on the oral reference dose for perchlorate recommended by the National Academy of Sciences (NAS) and adopted by the U.S. Environmental Protection Agency (EPA). It states that Navy policy is "to sample all sites where there is a reasonable expectation that a perchlorate release has occurred as a result of Navy activities, including sites previously analyzed by EPA Method 314.0." More definitive analytical methods than EPA Method 314.0 have recently been developed. These methods employ mass spectrometry and will provide a higher level of confidence about the occurrence of perchlorate in various environmental media at a site. Additional information is provided in the companion DoD Perchlorate Handbook.

Title: Introduction Text: Certain types of facilities may have an increased potential for perchlorate releases to groundwater. Perchlorate is used in a variety of defense and commercial applications. Ammonium perchlorate is used in most solid fuel rocket motors; ammonium and potassium perchlorate are used in munitions and pyrotechnics. There is currently no known safe or effective alternative to perchlorate for national defense uses. Perchlorate is also found in fertilizers, airbags, road flares, matches, fireworks, and lubricating oils.

Title: Introduction Text: Perchlorate is very soluble in water and exhibits low sorption onto soils. This may result in relatively large dissolved phase plumes.

Title: Introduction Text: Residual perchlorate trapped in the vadose zone or low permeability lenses may act as a long term, continuing source to groundwater.

Title: Chemistry (1 of 2) Text: Perchlorate forms when solid salts composed of ammonium, potassium, or sodium perchlorate dissolve in water. Its chemical characteristics include low volatility, low sorptivity, and high water solubility. Perchlorate is very chemically stable under aerobic groundwater conditions and can persist in the environment for decades. These properties all govern the fate and transport of perchlorate in groundwater and may lead to relatively large dissolved phase plumes at perchlorate-impacted sites.

Title: Low Volatility Text: Low volatility means that a chemical does not evaporate readily at normal temperature and pressures.

Title: Low Sorptivity Text: Low sorptivity means that a chemical tends not to be attracted to particles such as soil or organics.

Title: High Water Solubility Text: High water solubility means that a chemical readily dissolves in water.

Title: Chemistry (2 of 2) Text: Perchlorate is used in a variety of defense and commercial applications. Click here for a list of DoD munitions, munitions components, and training devices that may have contained perchlorate. Perchlorate releases may have occurred at sites where the following activities took place: The manufacture, storage, or disposal of perchlorate salts, perchlorate-containing propellants, rocket fuels, explosives, perchlorate containing munitions, munitions components, or training devices. These activities have occurred primarily at ammunition plants, arsenals, and depots. Research, development, testing, and use of perchlorate containing propellants, rocket fuels, explosives, munitions, or munitions components. Training with perchlorate containing munitions or training simulators. The DoD Perchlorate Handbook notes that "the simple fact that one or more of these activities occurred, however, should not be interpreted as evidence that perchlorate has been released." Perchlorate is also found in commercial products and releases have occurred at other non-DoD sites. Click here for a list of potential non-DoD sources. The Interstate Technology and Regulatory Council (ITRC) Perchlorate Overview document also has information on sources of perchlorate in the environment.

Title: DoD Perchlorate Sources Text: Solid fuel rockets Sea mines Torpedo warheads Smoke-generating compounds Signal flares Parachute flares Star rounds for pistols (illumination rounds) Thermite-type incendiaries Tracer rounds Incendiary bombs Fuzes Jet-assisted takeoff (JATO) devices Training simulators

Title: Non-DoD Perchlorate Sources Text: Commercial blasting (for construction) with perchlorate-containing explosives Use of perchloric acid in manufacturing processes Perchlorate-containing fertilizer Perchlorate-containing sodium chlorate used as a herbicide Commercial manufacture of perchlorate salts or perchlorate-containing items (e.g., pyrotechnics and flares)

Title: Analytical Methods Text: The DoD Perchlorate Handbook describes how to select qualified analytical laboratories and analytical methods for perchlorate. The analytical requirements for perchlorate testing will vary depending on the regulatory drivers and RPMs should secure approval from the regulatory authority for the use of the appropriate method. The selected method must be able to meet the specified method reporting limit (MRL) in the matrix of concern. Only methods employing mass spectrometry (MS) are to be used for environmental restoration/cleanup or range assessment projects. This table summarizes the recommended methods for perchlorate analysis. MS methods provide more definitive results and much lower reporting limits compared to previous methods that used ion chromatography (IC) alone such as EPA Method 314.0.

Title: Mass Spectrometry Text: Uses an instrument to identify the type and quantity of elements in a chemical substance by their mass and charge.

Title: Treatment Technologies Text: The use of conventional water treatment technologies has proven to be largely ineffective for perchlorate removal because of its low reactivity, low volatility, and high solubility. Therefore, the scientific community has made a substantial effort to develop and test more effective treatment methods for perchlorate. Many different technologies have been tested at both the pilot-scale and full-scale. Roll over the figure to see a specific list of these treatment technologies. The remainder of this Web Data Sheet focuses on biological treatment and ion exchange because these are currently the leading economically viable groundwater treatment technologies for perchlorate.

Title: Treatment Technologies Text: Continuously Stirred Reactors Packed Bed Reactors Fluidized Bed Reactors Other Reactor Types

Title: Treatment Technologies Text: Passive Delivery Systems Semi Passive Delivery Systems Active Delivery Systems Phytoremediation

Title: Treatment Technologies Text: Weak Base Anion Exchange Strong Base Anion Exchange Bifunctional Resin Ion Exchange Reverse Osmosis Nanofiltration Tailored Granular Activated Carbon Adsorption

Title: Treatment Technologies Text: Chemical Reduction Catalytic Reduction Electro/Photochemical Reduction Precipitation

Title: Treatment Technologies Text: Supercritical Water Oxidation Non-Catalytic, Hydrothermal Treatment Low Pressure Thermal Treatment

Title: Treatment Technologies Text: Unspecified Biological Treatment Methods

Title: Biological Treatment Overview Text: Biological treatment of perchlorate in groundwater can proceed relatively rapidly under the right conditions. The microbes require the presence of sufficient electron donor such as ethanol to stimulate perchlorate biodegradation. Nutrients such as nitrogen and phosphorous are also needed to sustain adequate microbial growth. These amendments can be added to enhance the biodegradation of perchlorate either in situ (i.e., below ground) or ex situ (i.e., above ground). The introduction of these amendments then allows the microbes to grow and produce enzymes. The enzymes lower the activation energy needed to reduce perchlorate to chloride and oxygen. Without an electron donor, the perchlorate molecule is typically very stable and will not be readily degraded by microbes under aerobic groundwater conditions.

Title: In Situ Biological Treatment (1 of 2) Text: Technology Description The objective of in situ biological treatment is to engineer the optimal conditions in the subsurface to promote perchlorate biodegradation. This process can be limited under normal conditions due to low pH, insufficient carbon for microbial growth, high dissolved oxygen levels, and/or the presence of nitrate because it is preferentially degraded. These limitations can be overcome through the addition of an adequate supply of electron donor to the subsurface or with pH buffering.

Title: In Situ Biological Treatment Text: Several types of electron donor sources have been reported to enhance the rate of perchlorate biodegradation. However, some of these substances have only been used in the laboratory and not in the field. Potential amendments include alcohols, fatty acids, edible oils, sugars, food wastes, or other substances.

Title: Delivery Mechanisms Text: Several methods have been proposed for the delivery of electron donor to the subsurface. Passive systems include permeable reactive barriers and unpumped wells with vegetable oil or other amendments. As shown, semi-passive systems involve injection only. Active systems include injection and extraction to recirculate electron donor in the subsurface.

Title: In Situ Biological Treatment (2 of 2) Text: The following are the primary advantages and limitations associated with in situ biological treatment: Advantages Hot spot treatment removes long-term source to groundwater Use as biobarrier to prevent off-site migration Destroys perchlorate and does not just concentrate it into a brine as with ex situ physical treatment methods Can be configured to reduce aboveground footprint May involve less capital and O&M costs compared to ex situ treatment options May also promote the biodegradation of chlorinated compounds such as PCE and TCE Limitations Number of field-scale projects limited Best suited to well-defined and shallow source areas Biofouling of injection wells can cause significant O&M issues Inefficient donor delivery can lead to little or no in situ biodegradation Low pH, high salinity, and the presence of other chemicals such as nitrate can influence the rate and extent of perchlorate degradation Can adversely impact groundwater quality such as metals mobilization, sulfide release, and methane production Regulatory approval may be needed for amendment injection

Title: Ex Situ Biological Treatment (1 of 2) Text: Technology Description Ex situ biological treatment involves extracting groundwater from the subsurface and pumping it through a reactor containing a large population of microbes. A steady supply of electron donor is pumped into the reactor to support microbial growth and the subsequent reduction of perchlorate. Roll over the figure for more information on the types of bioreactor configurations and amendments used.

Title: Ex Situ Biological Treatment Text: In the 1990s, the Air Force began testing a bioreactor for the treatment of perchlorate wastewater from the demilitarization of missiles in accordance with DoD's treaty obligations. Currently, several types of bioreactor configurations are available, including continuously stirred tank reactors (CSTRs), packed bed reactors (PBRs), fluidized-bed reactors (FBRs), and others such as hollow fiber membrane reactors. Several types of electron donors have been tested for use in bioreactors including acetate, ethanol, methanol, hydrogen gas, yeast extract, and food processing wastes.

Title: Ex Situ Biological Treatment (2 of 2) Text: The following are the primary advantages and limitations associated with ex situ biological treatment: Advantages Tested at both pilot-scale and full-scale Destroys perchlorate instead of concentrating it into a brine as with ex situ physical treatment Several bioreactor configurations have been tested at full-scale and successfully commercialized Typically less expensive in terms of O&M costs compared to physical/chemical methods Typically generates less hazardous waste than physical/chemical methods Limitations Upsets can occur from suboptimal electron donor dosing, pH changes, or other conditions Loss of biological activity could interrupt operation for several days Less conventional for drinking water applications

Title: Ion Exchange (1 of 2) Text: Technology Description Ion exchange is also an ex situ treatment technology, which involves extracting groundwater from the subsurface and pumping it through a reactor. Ion exchange removes ions from solution through sorption onto a resin. The resin eventually becomes saturated and must be regenerated. It is sometimes more cost effective to use disposable resins that can be incinerated rather than to pay to treat the regenerant brine. Several types of ion exchange resins can be used for perchlorate removal including weak base anion (WBA), strong base anion (SBA), and bifunctional resins.

Title: Ion Exchange (2 of 2) Text: The following are the primary advantages and limitations associated with ion exchange treatment: Advantages Tested at both pilot-scale and full-scale Commercially available technology Able to meet low perchlorate levels in effluent Physical treatment methods exhibit more stable operations than biological methods More widely accepted for drinking water applications Limitations O&M costs are typically high versus biological methods Not all resins are highly selective for perchlorate Other anions (e.g., nitrate, sulfate) may interfere with removal Brine treatment and disposal issues limit cost-effectiveness

Title: Other Technologies Text: There are several other physical, chemical, and thermal treatment technologies for perchlorate in groundwater. Physical Treatment Technologies. In addition to ion exchange, other potential physical treatment methods include various membrane processes and tailored granular activated carbon (GAC) adsorption. Membrane processes include treatment techniques such as reverse osmosis (RO), nanofiltration (NF), and electrodialysis (ED). All of these processes rely upon a semiporous membrane that lets water pass through, but prevents dissolved salts from penetrating the membrane. RO and NF have been reported to achieve more than 80% removal of perchlorate from process streams. With all membrane processes, the perchlorate removed is not destroyed, but collected and concentrated in a waste brine. Tailored GAC may be a future technology to remove perchlorate from existing pump and treat operations. Chemical Treatment Technologies. Potential chemical treatment methods reported in the literature for perchlorate include chemical reduction, catalytic reduction, electrochemical reduction, photochemical reduction, and precipitation. Catalysts can be used to overcome the high activation energy needed to effect perchlorate reduction. Several different types of catalysts have been tested in the scientific literature for their ability to promote the destruction of perchlorate to chloride and water. The types of catalysts tested include nickel, palladium, platinum, ruthenium, and titanium. There are several drawbacks to their use including the cost of expensive precious metals and the potential need for effluent pre-treatment to avoid catalyst fouling. Although catalysts have been employed at the field-scale to treat ion exchange brines containing perchlorate, it is unclear whether catalysts would be cost-effective as a stand-alone technology. Catalysts may be more cost effective when paired with a technology such as ion exchange or reverse osmosis that can concentrate the perchlorate influent stream therefore reducing the volume of water that must be treated in the catalytic unit. Thermal Treatment Technologies. The thermal destruction of perchlorate in solution has also been studied in the laboratory using high temperature, high pressure techniques such as super-critical water oxidation.

Title: Summary Text: The following observations can be made about perchlorate treatment technologies: Many different treatment technologies have been tested, but the leading economically viable technologies are biological and ion exchange treatment. The primary issue for in situ bioremediation is the effective delivery of amendments to the subsurface in order to achieve adequate electron donor distribution. Adequate electron donor distribution can be difficult to achieve at sites with very heterogeneous or complex soils or with deeper contamination. The full-scale use of ex situ bioreactors is feasible due to their effectiveness, reliability, and commercial development status. Ion exchange is a more conventional technology for producing potable water, but the economics of brine treatment and/or resin disposal must be evaluated.

Title: References Text: For more information, check out the following documents and/or links: Policy and Guidance DON Policy on Perchlorate Sampling and Management DoD Perchlorate Handbook General Information DoD Perchlorate Work Group Interstate Technology and Regulatory Council Perchlorate Team Defense Environmental Information EXchange (DENIX) Perchlorate Page AFCEE Perchlorate Page Sampling and Analysis Information Joint IDQTF/DoD EDQW Roundtable on the Analysis of Perchlorate in Environmental Samples Treatment Technologies Perchlorate: Overview of Issues, Status, and Remedial Options U.S. EPA CLU-IN Contaminant Focus: Perchlorate Treatment Technologies U.S. EPA Perchlorate Treatment Technology Update

Title: Contact Information Text: For more information about the Perchlorate Web Data Sheet, please contact: T2 NFESC POC (805) 982-1656 or Perchlorate NFESC POC (805) 982-1795 PRTH_NFESCT2@navy.mil