Other Recent Additions
Recent Additions
SRI Series: Aligning Remedies with Reuse: From Superfund Sites to Soccer Fields, January 25
Posted: January 13, 2012
With green space lands at a premium and communities looking for options to meet their recreational needs, some cleaned up Superfund sites are presenting a unique opportunity for development of soccer fields. EPA's Superfund Redevelopment Initiative (SRI), the U.S. Soccer Foundation and communities are working at Superfund sites to turn this opportunity into a reality. This webinar will share the stories of several Superfund sites from around the country that have been successfully redeveloped into soccer fields and how this transformation was accomplished. The U.S. Soccer Foundation, which has supported the reuse of Superfund sites as soccer fields across the Country, will share information on the webinar about resources available to communities looking to develop soccer fields. EPA will conclude the webinar by sharing tools and resources available to communities to think about future use of sites, including use as soccer fields, in the context of cleanup and long-term safety.
ESTCP Funding Opportunities for Environmental Technologies, January 24
Posted: January 13, 2012
Environmental Security Technology Certification Program (ESTCP) Director Dr. Jeffrey Marqusee will conduct an online seminar on January 24, 2012, from 1:00-2:00 p.m. Eastern Time. This "how to play" briefing will offer valuable information for those interested in new ESTCP funding opportunities. During the online seminar, participants may ask questions about the funding process, the current ESTCP solicitation, and the proposal submission process. Pre-registration for this webinar is required.
U.S. EPA Environmental Services Assistance Team (ESAT) Support
Posted: January 6, 2012
The EPA Superfund Program has historically relied on the Regional EPA Laboratories including the Environmental Services Assistance Team (ESAT) to provide non-routine analytical services in support of Agency hazardous waste site projects, and other environmental monitoring. Although primarily a Superfund vehicle, ESAT also supports the Agency's RCRA program and other non-Superfund analytical efforts. These contractors provide multidisciplinary technical teams to each Region within their respective areas. The U.S. EPA is issuing this Sources Sought Announcement (SSA) to gain knowledge of potential qualified sources and their size classifications relative to NAICS code 541380 - Testing Laboratories (size standard of $12.0M). EPA requests demonstration of capability by interested small business firms through submittal of a capability statement. In addition to the SSA, EPA requests all interested parties (whether submitting a capability statement or not) to add their company information to the "Interested Vendors List" associated with this notice on FedBizOpps.
Pg&E Topock Compressor Station, Needles, California: Revised Groundwater Corrective Measures Implementation/Remedial Design Work Plan for Swmu 1/Aoc 1 and Aoc 10
Posted: January 1, 2012
This revised corrective measures implementation/remedial design work plan presents the framework and schedule for implementation of the selected groundwater remedy for chromium in groundwater at the PG&E Topock Compressor Station. The treatment areas are designated as Solid Waste Management Unit (SWMU) 1/Area of Concern (AOC) 1, and AOC 10. The selected remedy for chromium in groundwater at SWMU 1/AOC 1 and AOC 10 near the Compressor Station combines in situ reduction with fresh-water flushing as follows:
Periodic Review: Dexter Horton Building, Facility Site Id#: 68766933, 710 2nd Avenue, Seattle, Washington
Posted: January 1, 2012
The Dexter Horton Building was at one time heated by two oil-burning boilers for which Bunker C fuel oil was stored in three underground storage tanks (USTs) buried beneath the northeastern portion of the building. When the tanks were decommissioned in 2005, petroleum-contaminated soil was encountered in the vicinity of the USTs. Groundwater was not affected. Because excavation of the USTs and soil was not feasible, in situ chemical oxidation (ISCO) treatment with hydrogen peroxide was conducted to remediate the contaminated soil in July and August 2005. The peroxide treatment reduced petroleum hydrocarbon contamination to below MTCA Method A cleanup levels of 2,000 mg/kg under the USTs; however, an estimated 85 cubic yards of shallow (0 to 6 ft bgs) fill atop the USTs and adjacent to the west basement wall still contains NWTPH-Dx compounds well in excess of the diesel-range hydrocarbon MTCA Method A soil cleanup level, up to 19,000 mg/kg NWTPH-Dx. The shallow contaminated soil is accessible for removal by excavation, but in its current state does not pose a direct contact risk because it is covered with a concrete floor slab. Subsequent soil sampling at depths below the USTs showed that the ISCO treatment had reduced TRPH concentrations in soil below the USTs from a pre-injection concentration of 18,000 mg/kg TRPH to a post-injection concentration of 400 mg/kg. A "No Further Action" letter was issued February 16, 2006, after a deed restriction was recorded with the county. Cleanup activities at this site were completed under the Voluntary Cleanup Program. Because the cleanup actions resulted in concentrations of petroleum hydrocarbons remaining at the site that exceed MTCA cleanup levels, the Washington State Department of Ecology is required to conduct a review of the site every five years.
Contamination Movement Around a Permeable Reactive Barrier at Solid Waste Management Unit 12, Naval Weapons Station Charleston, North Charleston, South Carolina, 2009
Posted: January 1, 2012
Beginning in 2000, the U.S. Geological Survey and the Naval Facilities Engineering Command Southeast investigated natural and engineered remediation of chlorinated VOC groundwater contamination at Solid Waste Management Unit 12 at the Naval Weapons Station Charleston, North Charleston, South Carolina. In early 2004, groundwater contaminants began moving around the southern end of a permeable reactive barrier (PRB) installed by a consultant in December 2002. The PRB is a barrier 130 ft long and 3 ft wide consisting of varying amounts of zero-valent iron with and without sand mixture. Contamination moving around the PRB likely has been transported at least 75 ft downgradient from the PRB at a rate of about 15 to 29 ft per year. The diversion of contamination around the southern end of the PRB may be due to construction difficulties associated with the PRB installation or to reduced permeability within the PRB. During installation of the PRB, a 110-ft-long trench originally designed to contain the PRB collapsed on November 11, 2002, ~25 ft upgradient (west) from the final PRB, and was subsequently abandoned. Guar gum with antimicrobial preservative in polymer slurry used to stabilize the abandoned trench prior to collapse was only partially recovered. Residual guar gum can cause permeability reduction in a PRB. It also is possible that permeability reduction took place within the PRB by slow degradation of the guar gum slurry or by mineral precipitation. Despite the likely permeability reduction in and near the PRB immediately following installation, there is evidence that contaminants moved through the PRB and were degraded, consistent with the barrier's planned purpose. VOC contamination in groundwater downgradient from the PRB is subject to attenuation by phytovolatilization, sorption, and biodegradation. Pulses of contamination increases have been observed in some monitoring wells downgradient from the PRB. The pulses may reflect downgradient transport of contaminant pulses; however, lateral shifting of the plume is a more likely explanation for the concentration changes at well 12MW-12S. The ability to monitor the fate and behavior of the plume in the forest is severely limited because the present axis of maximum contamination in that area bypasses all but one of the existing monitoring wells. Moreover, the 2009 data indicate no optimally placed sentinel wells in the probable path of contaminant transport; thus, the monitoring network is no longer adequate to monitor the groundwater contamination downgradient from the PRB.
Persistence of Chloroethane During Full-Scale Enhanced in Situ Bioremediation of Chlorinated Ethanes
Posted: January 1, 2012
Groundwater at a former industrial site was affected by the release of chlorinated aliphatic hydrocarbons (CAHs), including 1,1,1-TCA and related degradation products 1,1-DCA, 1,1-DCE, and chloroethane. A pilot test of enhanced in situ bioremediation (EISB) using emulsified vegetable oil (EVO) was conducted between March 2004 and November 2005. Based on successful pilot results, a full-scale injection was implemented from December 2005 to January 2006. The full-scale injection used a combination of readily degradable sodium lactate and slow-release EVO to sustain the reaction zone. Both injections were intended to stimulate anaerobic degradation of CAHs in groundwater. Semi-annual groundwater monitoring performed after the 2005-2006 full-scale injection indicated the effectiveness of EISB in reducing concentrations of 1,1,1-TCA, 1,1-DCA, and 1,1-DCE in the groundwater. Concentrations of chloroethane increased following the injections as a result of the sequential dechlorination of 1,1,1-TCA to 1,1-DCA to chloroethane. Concentrations of chloroethane generally declined after 1,1,1-TCA and 1,1-DCA were depleted, but monitoring results 28 months after full-scale injection indicated that chloroethane degradation had slowed with its concentrations still above cleanup criteria throughout the treatment zone. Geochemical data suggested that conditions suitable for the anaerobic degradation of chloroethane were diminishing, and/or a residual source of CAHs might exist in the vadose zone or capillary fringe in the source area. A second full-scale injection was performed in September and October 2008 to enhance anaerobic degradation of chloroethane. Two months later, chloroethane concentrations had increased in a portion of the source area but decreased in the majority of the treated area of the plume. In the period from 2 to 7 months after the second injection, chloroethane concentrations decreased at all locations but remained above cleanup goals. To the authors' knowledge, significant accumulation and persistence of chloroethane has not been reported at sites where 1,1,1-TCA is being remediated by EISB. Chloroethane persistence at this site is attributed to possible residual sources of parent compounds and a relatively slower degradation rate compared to 1,1,1-TCA and 1,1-DCA. Chloroethane concentrations likely will continue to decrease over time as there is evidence that the second injection further remediated residual CAH parent compounds in the source area. Monitoring data are presented to indicate the ultimate fate of chloroethane at the site.
Cyclodextrins in Bioremediation of Contaminated Soil
Posted: January 1, 2012
The efficiency of randomly methylated beta-cyclodextrin (RAMEB) used to enhance the biodegradation of transformer oil was demonstrated in both ex situ and in situ field experiments. During the in situ field experiment at a transformer station in Hungary, a combined technology (ventilation, nitrogen, and phosphorus) was implemented along with RAMEB addition, continuous removal of groundwater, continuous moisture supply (by slow infiltration of the treated water), and ex situ treatment on activated carbon. The soil was flushed with a RAMEB solution from time to time through the injection well, and after a few days' acclimation, the groundwater was pumped continuously from the extractor wells on the other side of the transformer. Continuous groundwater removal reduced the risk of spreading the RAMEB-solubilized contaminants. The period of acclimation after flushing was enough for adsorption of RAMEB on the soil, providing for a long-term effect on biodegradation. Performance monitoring was based on analysis of soil gas and groundwater. After RAMEB addition, the carbon dioxide content of the soil gas increased suddenly, indicating improved microbial activity. By the end of treatment, the hydrocarbon content of the soil decreased from ~25,000 mg/kg to <300 mg/kg. A similar combined technology was used at a former tank station on an agricultural site in Hungary contaminated with aged diesel and engine oil from leaking underground tanks. In this case, a combination of push-pull and drive-through techniques was applied: half of the additives (RAMEB and nutrients) were applied through the combined injection-extraction well, and the other half through five additional injection wells arranged around the combined well in a circle. After RAMEB addition, hydrocarbon concentrations in the extracted groundwater and the specific oil-degrading bacteria increased 10- to 40-fold and 2- to 10-fold, respectively. This application achieved a significant decrease in contaminant concentrations, from 30,000 mg/kg to 3,500 mg/kg and from >1,000 mg/L to <200 mg/L in soil and water, respectively, at the end of treatment.
Natural and Enhanced Anaerobic Degradation of 1,1,1-Trichloroethane and Its Degradation Products in the Subsurface: a Critical Review
Posted: January 1, 2012
1,1,1-Trichloroethane (TCA) in groundwater is susceptible to a variety of natural degradation mechanisms. Evidence of intrinsic decay of TCA in aquifers is commonly observed, but TCA remains a persistent pollutant at many sites. Some of the daughter products that accumulate from intrinsic decay of TCA are more toxic than the parent compound. Research advances from the past decade indicate that in situ enhanced reductive dechlorination (ERD) has promise as a cost-effective solution toward the cleanup of groundwater contaminated with TCA and its daughter products. Lab studies have demonstrated that pure or mixed cultures containing certain Dehalobacter (Dhb) bacteria can catalyze respiratory dechlorination of TCA and 1,1-dichloroethane (1,1-DCA) to monochloroethane in groundwater systems. 16S rRNA Dhb gene probes have been used as biomarkers in groundwater samples both to assess ERD potential and quantify growth of Dhb in ERD applications at TCA sites. Lab findings suggest that iron-bearing minerals and methanogenic bacteria that co-occur in reduced aquifers can affect dechlorination of TCA synergistically. Despite these advances, significant challenges remain, including an inability of any known cultures to dechlorinate TCA completely to ethane. Monochloroethane is commonly observed as a terminal product of the biological reductive dechlorination of TCA and 1,1-DCA. Also lacking are rigorous field studies that demonstrate the utility of bioaugmentation with Dhb cultures for remediation of TCA in the field. This paper offers a review of the state of the science of TCA degradation in aquifers with an examination of results from lab experiments and 22 field case studies, focusing on the capabilities and limits of ERD technology and identifying aspects of the technology that warrant further development.
Chemical Extraction of Uranium and Molybdenum From Vadose-Zone Soils and Aquifer Materials: Dam-To-Ditch Area, Cotter Uranium Mill, Canyon City, Colorado
Posted: January 1, 2012
As part of the ongoing remedial investigations for the dam-to-ditch area (DDA), Cotter has considered implementing a field-scale in situ soil flushing test to evaluate U and Mo removal from the soil. Although the batch test study originally was designed to provide reagent recommendations for use in future field-scale pilot tests for removal of U and Mo from soils in the DDA, additional characterization of total U and Mo soil concentrations found no significant source of U or Mo in the DDA soils. The batch testing study was completed in anticipation that the results could be useful in the design of future remedial systems elsewhere at the site. This report (1) provides a literature summary of chemical reagents that have been used effectively to mobilize U from contaminated soil and (2) identifies chemical reagents that can be used to extract U and Mo from soil and aquifer materials at the Cotter site.
Laboratory Study of Polychlorinated Biphenyl (Pcb) Contamination and Mitigation in Buildings, Part 1: Emissions From Selected Primary Sources
Posted: January 1, 2012
Polychlorinated biphenyls (PCBs) are a class of 209 organic compounds known as congeners, with the chemical formula of C12H10-xClx, where x is the number of chlorine atoms in the range of 1 to 10. Different mixtures of these congeners were sold under many brands and trade names worldwide, amongst which Aroclors marketed by Monsanto Company were the most common trade names in United States. Commercial production of PCBs started in 1929 and was banned by the U.S. Congress in 1978. The approximate PCB usage in the U.S. included 60% for closed system and heat transfer fluids (e.g., transformers, capacitors, and fluorescent light ballasts), 25% for plasticizers, 10% for hydraulic fluids and lubricants, and 5% for miscellaneous uses. PCBs were once used as plasticizers in caulking materials because of their compatibility with the base resin or binder. These caulking materials could contain up to 30% PCBs. Thus, all buildings that have expansion joints and that were built between the 1940s and the late 1970s are likely to contain PCBs in the caulking materials. In the past two decades, a series of field measurements conducted in Europe and North America has shown that PCB-containing caulk and sealant can be a significant source of PCBs in buildings. This report summarizes the test results for PCB emissions from primary indoor sources, with emphasis on PCB-containing caulking materials and light ballasts, and the factors that can affect the emissions. Subsequent reports will discuss the research results on PCB transport in buildings and evaluation of selected mitigation methods.
All-Time Releases of Mercury to the Atmosphere From Human Activities
Posted: January 1, 2012
Much information exists about recent releases of mercury, but little information is available on releases in the past. To find out how much impact people have had in releasing mercury to the environment over the centuries, scientists reconstructed human additions of mercury to the atmosphere (via the burning of fossil fuels, mining, and industrial processes) using historical data and computer models. Their research shows that mercury emissions peaked during the North American gold and silver rushes in the late 1800s. After a decline in the middle of the 20th century, the levels are rising again quickly, thanks mostly to a surge in coal use. Asia has overtaken Europe and America as the largest contributor of mercury. Recent data suggest that mercury concentrations in the atmosphere are declining, which is not consistent with their conclusion of increasing emissions. Changing atmospheric conditions may be partly responsible, but more work is needed, particularly to understand the fate of large amounts of mercury in discarded products like batteries and thermometers. The researchers predict mercury released from mining and fuel may take as many as 2,000 years to exit the environment and be reincorporated into rocks and minerals in Earth.
Integrated DNAPL Site Strategy: Technical/Regulatory Guidance
Posted: January 1, 2012
Restoring sites contaminated by chlorinated solvents to typical regulatory criteria (low parts-per-billion concentrations) within a generation has proven exceptionally difficult, although there have been successes. Complete restoration of many of these sites will require prolonged treatment and involve several remediation technologies. To make as much progress as possible within a generation (~20 years) requires a thorough understanding of the site, clear descriptions of achievable objectives, and use of more than one remedial technology. Making efficient progress requires an adaptive management strategy and might also require transitioning from one remedy to another as the optimum range of a technique is passed. Targeted monitoring should be used, and reevaluation should be done periodically. Managers must implement effective and adaptive treatments to address complex contamination scenarios. This guidance document was developed to assist site managers in developing an integrated DNAPL site management strategy containing five key features:
Applied Materials Building 1: Long-Term Monitoring Strategy
Posted: January 20, 2012
The Applied Materials Building 1 (AM1) Superfund site in Santa Clara, California, is the location of a former semi-conductor wafer manufacturing facility that began operations in 1974. AM1 is currently one of many sites in an area where historical industrial activities have resulted in a broad area of solvent-contaminated groundwater, mainly 1,1,1-TCA and daughter products. A 5-year review documenting the progress of AM1 toward remedial goals was completed in 2010. The site has largely achieved remedial goals for groundwater, but specific National Priorities List closeout prospects for sites with rare or intermittent exceedance of groundwater cleanup goals over a limited spatial extent are not clear. Additionally, the presence of groundwater plumes on adjacent properties could complicate the closeout decision. This report reviews historical site data and how they might support the development of a long-term closeout strategy for the AM1 site. Statistical analyses were performed using modules within the Monitoring and Remediation Optimization System (MAROS) software and ProUCL software. Several guidance documents related to closeout of sites with affected groundwater were reviewed for data collection and evaluation methods to facilitate a monitoring strategy at sites very close to attainment of groundwater standards, but no clear definition of statistical attainment standards or methods to demonstrate attainment of cleanup goals was available in the literature reviewed. As part of the review, site data have been evaluated statistically, and select results of summary statistics, trends, and data sufficiency are presented.
Tailored Granular Activated Carbon Treatment of Perchlorate in Drinking Water: ESTCP Cost and Performance Report
Posted: January 20, 2012
This demonstration project was conducted at an operating drinking water treatment plant in Fontana, California, where a perchlorate plume at least 6 miles long affects water supplies in four towns. Two field test installations were implemented, the first consisting of three vessels in series treating 38 gallons per minute (gpm) (0.14 m3/minute) and the second consisting of six smaller-scale treatment trains treating 1.5 gpm (0.0057 m3/minute). The tailored granular activated carbon (TGAC) system removed perchlorate effectively to below current regulatory standards for ~15,000 bed volumes (BVs) per bed (4- to 5-month bed life). TGAC successfully achieved the perchlorate concentration reduction objective for a total treated volume of ~30,500 BVs with two beds in series. Data from the two different scales of testing suggest that increases in nitrate and perchlorate influent concentrations reduce breakthrough time. Increases in the concentrations of other anions appear, at worst, to decrease performance only moderately. The cost analysis conducted in this project suggests that TGAC currently is not able to displace conventional, perchlorate-selective IX resins economically. Conventional wellhead technologies are specific for perchlorate only and are unable to treat VOC co-contaminants effectively, but in this study, TGAC removed perchlorate and TCE simultaneously, with breakthrough and saturation occurring sooner (8 to 22% sooner for breakthrough) in the TCE-spiked system than in the control system.
Evaluation of Alternative Causes of Widespread, Low Concentration Perchlorate Impacts to Groundwater: Phase II Report
Posted: January 20, 2012
SERDP Project ER-1429 funded a study to estimate the potential impacts of historic and current use of Chilean nitrate fertilizers on soil and groundwater quality at two different tobacco research stations in North Carolina. Baseline analysis of soil and groundwater samples at each of the research stations failed to detect perchlorate, indicating that past Chilean nitrate fertilizer applications at these sites are not causing long-term perchlorate impacts. Analysis of soil and groundwater samples following application of a currently-available Chilean nitrate fertilizer (potassium nitrate) also failed to detect perchlorate, in large part because the amount of perchlorate in the newer available products is orders of magnitude lower than the perchlorate content of the historical Chilean nitrate fertilizer products. While the results of this study do not demonstrate perchlorate impacts to soil and groundwater from past or current fertilizer applications conclusively, monitoring of nitrate applied as a perchlorate surrogate suggests that the potential exists/existed to affect groundwater at some sites, depending on site-specific factors. Further research is needed to gain a better understanding of the potential long-term impacts of historical Chilean nitrate fertilizer application on groundwater systems.
Probability of Detecting Perchlorate Under Natural Conditions in Deep Groundwater in California and the Southwestern United States
Posted: January 20, 2012
Data from 1,626 groundwater samples collected in California, primarily from public drinking water supply wells, were studied to investigate the distribution of perchlorate in deep groundwater under natural conditions. The wells were sampled for the California Groundwater Ambient Monitoring and Assessment Priority Basin Project. Researchers develop a logistic regression model for predicting probabilities of detecting perchlorate at concentrations greater than multiple threshold concentrations as a function of climate (represented by an aridity index) and potential anthropogenic contributions of perchlorate (quantified as an anthropogenic score—AS—a composite categorical variable). The model includes terms for nitrate, pesticides, and VOCs. The incorporation of water-quality parameters in AS permits identification of perturbation of natural occurrence patterns by flushing of natural perchlorate salts from unsaturated zones through irrigation recharge as well as addition of perchlorate from industrial and agricultural sources. The data and model results indicate low concentrations (0.1 to 0.5 µg/L) of perchlorate occur under natural conditions in groundwater across a wide range of climates, beyond the arid to semiarid climates in which they mostly have been previously reported. The probability of detecting perchlorate at concentrations >0.1 µg/L under natural conditions ranges from 50 to 70% in semiarid to arid regions of California and the Southwestern United States, and to 5 to 15% in the wettest regions sampled (the Northern California coast). The probability of concentrations above 1 µg/L under natural conditions is low (generally <3%).
The 10th International Conference On Mercury as a Global Pollutant (Icmgp), Halifax, Nova Scotia, July 24-29, 2011
Posted: January 20, 2012
The ICMGP was initiated in Gavle, Sweden, in 1990 and now is the preeminent international forum for discussion of science and policy issues related to mercury in the environment. The ICMGP series is held every two to three years. With recent meetings attracting many hundreds to over a thousand conferees, this meeting is the venue to present exciting and novel findings and to hear about the most recent and important advances in mercury research. Each ICMGP carries with it a theme that is intended to provide a forward-thinking topical focus. The theme for the 2011 meeting was "Air, Land, Sea, and Me." This forum was designed for exploration of the linkages among mercury sources to the environment, terrestrial and aquatic mercury transport and fate processes, and health risks associated with exposures of humans and wildlife to mercury. Current issues such as climate change and new regulatory frameworks were key topics for presentation and discussion. The presentation abstracts are available on the website through the Final Technical Program:
Permeable Reactive Barriers & Reactive Zones &Mdash; PRB /Rz 2010: Proceedings of the 4th International Symposium, Antwerp, July 6-8, 2010
Posted: January 20, 2012
Permeable reactive barriers (PRBs) and reactive zones (RZs) are recognized technologies for the in situ improvement of groundwater quality. Both technologies aim to realize in situ stimulation of pollutant removal processes to prevent further migration of pollution. This symposium brought together pioneers and experts from all over the world to exchange information and new experience. The final conference of the MULTIBARDEM LIFE project (LIFE06 EBV/B/000359) was integrated into the PRB/RZ-symposium. MULTIBARDEM demonstrated multibarriers at pilot scale for different applications and geological situations.
Spreadsheet-Based Modeling of ISCO With Permanganate
Posted: February 1, 2012
CDISCO, a Microsoft Excel spreadsheet-based model, can be used to assist with the design of in situ chemical oxidation (ISCO) systems that use permanganate (MnO4-). The model inputs are the aquifer characteristics (porosity, hydraulic conductivity, effective aquifer thickness, natural oxidant demand, kinetic parameters, contaminant concentrations), injection conditions (permanganate injection concentration, flow rate, duration), and unit costs for reagent, drilling, and labor. Permanganate transport in the aquifer is simulated and used to estimate the effective radius of influence (ROI) and required injection-point spacing. CDISCO then provides a preliminary cost estimate for the selected design conditions. The user can perform multiple runs of CDISCO to optimize the cost of the ISCO design. Comparisons with analytical and numerical models of nonreactive and reactive transport demonstrate that CDISCO accurately simulates permanganate transport and consumption. Comparison of CDISCO results with 3-D heterogeneous simulations show that aquifer volume contact efficiency and contaminant mass treatment efficiency are closely correlated with the ROI overlap factor. The spreadsheet, user's guide, and training video are available on line:
