Recent Additions

EPA-ORD's Engineering Issue Papers (EIPs) are a series of technology transfer documents that summarize the latest information on selected waste treatment and site remediation technologies and related issues and present it in a conveniently accessible manner to the user community. EIPs are designed to help remedial project managers (RPMs), on-scene coordinators (OSCs), contractors, and other contaminated sites technical staff and site managers understand the type of data and site characteristics that are needed to evaluate a technology for a specific site, as well as ways to design and optimize a technology for a particular application. This latest EIP summarizes the current knowledge on electrokinetic (EK)-enhanced in situ remediation technologies that are available for addressing contaminants in low-permeability (low-k) subsurface environments where conventional hydraulic delivery technologies often face challenges.

The updated guidance reflects the latest, best available science to provide information that managers of PFAS wastes can use to evaluate the most appropriate destruction, disposal, or storage method among those currently available.

The Federal Remediation Technologies Roundtable (FRTR) Matrix is a user-friendly tool for screening potentially applicable technologies for a remediation project. The matrix allows you to screen 49 in situ and ex situ technologies for either soil or groundwater remediation. Variables used in screening include contaminants, development status, overall cost, and cleanup time. Detailed information on each technology is also available, including direct links to the database of cost and performance reports written by FRTR members.

AMDTreat 6.0 Beta is a computer application for estimating the long-term costs of the abatement of mine drainage discharge, commonly referred to as Acid Mine Drainage (AMD). AMDTreat 6.0 Beta can assist a user in estimating costs and sizing facilities to abate water pollution, using passive or chemical treatment technologies. Treatment systems, vertical flow ponds, anoxic limestone drains, anaerobic wetlands, bioreactors, caustic soda, hydrated lime, pebble quicklime, soda ash treatment and other systems can be evaluated.

To support EPA's Per- and Poly-Fluoroalkyl (PFAS) Strategic Roadmap, the Agency is compiling and integrating a collection of data that can be used to evaluate what is known about PFAS manufacture, release, and occurrence in communities. As part of this effort, EPA is integrating data available nationally with other information from states, Tribes, and localities that are testing for PFAS pursuant to their own regulatory or voluntary data collection initiatives. The data included in the PFAS Analytic Tools have a wide range of location-specific data and, in general, are based on national scope, and readily accessible, public information repositories.

This website provides an updated spreadsheet tool developed by the EPA for estimating indoor air concentrations and associated health risks from subsurface vapor intrusion into buildings. The tool is based on the analytical solutions of Johnson and Ettinger for contaminant partitioning and subsurface vapor transport into buildings.

The Matrix Diffusion Toolkit, developed for the Department of Defense's Environmental Security Technology Certification Program (ESTCP), is a free software tool that can assist site personnel to effectively and efficiently estimate the effects matrix diffusion will have at their site, and share the results with stakeholders. The Toolkit is Microsoft Excel-based and provides the following tools to calculate and evaluate matrix diffusion effects:

• Square Root Model - this module provides planning-level estimates of the mass discharge (in units of grams per day) caused by release from a low-k diffusion-dominated unit (typically silt or clay) into a high permeability advection-dominated unit (typically sand or gravel).
• Dandy-Sale Model - this module allows users to perform contaminant transport via advection and transverse diffusion in the transmissive layer, and transport via transverse diffusion in the low-k zone. The module also provides planning-level estimates of the low-k zone and the transmissive zone.
• Matrix Diffusion Related Tools - Additional tools related to matrix diffusion are provided, including the NAPL Dissolution Calculator, Plume Magnitude Information, Low-k Zone Remediation Alternatives, and a 14-Compartment Model.

PHAST is a computer program that simulates multicomponent, reactive solute transport in three-dimensional saturated groundwater flow systems. PHAST is a versatile groundwater flow and solute-transport simulator capable of modeling a wide range of equilibrium and kinetic geochemical reactions. The flow and transport calculations are based on a modified version of HST3D that is restricted to constant fluid density and constant temperature. The geochemical reactions are simulated with the geochemical model PHREEQC, which is embedded in PHAST.

PHAST can be used in studies of migration of nutrients, inorganic and organic contaminants, and radionuclides; in projects such as aquifer storage and recovery or engineered remediation; and in investigations of the natural rock/water interactions in aquifers.

MODFLOW is a modular hydrologic model and is considered an international standard for simulating and predicting groundwater conditions and groundwater/surface-water interactions. MODFLOW programs are capable of simulating coupled groundwater/surface-water systems, solute transport, variable-density flow (including saltwater), aquifer-system compaction and land subsidence, parameter estimation, and groundwater management.

The GSI Mann-Kendall Toolkit is a free, simple, easy-to-use software tool to help environmental professionals efficiently conduct concentration trend analyses for any groundwater constituent. The tool can be used to demonstrate the plume stability condition (expanding, stable, or decreasing) and track the progress of remediation efforts, in a quantitative and consistent manner.