Bioremediation of Chlorinated Solvents
Overview
Bioremediation uses microorganisms to degrade organic contaminants in soil, sludge, and solids either excavated or in situ. The microorganisms break down contaminants by using them as a food source or cometabolizing them with a food source. Aerobic processes require an oxygen source, and the end products typically are carbon dioxide and water. Anaerobic processes are conducted in the absence of oxygen, and the end products can include methane, hydrogen gas, sulfide, elemental sulfur, and dinitrogen gas. Ex situ bioremediation includes slurry-phase bioremediation, in which the soils are mixed in water to form a slurry to keep solids suspended and microorganisms in contact with the soil contaminants, and solid-phase bioremediation, in which the soils are placed in a cell or building and tilled with added water and nutrients. Land farming, biopiles, and composting are examples of ex situ, solid-phase bioremediation. In situ bioremediation is bioremediation in place, rather than ex situ. In situ techniques stimulate and create a favorable environment for microorganisms to grow and use contaminants as a food and energy source. Generally, this means providing some combination of oxygen, nutrients, and moisture, and controlling the temperature and pH. Sometimes, microorganisms that have been adapted for degradation of specific contaminants are applied to enhance the process.
4.29 Enhanced Bioremediation (In Situ Soil Remediation Technology)
In Remediation Technologies Screening Matrix and Reference Guide, Version 3.0. Federal Remediation Technologies Roundtable.
Biostimulation
T. Hazen.
LBNL-1691E, 23 pp, 2009
Biostimulation, the addition of nutrients to encourage the growth of indigenous contaminant-degrading microorganisms, is one of the most mature methods of bioremediation. It is applicable to both chlorinated and unchlorinated dissolved hydrocarbons. Biostimulation is dependent on indigenous organisms and thus requires that they are present and that their environment can be altered in a way that will have the desired bioremediation effect. In addition to an explanation of the concept of biostimulation, this chapter discusses critical aspects of site biogeochemistry, characterization and monitoring, combined biological technologies, and research needs.
A Citizen's Guide to Bioremediation
EPA 542-F-01-001, 2001
The Citizen's Guide Series are 2-page fact sheets that provide a general description on approaches to clean up contaminated was sites. The fact sheets cover five questions about each clean up approach: What is it?, How does it work?, Is it safe?, How long will it take?, and Why use it?.
Cometabolic Bioremediation
T.C. Hazen.
LBNL-1694E, 16 pp, 2009
Cometabolism strategies stimulate only indigenous microbes with the ability to degrade contaminant(s) and cosubstrate (e.g., methane, propane, toluene). Cometabolic bioremediation has been used on some of the most recalcitrant contaminants, such as PCE, TCE, MTBE, TNT, dioxane, and atrazine. This paper offers a brief overview of current information about methanotrophs and ammonium oxidizers.
Guía del Ciudadano para la Biocorrección
EPA 542-F-01-001S, 2001
La Serie de Guías del Ciudadano son boletines de dos páginas con datos que proveen una descripción general en cómo sanear sitios contaminados. Estos boletines con datos que cubren cinco preguntas acerca de cada procedimiento de saneamiento: ¿Qúe es?, ¿Cómo trabaja?, ¿Es seguro?, ¿Cúanto tiempo requerirá?, y ¿Por qué debe de usarse?
In Situ Bioremediation of DNAPL Source Zones
2005
This document was prepared by Lisa Moretti, a National Network of Environmental Management studies grantee, under a fellowship from the U.S. Environmental Protection Agency. The objective of this report is to provide an overview of in situ bioremediation of DNAPL source areas. This report discusses the integral steps when implementing bioremediation, such as site characterization, design considerations, and post-treatment monitoring. In addition, this report also examines the use of bioremediation as a polishing treatment for the source zone. Case studies are included as examples of the use of bioremediation as a stand-alone and a polishing treatment for DNAPL source areas.
In Situ Groundwater Bioremediation
T.C. Hazen.
Chapter 13 in Part 24 of the Handbook of Hydrocarbon and Lipid Microbiology. Springer-Verlag Berlin Heidelberg, ISBN: 978-3-540-77587-4, p 2584-2596, 2010
This paper provides an overview of bioremediation concepts involving intrinsic biodegradation, biostimulation, and bioaugmentation for a variety of contaminants, including chlorinated hydrocarbons.
