A brief outline of the development of bioremediation technologies is presented. The major features and limitations are discussed, and an overview of the current state of the art in field applications is sketched.

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Bioremediation. An overview

Biogeochemistry of landfill leachate plumes

Nitrate attenuation in groundwater: a review of biogeochemical controlling processes.

Nanoscale zero-valent iron: Future prospects for an emerging water treatment technology

Hundreds of millions of litres of petroleum enter the environment from both natural and anthropogenic sources every year. The input from natural marine oil seeps alone would be enough to cover all of the world's oceans in a layer of oil 20 molecules thick. That the globe is not swamped with oil is testament to the efficiency and versatility of the networks of microorganisms that degrade hydrocarbons, some of which have recently begun to reveal the secrets of when and how they exploit hydrocarbons as a source of carbon and energy.

Marine microorganisms make a meal of oil

Many hydrocarbons and related organic contaminants are rapidly degradable in the presence of oxygen. Unfortunately, exchange of oxygen with subsurface contaminant plumes is often slow. In this paper, equations are developed for simulating the simultaneous growth, decay, and transport of microorganisms, as well as the transport and removal of hydrocarbon and oxygen. These equations are solved by conventional numerical techniques to study the impact of microbial kinetics, horizontal mixing, adsorption, and vertical exchange with the unsaturated zone on biodegradation. In the region near the hydrocarbon source, any available oxygen will be rapidly consumed. In the body of the hydrocarbon plume, oxygen transport will be rate limiting and the consumption of oxygen and hydrocarbon can be approximated as an instantaneous reaction. The major sources of oxygen to the plume appear to be transverse mixing, advective fluxes when adsorption is significant and vertical exchange with the unsturated zone. In a companion paper (R. C. Borden et al., this issue), hydrocarbon transport is simulated at a hazardous waste site where oxygen-limited biodegradation is known to occur.

Transport of dissolved hydrocarbons influenced by oxygen‐limited biodegradation: 1. Theoretical development

Several forms of biological treatment can be used to treat contaminated aquifers. In situ treatment increases the activity of the indigenous organisms by the addition of nutrients and electron acceptor. Withdrawal and treatment technologies rely on removal of the ground water and any of several wastewater treatment processes to biodegrade the organics. Addition of acclimated or genetically engineered organisms may overcome the time necessary for acclimation to the contaminants, but requires that the added population establish itself in the environment and be able to locate and continue to degrade the compounds of interest at what are often very low concentrations. Most of these techniques utilize aerobic organisms, but the potential for treatment with anaerobic organisms exists. Mathematical models that include biological decay terms are useful tools in the design and evaluation of biological treatment options. Biological treatment techniques are a valuable tool for the restoration of contaminated aquifers.

Biorestoration of aquifers contaminated with organic compounds

Introduction In Situ Bioremediation of Soils and Ground Water Contaminated with Petroleum Hydrocarbons Bioventing of Petroleum Hydrocarbons Treatment of Petroleum Hydrocarbons in Ground Water by Air Sparging Ground-Water Treatment for Chlorinated Solvents Bioventing of Chlorinated Solvents for Ground-Water Cleanup through Bioremediation In Situ Bioremediation Technologies for Petroleum Derived Hydrocarbons Based on Alternate Electron Acceptors Bioremediation of Chlorinated Solvents Using Alternate Electron Acceptors Natural Bioremediation of Hydrocarbon-Contaminated Ground Water Natural Bioremediation of Chlorinated Solvents Introduced Organisms for Subsurface Bioremediation

Handbook of Bioremediation

1,4-Dioxane is classified as a probable human carcinogen. It is used as a stabilizer for chlorinated solvents, particularly, 1,1,1-trichloroethane (TCA), and it is formed as a by-product during the manufacture of polyester and various polyethoxylated compounds. Improper disposal of industrial waste and accidental solvent spills have resulted in the contamination of groundwater with 1,4-dioxane. Volatilization and sorption are not significant attenuation mechanisms due to 1,4-dioxane's complete miscibility with water. At present, advanced oxidation processes (AOPs) are the only proven technology for 1,4-dioxane treatment. 1,4-Dioxane was believed to be very resistant to both abiotic and biologically mediated degradation due to its heterocyclic structure with two ether linkages. However, recent studies have shown that 1,4-dioxane can be biodegraded as a sole carbon and energy source, and that cost-effective biological treatment processes can be developed. Future work should be oriented towards the developme...

Occurrence and Treatment of 1,4-Dioxane in Aqueous Environments

Three-dimensional field monitoring of a gasoline plume showed rapid decay of toluene and ethylbenzene during downgradient transport with slower decay of xylenes, benzene, and MTBE under mixed aerobic-denitrifying conditions. Decay was most rapid near the source but slower farther downgradient. Effective first-order decay coefficients varied from 0 to 0.0010 d−1 for MTBE, from 0.0006 to 0.0014 d−1 for benzene, from 0.0005 to 0.0063 d−1 for toluene, from 0.0008 to 0.0058 d−1for ethylbenzene, from 0.0012 to 0.0035 d−1 for m-, p-xylene, and from 0.0007 to 0.0017 d−1 for o-xylene. Laboratory microcosm studies confirmed MTBE biodegradation under aerobic conditions; however, the extent of biodegradation was limited.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/97WR00014

Robert C. Borden

Papers

Transport of dissolved hydrocarbons influenced by oxygen‐limited biodegradation: 1. Theoretical development

Biorestoration of aquifers contaminated with organic compounds

Handbook of Bioremediation

Occurrence and Treatment of 1,4-Dioxane in Aqueous Environments

Intrinsic biodegradation of MTBE and BTEX in a gasoline‐contaminated aquifer