Contaminated environments in the subsurface and bioremediation: organic contaminants

Abstract

Due to leakages, spills, improper disposal and accidents during transport, organic compounds have become subsurface contaminants that threaten important drinking water resources. One strategy to remediate such polluted subsurface environments is to make use of the degradative capacity of bacteria. It is often sufficient to supply the subsurface with nutrients such as nitrogen and phosphorus, and aerobic treatments are still dominating. However, anaerobic processes have advantages such as low biomass production and good electron acceptor availability, and they are sometimes the only possible solution. This review will focus on three important groups of environmental organic contaminants: hydrocarbons, chlorinated and nitroaromatic compounds. Whereas hydrocarbons are oxidized and completely mineralized under anaerobic conditions in the presence of electron acceptors such as nitrate, iron, sulfate and carbon dioxide, chlorinated and nitroaromatic compounds are reductively transformed. For the aerobic often persistent polychlorinated compounds, reductive dechlorination leads to harmless products or to compounds that are aerobically degradable. The nitroaromatic compounds are first reductively transformed to the corresponding amines and can subsequently be bound to the humic fraction in an aerobic process. Such new findings and developments give hope that in the near future contaminated aquifers can efficiently be remediated, a prerequisite for a sustainable use of the precious subsurface drinking water resources.

Isolation, Identification and Degradation Characteristics of Oil Degrading Bacterial Strain

“…Release of hydrocarbon into the environment whether accidentally or due to human activities is a main cause of water and soil pollution [1] [2]. Soil contamination with hydrocarbons causes extensive damage of local system since accumulation of pollutants in animals and plant tissue may cause death or mutations [3].…”

Review: Microbial biocenoses in pristine aquifers and an assessment of investigative methods

“…Anderson and Lovley 1997;Hohener et al 1998;Holliger et al 1995;Hunkeler et al 1999;Puhakka et al 2000;Thomas and Ward 1992).…”

Influência do biodiesel de soja na biodegradação anaeróbia do benzeno e tolueno

“…Dentre os diversos processos que influenciam no destino de contaminantes, a biodegradação predomina no ambiente subsuperficial (KAO et al, 2010;BATTLE-AGUILAR et al, 2009;FRASER et al, 2008;FERIS et al, 2008). A elevada demanda bioquímica de oxigênio exercida pela presença de contaminantes orgânicos torna as condições do meio predominantemente anaeróbias (MACKAY et al, 2006;FERIS et al, 2008;CORSEUIL et al, 2011a;CORSEUIL et al, 2011b), fazendo com que processos anaeróbios assumam um papel de considerável importância para a biorremediação de diversos contaminantes (RAMOS et al, 2013;KLEINSTEUBER;SCHLEINITZ;VOGT, 2012;FARHADIAN et al, 2008;HOLLIGER et al, 1997), apesar de possuírem um potencial inferior de transferência de energia em relação aos processos aeró-bios (CHAPELLE, 2001). …”