Biodegradation: Updating the Concepts of Control for Microbial Cleanup in Contaminated Aquifers

Abstract

Biodegradation is one of the most favored and sustainable means of removing organic pollutants from contaminated aquifers but the major steering factors are still surprisingly poorly understood. Growing evidence questions some of the established concepts for control of biodegradation. Here, we critically discuss classical concepts such as the thermodynamic redox zonation, or the use of steady state transport scenarios for assessing biodegradation rates. Furthermore, we discuss if the absence of specific degrader populations can explain poor biodegradation. We propose updated perspectives on the controls of biodegradation in contaminant plumes. These include the plume fringe concept, transport limitations, and transient conditions as currently underestimated processes affecting biodegradation.

Identification of abiotic and biotic reductive dechlorination in a chlorinated ethene plume after thermal source remediation by means of isotopic and molecular biology tools

“…Microbial oxidation might also take place, particularly in the case of cDCE and VC (Hartmans et al, 1985;Bradley andChapelle, 1998, Bradley andChapelle, 2000). Despite their presence in the subsurface, microorganisms may display a low activity, are sometimes inactive or are even dormant (Meckenstock et al, 2015), which may additionally hinder reductive dechlorination. Abiotic reductive dechlorination can also take place naturally, provided that the adequate minerals and geochemical conditions are present.…”

Organic contamination versus mineral properties: competing selective forces shaping bacterial community assembly in aquifer sediments

“…Moreover, a high load of organics switches aquifers from oxidized to reduced conditions. As such, petroleum hydrocarbons are considered key drivers of microbial community composition and dynamics (Vecht et al 1988, del Castillo & Ramos 2007, Bombach et al 2010, Meckenstock & Mouttaki 2011, Meckenstock et al 2015. Groundwater ecosystems, in particular, are generally considered low-productivity systems characterized by comparably stable environmental conditions.…”

Highly efficient pollutant removal of graphitic carbon nitride by the synergistic effect of adsorption and photocatalytic degradation

“…3b and d) can be tted into four peaks. The main peaks at 398.9 eV, 400.1 eV, and 401.1 eV correspond to the sp 2 -hybridized nitrogen in the heterocycle (C-N]C), tertiary N in the form of N(-C) 3 , and uncondensed amino functional groups (NH 2 or NH), 45,49 respectively. A weak peak at 404.5 eV of N 1s was assigned to the p / p* satellite band, which was very much like the satellite component for its C 1s signal.…”