ETBE, ethyl tert-butyl ether, is an oxygenated compound used as a fuel additive to increase the octane rating and promote more efficient combustion.

The high mobility of ETBE in aquifers, combined with its limited natural biodegradability and low adsorption to the geological medium, promotes the formation of persistent plumes that are difficult to treat using conventional biostimulation or natural attenuation strategies.

ETBE and MTBE are oxygenated ethers used as fuel components. They differ in their origin, physicochemical properties, biodegradability, and behaviour in the subsurface environment.

Bioaugmentation is a biological remediation strategy based on the controlled introduction of specialised microorganisms capable of degrading specific contaminants.

Bioaugmentation introduces specialised microorganisms to enhance the system’s degradation capacity. Biostimulation promotes the activity of the microbial populations already present at the site by supplying nutrients, oxygen, or other elements required for the biological process.

Immobilisation can enhance cell retention, reduce biomass losses caused by hydraulic washout, and improve the microbiological stability and persistence of the treatment within the aquifer.

Tert-butanol, or TBA, is one of the main intermediate metabolites generated during ETBE degradation. Its evolution must be monitored to verify that the process continues through to complete degradation.

They are functional genes used as microbiological biomarkers. The ethB gene is associated with ETBE degradation processes, whereas alkB is related to the oxidation of aliphatic hydrocarbons.

Contaminant reduction is verified through hydrogeochemical monitoring and microbiological and molecular tools such as qPCR, RNA/cDNA analysis, NGS sequencing, and the quantification of functional genes associated with degradation.

The solution must be defined according to the contaminant, hydrogeological conditions, oxygen and nutrient availability, and the specific treatment objectives. Depending on site requirements, nutrients, oxygen-releasing systems, specialised biomass, and technical surfactants may be used.