Removal of mixture ofcis-1,2-dichloroethylene/trichloroethylene/benzene, toluene, ethylbenzene, and xylenes from contaminated soil byPseudomonas plecoglossicida

Abstract

BACKGROUND This study focused on the simultaneous removal of BTEX (benzene, toluene, ethylbenzene, and xylenes) and CAHs (chlorinated aliphatic hydrocarbons, represented by cis‐DCE (cis‐1,2‐dichloroethylene) and TCE (trichloroethylene) mixture from soil, using an indigenous BTEX‐adapted bacterium identified as Pseudomonas plecoglossicida. CAHs can be aerobically cometabolized by microbial oxygenases induced during the bacterial growth on such primary substrates as toluene and ortho‐xylene. RESULTS The bioremoval extent of BTEX/CAHs mixture varied, depending on the experimental conditions. As the ratio of BTEX to CAHs concentration was changed from 4 to 20, the bioremoval of both BTEX and CAHs decreased. The increase of initial BTEX concentration, from 200 to 1000 ppm, increased the microorganism lag phase and correspondingly prolonged the bioremoval process but decreased the bioremoval efficiency. The cometabolism of CAHs, when toluene and/or BTEX were provided as growth substrate, was significantly higher compared with other treatments without toluene. The BTEX/CAHs mixture removal between sterile and non‐sterile soils revealed removal by the inoculant to be the major removal mechanism for the mixture. CONCLUSION A mixture of BTEX, cis‐DCE, and TCE in soil was simultaneously removed by P. plecoglossicida under aerobic conditions. The results obtained help to enhance the applicability of bioremediation technology to mixed wastes contaminated sites. © 2013 Society of Chemical Industry

Bioremediation: Perspectives of the use biopolymers systems for slow release nutrients

“…In a double coat system with crosslinked starch, as an outer layer and ethylcellulose (EC), as the inner layer, the modified cellulose provided to the system a better balance on the hydrophilic and biodegradable properties of the starch (19). Another case of double coating is diatomite (outer layer), fossil material formed by the deposition of algae, and xanthan gum reticulated with epichlorohydrin (inner layer), in which the higher crosslinking density of the material allowed the better release of urea after 28 days (79%) (116).…”

Combined Removal of an MTBE and BTEX Mixture Using Indigenous Microbe Immobilized on Waste Silica Gel

“…The most toxic components in petroleum products, with potential mutagenic, teratogenic, and carcinogenic activities, include such monoaromatic compounds as benzene, toluene, ethylbenzene, and three isomers (ortho-, meta-, and para-) of xylene, collectively known as BTEX. They are also widely used as industrial solvents for organic synthesis and equipment cleansing and are easily seep into groundwater [1]. BTEX compounds are of significant environmental concern and are listed as priority pollutants by the United States Environmental Protection Agency (US EPA) because of their toxic and carcinogenic effects on humans [2].…”