| Title | Bioaugmentation With a Consortium of Bacterial Sodium Lauryl Ether Sulfate-Degraders for Remediation of Contaminated Soils |
| Abstract | The anionic surfactant sodium lauryl ether sulfate (SLES) is the main component of most commercial foaming agents (FAs) used in the excavation of highway and railway tunnels with Earth pressure balance-tunnel boring machines (EPB-TBMs). Several hundreds of millions of tons of spoil material, consisting of soil mixed with FAs, are produced worldwide, raising the issue of their handling and safe disposal. Reducing waste production and reusing by-products are the primary objectives of the "circular economy," and in this context, the biodegradation of SLES becomes a key question in reclaiming excavated soils, especially at construction sites where SLES degradation on the spot is not possible because of lack of space for temporary spoil material storage. The aim of the present work was to apply a bacterial consortium (BC) of SLES degraders to spoil material excavated with an EPB-TBM and coming from a real construction site. For this purpose, the BC capability to accelerate SLES degradation was tested. Preliminary BC growth, degradation tests, and ecotoxicological evaluations were performed on a selected FA. Subsequently, a bioaugmentation experiment was conducted; and the microbial abundance, viability, and SLES concentrations in spoil material were evaluated over the experimental time (0.5, 3, 6, 24, 48, and 144 h). Moreover, the corresponding aqueous elutriates were extracted from all the soil samples and analyzed for SLES concentration and ecotoxicological evaluations with the bacterium Aliivibrio fischeri. The preliminary experiments showed the BC capability to grow under 14 different concentrations of the FA. The maximum BC growth rates and degradation efficiency (100%) were achieved with initial SLES concentrations of 125, 250, and 500 mg/L. The subsequent bioaugmentation of the spoil material with BC significantly (sixfold) improved the degradation time of SLES (DT50 1 day) compared with natural attenuation (DT50 6 days). In line with this result, neither SLES residues nor toxicity was recorded in the soil extracts showing the spoil material as a by-product promptly usable. The bioaugmentation with BC can be a very useful for cleaning spoil material produced in underground construction where its temporary storage (for SLES natural biodegradation) is not possible. |
| Source | Frontiers in microbiology 12 |
| Keywords | anionic surfactantfoaming agentsspoil materialbioremediationunderground constructionbacterial consortium |
| Journal | Frontiers in microbiology |
| Editor | Frontiers Research Foundation,, Lausanne, Svizzera |
| Year | 2021 |
| Type | Articolo in rivista |
| DOI | 10.3389/fmicb.2021.740118 |
| Authors | Rolando, Ludovica; Caracciolo, Anna Barra; Grenni, Paola; Mariani, Livia; Rauseo, Jasmin; Spataro, Francesca; Garbini, Gian Luigi; Visca, Andrea; Patrolecco, Luisa |
| Text | 461944 2021 10.3389/fmicb.2021.740118 ISI Web of Science WOS 000704513700001 anionic surfactant foaming agents spoil material bioremediation underground construction bacterial consortium Bioaugmentation With a Consortium of Bacterial Sodium Lauryl Ether Sulfate Degraders for Remediation of Contaminated Soils Rolando, Ludovica; Caracciolo, Anna Barra; Grenni, Paola; Mariani, Livia; Rauseo, Jasmin; Spataro, Francesca; Garbini, Gian Luigi; Visca, Andrea; Patrolecco, Luisa CNR; CNR; Tuscia Univ The anionic surfactant sodium lauryl ether sulfate SLES is the main component of most commercial foaming agents FAs used in the excavation of highway and railway tunnels with Earth pressure balance tunnel boring machines EPB TBMs . Several hundreds of millions of tons of spoil material, consisting of soil mixed with FAs, are produced worldwide, raising the issue of their handling and safe disposal. Reducing waste production and reusing by products are the primary objectives of the circular economy, and in this context, the biodegradation of SLES becomes a key question in reclaiming excavated soils, especially at construction sites where SLES degradation on the spot is not possible because of lack of space for temporary spoil material storage. The aim of the present work was to apply a bacterial consortium BC of SLES degraders to spoil material excavated with an EPB TBM and coming from a real construction site. For this purpose, the BC capability to accelerate SLES degradation was tested. Preliminary BC growth, degradation tests, and ecotoxicological evaluations were performed on a selected FA. Subsequently, a bioaugmentation experiment was conducted; and the microbial abundance, viability, and SLES concentrations in spoil material were evaluated over the experimental time 0.5, 3, 6, 24, 48, and 144 h . Moreover, the corresponding aqueous elutriates were extracted from all the soil samples and analyzed for SLES concentration and ecotoxicological evaluations with the bacterium Aliivibrio fischeri. The preliminary experiments showed the BC capability to grow under 14 different concentrations of the FA. The maximum BC growth rates and degradation efficiency 100% were achieved with initial SLES concentrations of 125, 250, and 500 mg/L. The subsequent bioaugmentation of the spoil material with BC significantly sixfold improved the degradation time of SLES DT50 1 day compared with natural attenuation DT50 6 days . In line with this result, neither SLES residues nor toxicity was recorded in the soil extracts showing the spoil material as a by product promptly usable. The bioaugmentation with BC can be a very useful for cleaning spoil material produced in underground construction where its temporary storage for SLES natural biodegradation is not possible. 12 Published version Frontiers_2021 INTERNATIONAL PAPER Frontiers_2021.pdf Articolo in rivista Frontiers Research Foundation, 1664 302X Frontiers in microbiology Frontiers in microbiology Front. microbiol. Frontiers in microbiology MARIANI LIVIA ROLANDO LUDOVICA GARBINI GIAN LUIGI VISCA ANDREA luisa.patrolecco PATROLECCO LUISA anna.barracaracciolo BARRA CARACCIOLO ANNA paola.grenni GRENNI PAOLA francesca.spataro SPATARO FRANCESCA jasmin.rauseo RAUSEO JASMIN |
