Performance evaluation of an ex situ permeable reactive bio-barrier in phenol-contaminated water containment and remediation under a laminar flow regime
Zohreh Emmarloo, Mohsen Karrabi, Bahar Shahnavaz, Asal Masoumi Khameneh, Philippe Sechet
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引用次数: 0
Abstract
Petroleum hydrocarbons (PHCs) including phenolic compounds cause major environmental impacts just the once released into soils or groundwater. Among the core technologies, permeable reactive barriers (PRBs) have been so far exploited to contain and control such contaminants within the subsurface layers of the soil. Against this background, the present study investigated flow-biofilm interactions in a laboratory-scale permeable reactive bio-barrier (PRBB). To this end, an experimental setup was firstly built by embedding pressure measurement ports, at 10 cm intervals, onto a cylindrical column with a diameter of 57 mm and a height of 50 cm, and then filled with a porous medium, made up of sand with an average diameter of 1.78 mm. The bacterium, Pseudomonas putida (P. putida), was also utilized to generate the biofilm. Afterward, phenol-containing water was passed through the column at a rate of 2 L/h under a hydrodynamic laminar flow regime. Experimental evidence showed that the biofilm formed by bacterial growth could shrink the bio-barrier (BB) porosity from 0.35 to 0.07, instigating a drop by 590 and 840 times in the hydraulic pressure across the column at phenol concentrations, 200 and 400 mg/L, respectively. The desired biofilm additionally managed to remove 40 and 30% of phenol at concentrations of 200 and 400 mg/L, in that order. Exploring the variations in hydraulic conductivity in different layers plus the microscopic images further demonstrated that the biofilm created at phenol concentration of 200 mg/L seemed to be much stronger and even more stable, compared to the one at 400 mg/L. This was traceable to the better adaptation of P. putida to lower concentrations of phenol as the carbon source. Furthermore, the study results established that the given PRBB could help decompose only a small portion of phenol, but outperformed in terms of containing and controlling this contaminant through reducing hydraulic conductivity.
期刊介绍:
Acta Geotechnica is an international journal devoted to the publication and dissemination of basic and applied research in geoengineering – an interdisciplinary field dealing with geomaterials such as soils and rocks. Coverage emphasizes the interplay between geomechanical models and their engineering applications. The journal presents original research papers on fundamental concepts in geomechanics and their novel applications in geoengineering based on experimental, analytical and/or numerical approaches. The main purpose of the journal is to foster understanding of the fundamental mechanisms behind the phenomena and processes in geomaterials, from kilometer-scale problems as they occur in geoscience, and down to the nano-scale, with their potential impact on geoengineering. The journal strives to report and archive progress in the field in a timely manner, presenting research papers, review articles, short notes and letters to the editors.