Fate of Chlorinated Benzenes in Laboratory Peat and Pozzolana Filters

Abstract

The removal of chlorinated benzenes (CBs) from the compartments and from polluted industrial sites is of great public interest for the decontamination of polluted water and for the protection of the environment. Biological degradation could be considered as a feasible process to eliminate these compounds from the environment as soil or groundwater. A research program in progress since the year 2007 was initiated to investigate the capacity of eco-remediation of CB-contaminated groundwater using a pilot-scale subsurface flow constructed wetland. In order to assess the removal efficiency of these compounds and to evaluate the biological activities, column experiments were performed. The fate of three CBs was investigated by feeding spiked tap water through laboratory columns filled with two different solid-state materials: peat and pozzolana. In order to stimulate biological activity, organic matter coming from aged vertical flow constructed wetland was added to the media.Concentrations of CBs in water effluent and in air and biological activities were monitored during 4 months. At the end of the experimental period, CB concentrations in the depth of columns were determined and a mass balance was calculated for the CBs. Removal efficiencies of the laboratory columns were >98% in the peat columns and situated around 87% to 95% in the pozzolana columns, indicating the suitability of the experimental systems for the removal of CBs. Higher effluent CB concentrations from the pozzolana columns were detected. Concentration of CBs in ambient air indicates that volatilization was low. ATP monitoring, reduction of tetrazolium violet, and exopolysaccharide determination indicated considerable biological activity with variations according to column depth and carrier material.

Potential of anthracite, dolomite, limestone and pozzolan as reactive media for de-icing salt removal from road runoff

“…Hence, increased porosity may enhance fragmentation in the medium and long term during hot-cold, wet-dry and freeze-thaw cycles. Pozzolan showed the largest porosity (57 %), consistent to previously reported (Cottin and Merlin 2010), followed by limestone (22 %), and ultimately by dolomite (4 %). So it can be inferred that dolomite presents the best physical properties for minimizing fragmentation processes, followed by limestone.…”

“…Natural pozzolan is a black or red igneous rock whose porosity and cellular texture confers a high potential retention capacity. Pozzolan has been traditionally employed as building material (in cement and concrete), but it has revealed high suitability for removing Cl ions (Al-Rawajfeh et al 2013) and chlorinated benzenes (Cottin and Merlin 2010).…”

Lab-Scale Performance Evaluation of Vertical Flow Reed Beds for the Treatment of Chlorobenzene Contaminated Groundwater

“…Biofiltres were contaminated with 3 CBs (pollutants at higher concentrations found in the polluted groundwater studied). Mass balance was determined in order to assess the fate of these pollutants in this system [13].…”

“…Different filling materials were used:  An inorganic material:pozzolana that is a lavastone  Two organic materials: peat and green compost. These filling materials differ in term of porosity, density, hydraulic conductivity and organic carbon content [13]. Organic and inorganic materials have very different physicochemical properties ( Table 2).…”

“…Pollutants were extracted from a sample volume of 100 mL of aqueous effluents and analysed using solid phase extraction (SPE) and HPLC methods [13]. At the end of the experiments, CB concentrations at different depths of columns were determined by Soxhlet extraction.…”