Experimental investigations and numerical modelling of in-situ reactive caps for PAH contaminated marine sediments

Abstract

The present study compared numerical modelling and experimental investigations to evaluate the effectiveness of in-situ reactive capping for marine sediments contaminated by polycyclic aromatic hydrocarbons (PAHs). As a case study, sediment samples from Mar Piccolo (Italy) were analyzed and experiments were undertaken using batch columns. Two types of capping amendments were tested: AquaGate® + 5% of powdered activated carbon (AG PAC) and Organoclay Reactive Core Mat (OC RCM). The column tests were carried out for 20 days, obtaining a short-term PAH distribution for three cases analysed, which compared the application of the two caps with no intervention. In parallel, in order to evaluate the intervention long term efficacy, an ad-hoc multilayered model predicting PAH concentrations into the sediments and the overlying water column was developed and validated with the experimental results. Both capping systems considerably reduced PAH concentrations in the overlying water, with the highest performance seen in AG PAC for benzo[a]pyrene (99%) and anthracene (72%); results also confirmed in the model predictions. In addition, the numerical simulations indicated a good efficiency of both caps over time, obtaining PAH values below the threshold limit in the long term. Although further experiments need to be developed accounting for multiple contamination competitiveness.

Remediation of a Petroleum Hydrocarbon-Contaminated Site by Soil Vapor Extraction: A Full-Scale Case Study

“…Common remediation technologies employ a range of physical, chemical, biological treatments, and thermal approaches [4][5][6]. Among the in-situ technologies, soil vapor extraction (SVE) has gained in efficiency and popularity for volatile (VOC) and semi-volatile organic compound (SVOC) removal [7].…”

A review of the in-situ capping amendments and modeling approaches for the remediation of contaminated marine sediments

“…2c) between two geotextile layers (Fig. 2b), by further reducing ISC total layer thickness to about 1 cm (Meric et al, 2014b;Bortone et al, 2020). It includes additional benefits such as uniform consolidation, defined mass per area, and drainage.…”

“…on the top of contaminated sediments. Several field and bench-scale capping applications are presented in literature (Cornelissen et al, 2012;Park et al, 2018;Bortone et al, 2020), demonstrating how ISC controls contamination in sediments and, subsequently, to the overlying water. The main advantages of an ISCbased remediation can be summarized as (i) relatively lower costs compared to other sediment remedial technologies (Lofrano et al, 2017), (ii) suitability for sequestering both organic and inorganic pollutants (Sharma and Reddy, 2004), and (iii) all the intrinsic advantages of being an in-situ technique, such as the reduction of resuspension phenomena (Ting et al, 2020).…”

Ecological Response in the Integrated Process of Biostimulation and Bioaugmentation of Diesel-Contaminated Soil

“…Several methods are widely used for soil remediation, such as vapor treatment [11,12], chemical treatment [13,14], physical remediation [15][16][17] and bioremediation [18,19], etc. Among these, bioremediation techniques have drawn growing attention due to their cost-effectiveness and non-invasiveness [20][21][22][23][24].…”