Optimization Model for the Design of Multi-layered Permeable Reactive Barriers

Abstract

Abstract. Permeable reactive barriers (PRBs) are employed as in situ groundwater remediation technology. The installation of PRBs is usually a major investment, where one of the biggest cost drivers are material costs. PRBs are barriers against contaminants moving under the natural gradient, however not against groundwater contaminants. The most common construction of a PRB is a single barrier, but in the case of contaminant mixtures a multi-layered construction, i.e. a combination of different reactive materials and removal processes, is required. The most important parameters for PRB design are dimensions. The barrier must be long enough to treat the entire width of the plume (dimension perpendicular to groundwater flow) and should extend to and be keyed into an impermeable layer. The problem is to determine the optimal thickness of a PRB, which should provide a residence time appropriate for reducing the concentration of contaminants to the desired effluent concentration. In PRBs, design is accomplished using numerical methods or simulators, which are useful to predict the scenarios and evaluate the resulting groundwater flow systems to specific site conditions. On the other hand, numerical methods are complicated and may have significant errors if the discretization is too coarse or is incorrectly aligned. This paper deals with a simple, conceptual model of a one-approach optimization method for multi-layered PRB design. Based on literature and laboratory test results (residence time, density and hydraulic coefficient), a selection of layers of reactive materials was determined. Considering the lowest cost of the reactive materials, the required thicknesses of activated carbon, zeolite and zero valent iron were calculated using two different algorithms. The simple model may be used for preliminary barrier design and cost calculations. Using the optimization model in a preliminary design stage, it is possible to reject the PRB concept and avoid losing time for the complicated analysis.

Funnel and Gate Permeable Reactive Barrier Configuration for Contaminated Groundwater Remediation – Designing, Installation, and Modeling: A Review

“…The hydrogeologic (groundwater movement), geochemical (chemical reactions), and economic components of the system all require modeling (construction and operational costs). Numerical approaches, on the other hand, are complex and can result in considerable mistakes if the discretization is too coarse or the alignment is incorrect [82].…”

New Composite Sorbent for Removal of Sulfate Ions from Simulated and Real Groundwater in the Batch and Continuous Tests

“…Removing (or at least controlling) the source of contamination represents a significant step that must be applied before the remediation process. The cleanup can be achieved by one of the following methods [ 2 , 3 ]: containment of contaminants, pump and treat, stabilization/solidification, air stripping and natural attenuation. In addition, the permeable reactive barrier (PRB) method was presented as an alternative for treatment of polluted subsurface water and results of many studies proved that this method is effective and efficient in the reclamation of groundwater.…”

An optimized configuration of adsorptive wells for the remediation of an aquifer contaminated by multiple aromatic hydrocarbon pollutants

“…In this contest, Permeable Reactive Barriers (PRBs) are a well-regarded passive technique for groundwater remediation, on behalf of their high efficiency, low operating and maintenance costs, especially when dealing with high volume aquifers and low pollutant concentrations (Luo et al, 2016;Bortone et al, 2013a;Powell et al, 1998). Various studies have demonstrated, by comparing PRB with P&T, a 40-70% cost saving for groundwater remediation from chlorinated hydrocarbons over extended time periods (Polonski et al, 2017;Reeter et al, 1999).…”