Comparison of PFAS soil remediation alternatives at a civilian airport using cost-benefit analysis

Contamination of soil and water systems by per-and polyfluoroalkyl substances (PFAS) due to uncontrolled use of aqueous film-forming foams (AFFFs) at firefighting training sites at civilian and military airports is a universal issue and can lead to significant human health and environmental impacts. Remediation of these sites is often complex but necessary to alleviate the PFAS burden and minimise the risks of exposure by eliminating the hotspot/source from which the PFAS spreads. This study presents a probabilistic cost-benefit analysis (CBA) for evaluating PFAS reme-diation alternatives, which includes monetisation of both direct costs and benefits as well as externalities. The method is applied for a case study to compare five remediation alternatives for managing PFAS contaminated soil at Stockholm Arlanda Airport in Sweden. The social profitability, or the net present value (NPV), of each remediation alternative was calculated in comparison to two reference alternatives - 'total excavation' of the site (Alt 0) or 'do nothing'. Sensitivity analyses and model scenarios were tested to account for uncertainties, including small or large PFAS spreading and simulating different values for the magnitude of annual avoided cost of inaction (i.e., aggregate benefit) from PFAS re-mediation. In comparison to total excavation, four of the five studied remediation alternatives resulted in a positive mean NPV. Excavation and stabilization/solidification of the hotspot on-site combined with stabilization using acti-vated carbon for the rest of site (Alt 2) had the highest NPV for both spreading scenarios, i.e., Alt 2 was the most so-cially profitable alternative. Simulations of the annual avoided cost of inaction enabled estimation of the breakeven point at which a remediation alternative becomes socially profitable (NPV > 0) compared to 'do nothing'. Alt 2 had the lowest breakeven point: 7.5 and 5.75 millions of SEK/year for large and small spreading, respectively

BALANCE 4P - Balancing decisions for urban brownfield redevelopment: Technical report of the BALANCE 4P project of the SNOWMAN Network coordinated call IV

Land take as a result of urbanization is one of the major soil threats in Europe. One of the key measures to prevent further urban sprawl and additional land take, is redevelopment of urban brownfields: underused urban areas with, in many cases, soil and groundwater pollution. The latter issue can be a bottleneck for redevelopment of brownfields instead of green fields. A difficulty for brownfield redevelopments is that in urban projects the responsibilities, tools and knowledge of subsurface engineering and urban planning and design are not integrated; they depend heavily on each other but work in sectors. The urban designer usually deals with opportunities for socio-economic benefits while the subsoil engineer deals with the technical challenges of the site. Balance 4P suggests a holistic approach to brownfield redevelopment that (i) recognizes all phases of the urban redevelopment process which are influenced by the planning conditions set by laws, regulations, policy and institutions; (ii) acknowledges multiple subsurface qualities in the brownfield redevelopment project; (iii) promotes knowledge exchange between the surface and the subsurface sectors, across disciplines within each sector, and over time, about the subsurface qualities of the specific project; (iv) focus on the urban redevelopment project by identifying strategies for redevelopment that can fulfil a good quality of the built environment; (v) assesses the three P’s (People, Planet, Profit/Prosperity) in each urban redevelopment phase; and (vi) puts the Process in focus rather than specific instruments by focusing on identification of WHO should be involved in the knowledge exchange process and HOW it can be mediated. The developed decision support framework is aimed to guide project teams willing to implement a more holistic approach in practice. The framework includes four steps carried out in iterative manner: (1) stakeholder analysis, (2) generation of redevelopment alternatives, (3) sustainability assessment of the alternatives, and (4) synthesis of the assessment results, including uncertainty analysis. The guidance describing the steps in the decision support framework and activities within each step can help to structure the decision process and provide support to project teams. The anticipated advantages of the holistic approach are redevelopment plans that allow for smart, cost-effective and sustainable solutions in the implementation process by making explicit use of subsurface information and knowledge in the planning process, and possibilities for more long-term sustainable planning with regard to the subsurface by increased awareness of the subsurface as a resource and the associated risks and possibilities.Environmental Technology and Desig