Brett Cohen

Containment of chromium and zinc in ferrochromium flue dusts by cement-based solidification

Abstract A physico-chemical model is proposed for the immobilisation of soluble metal species contained in cement-based solidification products where the primary constituent is a ferro-alloy flue dust. Particular attention has been given to the fate of chromium — in both Cr(III) and Cr(VI) forms — and zinc. Whilst metal retention can be achieved by a combination of physical and chemical processes, experimental work has shown that the alkaline nature of the cementitious product pore solution reduces the solubility of Cr(III) and zinc species to retard their mobility. Cr(VI) remains mobile over the likely pH range. Effective setting of the cement-waste product requires a preliminary wash of the untreated dust to remove much of this soluble chromium and other salts. The permeability of the final product is much reduced by effective cross-linking of cement hydration products within the aggregate pore spaces. This inhibits liquid migration through the cement-waste product and assists in physically containing residual Cr(VI), Cr(III), Zn and Mg.

Lessons from co-impacts assessment under the Mitigation Action Plans and Scenarios (MAPS) Programme

The MAPS Programme has been active in Brazil, Chile, Colombia and Peru in supporting the development of an evidence base to inform the processes involved in climate mitigation policy-making. The programme combines detailed quantitative analysis with an extensive stakeholder engagement process to provide policy and decision makers with the information required for long-term climate mitigation planning. In recognition of the critical need to consider the developmental context and agenda in climate policy-making, the projects undertaken in these countries have experimented with various types of assessments of developmental impacts at both the macro and micro levels. These impacts have been collectively termed co-impacts to reflect the fact that these may be either positive or negative. In this article the value and challenges associated with co-impacts work for climate mitigation policy are considered. The value of including co-impacts analysis in the MAPS processes included increased stakeholder buy-in, making the case for mitigation action, informing INDCs and the prioritization of particular mitigation actions. Challenges include those associated with obtaining locally relevant data, the selection and operation of appropriate macro-economic models and analytical approaches and working with multidisciplinary teams. The article concludes by making some suggestions to optimize co-impacts work, through reference to other bodies of literature. The authors highlight that this article is situated within a dominant approach to climate mitigation policy work in developing countries, which implicitly places the non-climate benefits of any action as secondary to the primary benefit of climate change mitigation and constructs an artificial separation of policy formulation and implementation. Practitioners are encouraged to reflect on the implications of these considerations in future efforts. Policy relevance One of the primary challenges to advancing climate mitigation policy in developing countries is that of perceived relevance: near-term development priorities are overwhelming. Identifying, understanding and engaging with the co-impacts of mitigation actions has emerged as one way of addressing this challenge. Although still at an experimental phase, experience with co-impacts analysis in the MAPS countries provides some useful lessons in how to develop this area of work.

Multi-criteria decision analysis in policy-making for climate mitigation and development

Greenhouse gas (GHG) mitigation policy-making has largely been conducted in isolation of development considerations. An emerging literature, bolstered by the “nationally determined” nature of the Paris Agreement, explores the identification and assessment of the co-impacts of mitigation actions. There is now a recognized need to consider mitigation an integral part of a multi-objective development challenge. However, the literature on how to practically and effectively apply this in policy-making, particularly in developing economies, is limited. This paper explores the potential for using approaches that fall under the umbrella of multi-criteria decision analysis (MCDA) in guiding analyses and policy-making that relate to the climate mitigation–development interface. It categorizes three distinct types of decision problems in the broad area of climate and development policy-making, and presents lessons from three case studies, in India, Chile, and Peru and Colombia taken together, where aspects of MCDA approaches were explored. Based on these reviews, the paper concludes that MCDA approaches, despite certain limitations, can add substantive and procedural credibility to existing toolkits supporting climate and development decision-making. Key contributions of the approach are to structure the analyses, systematically include stakeholder deliberations, and provide tools to rigorously incorporate quantitative and qualitative co-impacts in multiple objective-based decisions.