Phosphorus (P) adsorption capacities of materials derived from batch experiments can vary by several orders of magnitude depending on the method used, leading to potential misinterpretation of the P retention capacity on a long-term basis and unrealistic estimations of constructed wetland systems (CWS) longevity. The objective of this study was to determine if the P saturation of the material in a column could be used for this purpose with an improved accuracy. A 278-d column experiment with a synthetic P solution was conducted to investigate the long-term P retention capacity of electric arc furnace (EAF) steel slag up to its P saturation point. EAF slag showed a high affinity for P, reaching a saturation value of 1.35 g of P kg(-1). Investigations of the regeneration of the P adsorbing capacity by this material showed that, after 4 weeks of water desaturated resting, EAF steel slag was able to increase its initial P adsorptive capacity to 2.35 g of P kg(-1). A sequential P fractionation experiment was performed to quantify the proportion of P bound to mineral compounds in EAF. From the most loosely bound to the most strongly bound P fraction, P was associated with resin extractable (14%), Fe extractable (0.5 M Na2CO3, 47%), Al extractable (0.1 M NaOH, 1%), Ca extractable (1 M HCl, 12%), and Ca in a stable residual pool (concentrated hot HCl, 26.5%). X-ray fluorescence analyses of EAF steel slag chemical composition revealed that the continuous application of a P solution resulted in 75% and 59% increases in K2O and P2O5 respectively; Al2O3 and FeO increased by 8%, while the portion of CaO remained unchanged. The investigated properties (P retention potential, regeneration of P adsorption, P fractionation) provide useful data about the suitability of slag material as a media for long-term P removal and should enable an improved prediction of the longevity of full-scale CWS.

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PurposeTo provide a comprehensive state of the art review of environmental impact assessment (EIA) of existing rapid prototyping (RP) and rapid tooling (RT), and identify prospective research needs.Design/methodology/approachThe sparse literature on the EIA of RP and RT is balanced by that of the comparatively mature field of industrial ecology (IE). Hence, the review emphasizes portable IE measurement and evaluations methods. As RP and RT can also be viewed as design tools and mass customization manufacturing, other EIA may be needed.FindingsThe scarcity of research to date combined with rapid technological advances leaves a large number of unresolved issues. In addition, the special character of RP and RT, as design and manufacturing enablers implies that future research is needed.Research limitations/implicationsThis review is drawn from a technology in rapid evolution. Hence, unresolved issues focus on technologies that already are on the market and the research needs are formulated in terms of state of the art process research.Practical implicationsAs technological advances multiply, so does the number of unresolved environmental problems. The review of unresolved issues points to a pressing need to assess the consequences of RP and RT while identified research needs point the way to anticipated areas where further assessment methods will be needed.Originality/valueThis paper intends to raise awareness about the potential environmental impacts from RP and RT, by presenting the problems associated with current methods for measuring environmental effects and discussing some of the most urgent unresolved issues, specifically with respect to materials. Indirect effects of other uses of RP and RT are discussed only briefly for lack of available data.