Influence of flow rate and particle size on local equilibrium in column percolation tests using crushed masonry
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Column leaching tests are frequently used and accepted for investigation of release of hazardous substances from solid materials. Independent of differences due to the field of application or national regulations, column tests assume that local equilibrium is established in the experiment which facilitates transfer of results to field conditions. In the process of harmonization and standardization within Europe the question on the influence of flow rate and grain size distribution on the local equilibrium was raised. Thus, a set of experiments using two different masonry materials with varying grain size distribution and flow rate were conducted including stop/flow experiments. Results are compared to a numerical model which takes intraparticle pore diffusion-controlled release of Mo and V into the percolating water into account. Due to the relatively high intraparticle porosity of the materials (24–29%) data and model indicate that initially equilibrium-state conditions prevail followed by rapidly decreasing concentrations. The model fits data for Mo and V reasonably well; however, after the initial decline of concentrations (at L/S > 2) extended tailing is observed especially of elements occurring as oxides, which is not captured by the model.
KeywordsLeaching Porosity Stop/flow experiments Intraparticle diffusion model Vanadium Molybdenum
Free samples of masonry were provided by the manufactures. We thank Gabriele Christoph, Renate Helm, Katja Nordhauß and Peter Walzel for technical assistance as well as Annett Zimathies and Carsten Prinz for porosity measurements. This work was partly funded by CEN/NEN in the framework of project No 11810594. We are thankful for the constructive cooperation within the project with Ole Hjelmar (project leader) and André van Zomeren. The authors acknowledge the support by Deutsche Forschungsgemeinschaft (DFG)—Germany under the Grant 281741268 (SFB 1253) and by Umweltbundesamt (UBA)—Germany under the Grant FKZ 371374228/2.
- 10.Hjelmar O, Hyks J, Wahlström M, Laine-Ylijoki J, van Zomeren A, Comans R, Kalbe U, Schoknecht U, Krüger O, Grathwohl P, Wendel T, Abdelghafour M, Mehu J, Schiopu N, Lupsea M (2013) Robustness validation of TS-2 and TS-3 developed by CEN/TC351/WG1 to assess release from products to soil, surface water and groundwater, Final report https://www.nen.nl/web/file?uuid=e56cca92-7959-4885-bc3b-d803f5692e7a&owner=37da2561-2ebf-4eef-87d6-f5a4c1760a25. Accessed 5 June 2018
- 19.CEN/TS 16637-3: 2016-12 Construction products—assessment of release of dangerous substances—Part 3: horizontal up-flow percolation testGoogle Scholar
- 24.Ogata A, Banks RB (1961) A solution of the differential equation of longitudinal dispersion in porous media, U.S. Geol. Surv. Prof. Papers, 411-AGoogle Scholar
- 26.Finkel M, Liedl R, Teutsch G (2002) Modelling reactive transport of organic solutes in groundwater with a lagrangian streamtube approach. In: Deutsche Forschungsgemeinschaft (DFG) (ed) Geochemical processes: conceptual models for reactive transport in soil and groundwater. Research Report. Wiley‐VCH, Weinheim, Germany, pp 115–134CrossRefGoogle Scholar
- 33.Lopez Meza S, Kalbe U, Berger W, Simon F-G (2010) Effect of contact time on the release of contaminants from granular waste materials during column leaching experiments, vol 30. Waste Management, New York, pp 565–571Google Scholar
- 36.Garrabrants AC, Kosson DS, Kariher RD, Seignette P, van der Sloot PFAB, Stefanski HA, Baldwin LM (2012) Interlaboratory validation of the leaching environmental assessment framework (LEAF) Method 1314 and Method 1315, in: Agency, U.E.P. (Ed.)Google Scholar