Landfill disposal is the only reasonable option for cyclone ash due to its elevated concentrations of the heavy metals Cd (25 mg kg–1; d.w.), Zn (3630 mg kg–1; d.w.), Ba (4260 mg kg–1; d.w.), and Hg (1.7 mg kg–1; d.w.). The distribution of heavy metals (i.e. Cd, Cu, Pb, Cr, Zn, As, V, and Ba) after a three-stage BCR sequential extraction procedure between the exchangeable (CH3COOH), easily reduced (NH2OH–HCl), and oxidizable (H2O2 + CH3COONH4) fractions showed that the highest concentrations of most of the heavy metals occurred in the oxidizable fraction. This indicates that a major part of the heavy metals retained in the cyclone ash originating from a small-scale (6 MW) municipal district heating plant incinerating forest residues (i.e. wood waste and bark) are not easily liberated under the conditions normally found in nature.
1. Ecke, H., Sakanakura, H., Matsuto, T., Tanaka, N. and Lagerkvist, A. State of the art treatment for municipal solid waste incineration residues in Japan. Waste Manage. Res., 2000, 18, 41–51.
doi:10.1034/j.1399-3070.2000.00097.x
2. Murakawa, T. Technology of a new type of treatment system used simultaneously on flue gas and its dust. Fuel Energy Abstr., 1998, 39, 64.
doi:10.1016/S0140-6701(97)86042-0
3. Ecke, H., Menad, N. and Lagerkvist, A. Treatment-oriented characterization of dry scrubber residue from municipal solid waste incineration. J. Mater. Cycles Waste Manage., 2002, 4, 117–126.
4. Filgueiras, A., Lavilla, I. and Bendicho, C. Chemical sequential extraction for metal partitioning in environmental solid samples. J. Environ. Monit., 2002, 4, 823–857.
doi:10.1039/b207574c
5. Kosson, D., van der Sloot, H., Sanchez, F. and Garrabrants, A. An integrated framework for evaluating leaching in waste management and utilization of secondary materials. Environ. Eng. Sci., 2002, 19, 159–204.
doi:10.1089/109287502760079188
6. Nurmesniemi, H., Pöykiö, R., Kuokkanen, T. and Rämö, J. Chemical sequential extraction of heavy metals and sulphur in bottom ash and in fly ash from a pulp and paper mill complex. Waste Manage. Res., 2007, 25, 1–12.
7. Dahl, O., Nurmesniemi, H. and Pöykiö, R. Sequential extraction partitioning of metals, sulfur, and phosphorus in bottom ash from a coal-fired power plant. Int. J. Environ. Anal. Chem., 2008, 88, 61–73.
doi:10.1080/03067310701461615
8. Nurmesniemi, H. and Pöykiö, R. Leachability of metals in grate-fired boiler wood ash from a small municipal district heating plant (6 MW). J. Res. Sci. Technol., 2006, 3, 217–225.
9. SFS-EN, 2000. The European standard SFS-EN 13037. Soil improvers and growing media. Determination of pH. Finnish Standards Association SFS. Finnish Environment Institute, Helsinki. 2000.
10. SFS-EN, 2000. The European standard SFS-EN 12880. Characterization of sludge. Determination of dry residue and water content. Finnish Standards Association SFS. Finnish Environment Institute, Helsinki. 2000.
11. SFS-EN, 2000. The European Standard SFS-EN 12879. Characterization of sludge. Determination of loss on ignition of dry mass. Finnish Standards Association SFS. Finnish Environment Institute, Helsinki. 2000.
12. SFS-EN, 2001. The European Standard SFS-EN 13137. Characterization of waste. Determination of total organic carbon (TOC) in waste, sludge and sediments. Finnish Standards Association SFS. General Industry Federation of Finland, Helsinki. 2001, 1–21.
13. USEPA Method 3051, 1992. Microwave assisted acid digestion of sediments, sludges, soils and oils. Washington DC, United States. Available from: http://www.epa.gov/SW-846/3052.pdf, accessed in November 2007.
14. Van Herck, P. and Vandecasteele, C. Evaluation of the use of a sequential extraction procedure for the characterization and treatment of metal containing solid waste. Waste Manage., 2001, 21, 685–694.
doi:10.1016/S0956-053X(01)00011-3
15. Adriano, D. and Weber, J. Influence of fly ash on soil physical properties and turfgrass establishment. J. Environ. Qual., 2001, 30, 596–601.
16. Pöykiö, R., Kuokkanen, T., Nurmesniemi, H. and Kujala, K. Extractability and bioavailability of heavy metals and sulfur in bottom ash and fly ash from an industrial power plant. J. Solid Waste Technol. Manage., 2007, 33, 171–182.
17. Earle, C., Rhue, D. and Earle, J. Mercury in a municipal solid waste landfill. Waste Manage. Res., 17, 305–312.
18. Das, A., Chakroborty, R., Ververa, M. and de la Guardia, M. Metal speciation in solid matrices. Talanta, 1995, 42, 1007–1030.
doi:10.1016/0039-9140(95)01557-R
19. Pöykiö, R., Nurmesniemi, H. and Keiski, R. L. Environmental risk assessment of heavy metal extractability in a biosludge from the biological wastewater treatment plant of a pulp and paper mill. Environ. Monit. Assess., 2007, 128, 153–164.
doi:10.1007/s10661-006-9301-y
20. Pöykiö, R., Nurmesniemi, H., Perämäki, P., Kuokkanen, T. and Välimäki, I. Leachability of metals in fly ash from a pulp and paper mill complex and environmental risk characterisation for eco-efficient utilization of fly ash as a fertilizer. Chem. Speciation Bioavailability, 2005, 1, 1–9.
21. Svensson, B. M., Mårtensson, L., Mathiasson, L. and Eskilsson, L. Leachability testing of metallic wastes. Waste Manage. Res., 2005, 23, 457–467.
doi:10.1177/0734242X05058684
22. Rauret, G. Extraction procedures for the determination of heavy metals in contaminated soil and sediment. Talanta, 1998, 46, 449–455.
doi:10.1016/S0039-9140(97)00406-2
23. Kazi, T. G., Jamali, M. K., Kazi, G. H., Arain, M. B., Afridi, H. I. and Siddiqui, A. Evaluating the mobility of toxic metals in untreated industrial wastewater sludge using a BCR sequential extraction procedure and a leaching test. Anal. Bioanal. Chem., 2005, 383, 297–304.
doi:10.1007/s00216-005-0004-y
24. Smichowski, P., Polla, G. and Gómez, D. Metal fractionation of atmospheric aerosols via sequential chemical extraction: a review. Anal. Bioanal. Chem., 2005, 381, 302–316.
doi:10.1007/s00216-004-2849-x
