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Inorganic copper compounds are not considered as synthetic fertilizers for apple trees as they are traditional fertilizers. Thus, they are used in organic farming for soil or foliar applications. The European Union is for health reasons interested in reducing copper in apple orchards. Because the fertilizer application rate affects the nutrition of apples, the applied copper might also be reflected in the copper concentration of apple juices. Thus, the determination of copper is of concern for investigating the application of copper-containing fertilizers. Samples of clarified apple juice commercially available in the European market were analyzed for their copper content. Prior to quantification by inductively coupled plasma-optical emission spectrometry, the juices were processed by a microwave-assisted digestion system using HNO(3). All samples were also measured directly after dilution with HNO(3). The copper concentrations measured using both methods were all below the limit of detection (17 microg/L).

Abstract. Biomass incineration is increasingly used for the generation of heat and/or electricity. After incineration two ash fractions remain. Bottom ashes (the coarser ash fraction) can usually be used as fertilizing agent on fields as it contains valuable elements for soils and plants and only minor concentrations of heavy metals. Fly ashes (the finer ash fraction) are in most cases disposed as their heavy metal concentrations are too high for a usage as soil enhancer. In this study highly heavy metal contaminated fly ash has been cleaned through extraction with hydrochloric acid. The heavy metals were removed from the extract by precipitation with sodium hydroxide. After the cleaning procedure the ash can be pelletized and be returned to the soils.

In this paper a two stage bench scale leaching procedure is used to assess the heavy metals release from a wood-based fly ash of a 5.0 MWth grate-fired boiler. In the first step mostly K was leached with water. In the subsequent acid leaching step heavy metals were leached at a pH of 3. The remaining solids were agglomerated together with the bottom ash and the dried K-concentrate from the first leaching step whereas the filtrate was treated before discharge. In the agglomerates produced the heavy metal concentrations were below the limit concentrations for utilization. The loss of nutrients caused by the treatment was about 10% for Ca and for K 8%. The addition of 15% hydrated lime in the agglomeration step showed a very positive effect on the reduction of the fines contained in the product and on the mechanical stability of the agglomerates. The mass of the precipitate from the waste water treatment was about 10% of the mass of the fly ash. Thus, the mass of residue requiring disposal in landfill sites was reduced substantially. The heavy metal concentrations in the treated discharge water were significantly lower than typical limit values for waste water. This paper also presents the current heavy metal limit values for ash used as a soil conditioner in forestry and agriculture in Austria,