Effect of decontaminated wood ash on soil fertility

AI Quick Summary

In Switzerland, large amount of wood ash is produced. Its disposal on landfills is costly and not sustainable. Wood ash is composed of nutrients that could be recycled as fertilizer. However, it can contain high trace metal element (TME) contents that prevent them from being used as fertilizer. Methods were developed to remove TME. This study will test the effect of decontaminated ash on soil fertility. Contaminated ash recycling would alleviate environmental footprint while upgrading a waste. In Switzerland, the ash is disposed of in landfill sites, generates a cost and could be problematic when the maximum storage capacity is reached. Also, all mineral fertilizers are imported. As the quantities of K contained in clean wood ash are significant on a national scale, and as ash fertilization confers various agronomic benefits, the recycling of ash as raw material for K fertilizer is currently investigated. The physical and chemical properties of ash vary significantly depending on many factors (i.e. geographical location and industrial processes). Wood ash is composed of many nutrients available for crops (e.g. K, Ca, Si, P and Mg). In addition, a wood ash fertilization increases microbial biomass and/or activity, soil N mineralization and soil pH which, in turn, can enhance crop production.Recycling wood ash as a fertilizer would allow the nutrient cycle to be completed by returning nutrients taken from the soil. Additionally, importation of K fertilizer would be at least partly avoided and a waste product would be economically revaluated.However, wood ash can have trace metal elements (TMEs) contents not environmentally acceptable. In fact, certain ashes are known to have high TMEs contents and have to be decontaminated for recycling as fertilizer. Extraction methods are available to remove the majority of TMEs from the ash. To our knowledge, the influence of decontaminated ash on soil fertility has never been explored. This will be tested in this study in order to point out the possibility of an upgrading of contaminated ash as raw material for K fertilizer production after treatment with water, nitric acid and whey milk (a byproduct from cheese making that it is not currently valorized). The results from this study could open up new recycling opportunities for contaminated ash and whey milk while providing a sustainable and profitable solution based on a circular economy concept. Finally, the use of ash as fertilizer would reduce if not eliminate the import of mineral K fertilizer (a fossil resource) from elsewhere reducing significantly carbon emissions.

Project Idea Metadata

• Project Idea Name: Effect of decontaminated wood ash on soil fertility
• Date: 3/3/2023 12:01:49 AM
• Administrators:
  • Mario Fontana

Project Idea Description

In Switzerland, the ash is disposed of in landfill sites, generates a cost and could be problematic when the maximum storage capacity is reached. Also, all mineral fertilizers are imported. As the quantities of K contained in clean wood ash are significant on a national scale, and as ash fertilization confers various agronomic benefits, the recycling of ash as raw material for K fertilizer is currently investigated. The physical and chemical properties of ash vary significantly depending on many factors (i.e. geographical location and industrial processes). Wood ash is composed of many nutrients available for crops (e.g. K, Ca, Si, P and Mg). In addition, a wood ash fertilization increases microbial biomass and/or activity, soil N mineralization and soil pH which, in turn, can enhance crop production.

Recycling wood ash as a fertilizer would allow the nutrient cycle to be completed by returning nutrients taken from the soil. Additionally, importation of K fertilizer would be at least partly avoided and a waste product would be economically revaluated.

However, wood ash can have trace metal elements (TMEs) contents not environmentally acceptable. In fact, certain ashes are known to have high TMEs contents and have to be decontaminated for recycling as fertilizer. Extraction methods are available to remove the majority of TMEs from the ash. To our knowledge, the influence of decontaminated ash on soil fertility has never been explored. This will be tested in this study in order to point out the possibility of an upgrading of contaminated ash as raw material for K fertilizer production after treatment with water, nitric acid and whey milk (a byproduct from cheese making that it is not currently valorized). The results from this study could open up new recycling opportunities for contaminated ash and whey milk while providing a sustainable and profitable solution based on a circular economy concept. Finally, the use of ash as fertilizer would reduce if not eliminate the import of mineral K fertilizer (a fossil resource) from elsewhere reducing significantly carbon emissions.

In Switzerland, large amount of wood ash is produced. Its disposal on landfills is costly and not sustainable. Wood ash is composed of nutrients that could be recycled as fertilizer. However, it can contain high trace metal element (TME) contents that prevent them from being used as fertilizer. Methods were developed to remove TME. This study will test the effect of decontaminated ash on soil fertility. Contaminated ash recycling would alleviate environmental footprint while upgrading a waste.