Dissolution Characteristics of Ammonium and Nitrate in Soil with Bottom Ash from Biomass Power Plant

Abstract

Recently, biomass power plants are increasing as an alternative energy source to reduce the carbon emissions from fossil fuels. The amount of waste from biomass power plants increases and bottom ash is generally buried in soil. However, there is little research on the dissolution characteristics of nitrogen, a macronutrient in soil, using bottom ash (BA). To evaluate nitrogen dissolution in soil with BA, we mixed BA with soil, collected leachate for 5 weeks, and measured NH4+-N and NO3--N concentration in leachate. As a results, BA reduced the leaching of NH4+-N and NO3--N by up to 18% and 38%, respectively. The decrease of NH4+-N leaching is judged to be the result of increased NH4+-N adsorption due to the high pH of the bottom ash, and these results are often confirmed in other biochar. The NO3--N leaching also decreased, but it is not related to the adsorption capacity of BA, so further research is needed. These results suggested that BA reduces the contents of NH4+-N and NO3--N in the soil effluent, which can be used as an important indicator for using bottom ash in the soil.The amount of NH4+-N and NO3--N dissolution in soil using bottom ash from biomass power plant (average and standard deviation; 3 replicate). (left) Accumulation of NH4+-N; (right) Accumulation of NO3--N.