Accelerated carbonation of municipal solid waste incineration bottom ash for CO2 sequestration

Abstract

Municipal solid waste is being produced in large quantities, in keeping with a dramatic population increase and the growth of industrialization. Most of this waste is sent to landfills in South Korea. However, current treatment methods including incineration and recycling is limited owing to insufficient landfill space and the generation of leachates and soil contamination. Generally, 250–300 kg of bottom ash and 30–50 kg of fly ash are generated from one ton of incinerated municipal solid waste. This study seeks to determine the degree of influence of several main factors, such as the optimum temperature, solid-to-water ratio and CO2 concentration, on the process of accelerated carbonation of the bottom ash. The results show that the carbonation rate was at its highest at a temperature of 20°C, a solid-to-liquid ratio of 0.2 and with 20% CO2. This implies that the CO2 gas emitted from incinerators can be used directly as part of an accelerated carbonation process of bottom ash, as the water content of raw bottom ash is 15∼25% and the CO2 concentration emitted from incinerators is 5∼20%. However, the temperature should remain at less than 20°C for more effective carbonation.