Municipal solid waste (MSW) landfill is a major source of odorous gases, such as hydrogen sulfide (H₂S). To remove H₂S, a novel technique was studied using ground granulated blast furnace slag (GGBS). Laboratory column tests, regeneration tests and chemical analysis were carried out to evaluate its effectiveness and to reveal the mechanisms of H₂S removal process in GGBS amended soil. Loess soil was amended with 0%, 10%, or 30% GGBS, compacted to a bulk density (1.54 g/cm³) in a column, and then applied with a concentration of 1000 ppm H₂S from the column bottom. Sulfur products formed on the surface of soil particle and in pore water were quantified. Test results showed that the concentration of H₂S could be reduced to below the olfactory threshold (0.02 ppm). H₂S breakthrough took...[ Read more ]

Municipal solid waste (MSW) landfill is a major source of odorous gases, such as hydrogen sulfide (H₂S). To remove H₂S, a novel technique was studied using ground granulated blast furnace slag (GGBS). Laboratory column tests, regeneration tests and chemical analysis were carried out to evaluate its effectiveness and to reveal the mechanisms of H₂S removal process in GGBS amended soil. Loess soil was amended with 0%, 10%, or 30% GGBS, compacted to a bulk density (1.54 g/cm³) in a column, and then applied with a concentration of 1000 ppm H₂S from the column bottom. Sulfur products formed on the surface of soil particle and in pore water were quantified. Test results showed that the concentration of H₂S could be reduced to below the olfactory threshold (0.02 ppm). H₂S breakthrough took three times the amount of time when soil with 30% GGBS was used instead of un-amended soil. Soil with 30% GGBS could achieve a removal capacity of 0.584 mg/g. After three cycles of regeneration enabled by air ventilation, the accumulated removal capacity was 1.44 mg/g. The test results also reveal that the reaction between H₂S and GGBS amended soil was combined process of oxidation and acid-base reaction. The principal mechanism to remove H₂S in GGBS amended soil was through the formation of acid volatile sulfide (AVS), elemental sulfur and thiosulfate. Soil pH value decreased gradually during regeneration and reuse cycles. It is found that the AVS plays a significant role in H₂S removal during regeneration and reuse cycles. Adding GGBS increased the production of AVS and at the same time suppressed the formation of elemental sulfur. This mechanism is found to be more prominent when the soil water content is higher, leading to increased removal capacity. The fact that GGBS amended soil can remove H₂S efficiently and can be regenerated several times makes GGBS a cost-effective and environmentally friendly soil conditioner for reducing H₂S concentration.