THESIS
2016
xvi, 74 pages : illustrations ; 30 cm
Abstract
Municipal solid waste (MSW) landfill is a major source of odorous gases, such as hydrogen
sulfide (H
2S). To remove H
2S, 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 H
2S removal process in GGBS amended soil. Loess soil was amended with 0%, 10%, or 30% GGBS, compacted to
a bulk density (1.54 g/cm
3) in a column, and then applied with a concentration of 1000 ppm H
2S 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 H
2S could be reduced to below the olfactory threshold (0.02 ppm). H
2S breakthrough took...[
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Municipal solid waste (MSW) landfill is a major source of odorous gases, such as hydrogen
sulfide (H
2S). To remove H
2S, 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 H
2S removal process in GGBS amended soil. Loess soil was amended with 0%, 10%, or 30% GGBS, compacted to
a bulk density (1.54 g/cm
3) in a column, and then applied with a concentration of 1000 ppm H
2S 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 H
2S could be reduced to below the olfactory threshold (0.02 ppm). H
2S 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 H
2S and GGBS amended soil was combined process of oxidation and
acid-base reaction. The principal mechanism to remove H
2S 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 H
2S 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 H
2S efficiently and can be regenerated several times makes GGBS a cost-effective and environmentally friendly soil conditioner for reducing H
2S concentration.
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