Reduction Test of Hydrogen Sulfide in the Silty Sediment of the Fukuyama Inner Harbor Using Steelmaking Slag

Abstract

Environmental conditions suitable for growth of sulfate-reducing bacteria are provided by oxygen depletion due to decomposition of organic matter, and as a result, hydrogen sulfide is generated in enclosed coastal seas. It is highly toxic, depletes oxygen and generates blue tide. The purpose of this study is to evaluate the effects of removal of the sulfide in silty sediments by steelmaking slag. The silty sediments were collected in Fukuyama inner harbor located in the back of the bay part of Fukuyama Port, where odor trouble had caused by hydrogen sulfide generation. The steelmaking slag was placed on or mixed with the sediments in plastic containers with tight caps, and the water, sediment and hydrogen sulfide gas were monitored in a laboratory. The results showed that steelmaking slag reduced the dissolved sulfide in both the overlying water and the interstitial water in the sediment as well as the concentration of hydrogen sulfide gas. The analysis of SEM-EDX was suggested that iron sulfide was created on the slag surface immersed in the silty sediment. The results imply that applying steelmaking slag can effectively improve the water and sediment quality of coastal areas by capping on or mixing with the sediments.