Numerical Model Analyses on the Effects of Steelmaking Slag Addition to Growth of the Marine Diatom Skeletonema costatum: Importance of pH Effects

Abstract

Numerical model analyses were made on the experimental results in order to determine the optimum amount of dephosphorized steelmaking slag addition to enhance the growth of the planktonic diatom Skeletonema costatum. In the batch culture experiments, the growth of S. costatum was optimally enhanced by an addition of 100 mg L^-1 slag due to dissolution of phosphate and silicate from the slag. However, increase in pH due to the effect of calcium oxide, which is the major constituent of the slag, negatively affected on the growth. The model outputs explained the processes underlying the batch culture experiments. Further, the sensitivity analyses provided the appropriate amount of slag addition that should be applied to enhance the growth of marine diatom populations under the influence of pH increase.