Abstract
Three sediment treatments, the dissolved air flotation method (DAF), the MgO spread method and the combined method (hybrid method) to restrain the elution of nutrient salts were practiced for the control of the TN/TP ratio of lake water. The results were as follows; the hybrid method raised the TN/TP ratio with the advantageous effects of both DAF (restraint of nitrogen) and MgO spread methods (restraint of phosphorus). A significant decrease of the chlorophyll a concentration was observed using the hybrid method with a MgO dosage of more than 400 g/m2. The relationship between the TN/TP ratio and the chlorophyll a concentration in this study were consistent with the TN/TP ratio-chlorophyll a model represented by another study, so that, it could be summarized that the series of experiments regarding sediment treatments were quite reasonable (accurate). Therefore, each sediment treatment can be considered as a method to combat lake eutrophication from the view point of the TN/TP ratio.
