Behavior and Countermeasures of Musty Odor Producing Cyanobacteria on the Riverbed～A study on upstream of Tama river～

Abstract

Recently Tama river, the water source of Tokyo, has a problem with 2-MIB caused by Phormidium autumnale. In August 2013, 220ng/L of 2-MIB was detected from raw water of the purification plant. In high water temperature period in summer, 2-MIB concentration was very high although there were a small amount of cyanobacteria. In contrast, in low temperature period in winter, 2-MIB concentration wasn’t so high although there were a large amount of cyanobacteria. From these results, it is suggested that production and release of 2-MIB of cyanobacteria was affected by water temperature. Based on the result of a hydraulic experiment model, we introduced intermediate chlorination to take measures against high concentration 2-MIB. As a result, the removal capacity of 2-MIB was doubled.