Water Treatment Systems and Technology for the Removal of Odor Compounds

Abstract

Compounds responsible for a musty odor in Lake Biwa have been detected at Isoshima Point in the Yodo river, the intake point of the Murano Purification Plant of Osaka Prefectural Government. 2-Methylisoborneol (MIB) and geosmin have been measured at maximum concentrations in raw water of 103 ng/l and 362 ng/l, respectively (1983–1986). The rapid sand filtration system normally in use has a low efficiency for the removal of such odor compounds, so a study of the following removal technologies: powdered and granular activated carbon (PAC,GAC), ozone and bio-film, was undertaken. The most effective was GAC treatment (linear velocity: 10–22 m/hr, space velocity: 7–16/hr) which completely removed the musty odor compounds. However, when the removal rate of total organic carbon by the GAC system decreased below 30%, the system's ability to remove the odor from the water also decreased.