抄録
This paper describes a pilot plant study on algae removal of a fluidized bed biofilm reactor system for lake water treatment. The system does not need backwashing because the fluidized bed suffers no clogging. Moreover, the system uses dissolved oxygen in influent water for aerobic biological treatment without aeration equipment. Thus, this system is a low energy and easy maintenance way to purify eutrophic lake water. The system was operated continuously at a flow rate of 1500 m3·d-1 for 9 months at Tsuchiura Port in Lake Kasumigaura. In this study, chlorophyll-a and dissolved oxygen in both influent and effluent water were monitored continuously. In summer (August to September) when water bloom occurred, the average removal efficiency of chlorophyll-a was 64% at the average influent chlorophyll-a concentration of 137.8 μg·l-1. During the total experimental period (9 months), the average daily amount of removed chlorophyll-a was 40.3g·d-1 at the average influent chlorophyll-a concentration of 89.5 μg·l-1. By analyzing the relationship between the removed chlorophyll-a and the consumption of dissolved oxygen, it was estimated that almost all of algae trapped in the reactor was degraded biologically.
