|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1994 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1993 : ¥1,000,000 (Direct Cost : ¥1,000,000)
In order to investigate the relation ship between treatment efficiency and operation conditions, characteristics of attachment and desorption of biofilm, and the immobilization of microorganisms on the biological activated carbon. A series of pilot plants called the biological activated carbon fluidized bed process were installed, and the real polluted lake waters (SS=15mg/l, COD=8mg/l) were used in these pilot plant experiments. The result obtained through this experimental study may be summarized as follows.
The treatment efficiency for organic matter such as TOC and DOC was found to be increased if the hydraulic retention time (HRT) increased, while the HRT was increased from 0.5 to 2 hours. It was recognized that HRT=1 hour was more reasonable in this process, and the removal of TOC and DOC was more than 40%. In the meantime the removals of SS,ammonium nitrogen and algae were found to be 50%, 55% and 50%, respectively. Although the treatment efficiency decreased after some periods of operation, it can be recovered through the proper backwash by the combination of water and air every two weeks.
10 species of Flagellate, 17 Ciliata, 17 Sarcodina, ( Metazoa (including Rotatoria, Nematoda, Oligochaeta) were investigated in the fluidized bed process. The dominant species were found to be Monas, Vorticella, Epistylis, Stentor and Philodina, and the maximum population was 500/ml. Nematoda was found to be an obstruct organism, its control is still being studied. Pseudomonas, Alcaligenes, Acinetobacter etc. were lso recognized, the population reached to 10^7-10^8/ml.
It was verified that the treated water by this process could be used as a source of raw water for water supply.