In order to makes clear the ability of treatment and the retaining characteristics of the anaerobic bacteria in the reactor, experiments were conducted employing four packing methods of the filter media in laboratory-scale anaerobic filters using synthetic sewage. The accumulation of high concentrations of biological solids in the anaerobic filter permits COD removal efficiency of 70 85%. There was no significant difference of treatment efficiency among the four methods, but the numbers of bacteria and their activities were really different from each other in the reactors. The investigation on the characteristic of bacterial distribution showed that the number of bacteria at tacked on the filter media was the largest in all of the reactors, these attached bacteria had greater treatment ability than that of the bacteria sedimenting and accumulating on the bottom of the reactors when hydoraulic retention time was shorter than 6 hours. The numbers of the acidogenic bacteria and methanogenic bacteria attached to the filter media were respectively 10¹⁰ cells 10⁹ cells in the reactors.

View full abstract

There Polycyclic aromatic hydrocarbons (PAH : Benzo (a) Pyrene (BaP), Benzo (k) Fluoranthene (BkF), Benzo (b) Fluoranthene (BbF)) in 23 surface sediments and 2 core sediments from The Sea of Suo have been analyzed by HPLC with fluorescence detection. BaP concentrations in the surface sediments ranges from 10.4 to 338 ng · g^-1-dry sediment. PAH concentrations in the eastern area of the sea are lower than these in the central and western area of the sea.
The increase in PAH toward the surface from 45cm depth at St. 23 and from 30cm depth at St. 1 were approximately exponential and PAH concentrations under those depth were constant. The age of 45cm depth at St. 23 corresponds to about 1920 by ²¹⁰Pb-chronology.
Distance indices were calculated to examine the similarity among samples in terms of the relative abundance of individual PAH. Samples except for St. 15 were classified into 2 groups (Group I, II and Group III, IV) by distance indices.
These results suggested that the PAH input in areas of GroupI, II and III, IV were different.

View full abstract

Effects of phenol concentration in the reactor, i.e. phenolic stress, on the biodegradation potential of activated sludge was studied during the process of the acclimation of activated sludge to phenolic wastewater. Three types of reactor operations, i.e. continuous flow operation, aerobic sequencing batch operation, and anaerobic/aerobic sequencing batch operation, and two loading procedure, i.e. elevating load and constant load, were taken into consideration.
Phenol degrading activity of activated sludge acclimated by aerobic batch operation with constant load was the highest. It was suggested that batch operation was effective to select phenol degrading bacteria and moderately high phenolic stress was effective for increasing the biodegradation potential of activated sludge.
Phenol degrading activity of acclimated activated sludge decreased under continuous flow operation and low sludge loading operation of sequencing batch operation. It was suggested that moderately high phenolic stress and moderately high sludge load for sequencing batch operation was preferable for keeping the biodegradation potential of acclimated activated sludge.

View full abstract

[in Japanese]

View full abstract