Abstract
The formation of trihalomethane precursor from Microcystis aeruginosa was investigated by the culture in the laboratory. Culture medium was taken periodically during the growth period. Both filtrate and residue which were separated by filtration of the culture medium were chlorinated and the concentration of trihalomethane produced was measured by head space method.
Amounts of trihalomethane produced from the filtrate are much more than those from the residue after the stationary growth phase of Microcystis aeruginosa. And the trihalomethane formation potential reaches to 32.7 (THMp g / TOC mg).
Besides, by gel chromatography using Sephadex G-25, organics in the filtrate are fractionated into three components. The second fractionated component which molecular weight is about 2, 000-3, 000 showed the highest trihalomethane formation potential. It is concluded that this component is different from the extracelluar matrix of Microcystis aeruginosa judging from the results of gel chromatography and trihalomethane formation potential.

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Measuring method of phytoplankton ATP was experimentally investigated using a suspension of Scenedesmus dimorphus. Boiling glycine buffer including Mg-EDTA (O.O1M and 0.005M respectively, and pH 10.0) was found to be more suitable as an ATP extractant and also as a buffer solution to prepare ATP standard solution than boiling Tris buffer (0.025M, pH 7.75). ATP was stable in glycine buffer inculding Mg-EDTA for sixty-eight days at any selected storage temperature, whereas ATP was hydrolyzed in Tris buffer to some extent depending upon storage temperature and storage period. The optimum condition for ATP extraction from phytoplankton using glycine buffer including Mg-EDTA was identified as follows; heating system: test tube-block heater, extraction temperature (block heater temperature): 120°C, and extraction period: one minute. The results of the application study of the method proposed above are also described.

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The heavy metals pollution sources of sediments in Ohtake Coastal area have been studied using sediment cores, where industrialization begins after 1935 yr and chemical fiber, pulp and petroleum chemical factories are located today.
The elements of high concentrations in sediments were correlated with using chemicals contained themselves or contaminated from them in factories. The vertical and horizontal profiles of the heavy metals concentrations were reflected the stages of industrialization of the sampling site.
Mercury concentration in 0-5 cm was lower than in 50-55 cm layer at the factory near site. This phenomenon was different from other element. It may be the result by markedly decreasing of Hg contained in caustic soda as impurity since 1967.
A petroleum chemical factory had used Mn, but the concentration did not increased. As Mn solubility increase in reductive conditions and this investigation area was reported to polluted by organic matters, Mn in sediments assumed to transfer into water layer for the formation of Mn2+ ions.

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Abstract
At present in Japan industrial wastes are disposed in accordance with Waste Disposal and Public Cleansing Law.
For sludge produced through waste treatment process it is tested by the stipulated method to detect any hazardous substances in it, and the sludge judged to contain such substances must be disposed in a mandatory way. But in reality most of wastes are judged not to contain hazardous substances and are disposed by an ordinary reclamation method. There is no denying the possibility, however, that wastes thus disposed will threaten to pollute the environment in the future.
In this view the authors conducted several heavy metals extraction test of wastes treatment sludge. The results showed that, some of heavy metals was extracted in the experiment using the drainage taken from Inside-Central-Breakwater Waste Disposal Site, although very little of them was extracted by the stipulated method.
These findings seem to suggest that a large amount of sludge which is now being disposed ordinarily be disposed in an isolation reclamation way, and that the stipulated Criteria to judge “hazardous” be made as severe as the Effluent Standard Levels.

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Wastewater treatment plant of our laboratories consists of a neutralization tank and a plain sedimentation tank. Active growth of algae, especially a few species of Euglena and Chlorella, was observed in the sedimentation tank in spite of average detention time of 20 hrs. Freshly deposited sediments which mainly consists of algae were estimated to be 5-10g/m² day. Chlorella sp. isolated from the sedimentation tank grew in a glycine and a glucose medium and specific growth rates (μ) of 3.35 and 2.70 day^-1 were obtaind.
Although only a little growth was observed in a pepton medium, the isolate could grow pormptly in the medium under the co-existence of some bacteria isolated from the tank. This result indicates that symbiotical growth of algae and bacteria may take place in the actual sedimentation tank.
Algal growth in the tank favoured the reduction of BOD and trace amounts of metal ions in wastewater. Freshly deposited sediments contained considerable amounts of metals (e.g. Hg⁺⁺30-100 mg /kg, Cu⁺⁺ 2400-2700 mg/kg, Pb⁺⁺2500-10700 mg/kg), whereas wastewater contained 0.1-8.0μg/1, 0.02-0.35 mg/l, and 0.01-3.6 mg/l, respectively. Heavy metals in the sediments were stable under anaerobic condition and no release of metal ion to the aqueous phase was observed for 7 months period. No release nor volatilization of mercury from the sediments was also obsered under anaerobic and aerobic conditions.

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Required conditions for the wastewater treatment through soil are quantitatively discussed from the kinetic point of view. In order to have satisfactory treatment of wastewater by soil both BOD and hydraulic loadings per unit effective volume of soil and per unit area of land utilized will have to be sufficiently large in order compared with conventional mechanized treatment processes. Under such low loadings; the residence time of wastewater within the effective volume of soil can be kept so long that the BOD can be removed by soil bacteria under their endogenous respiratory conditions. This will avoid the plugging of void in soil by the excess growth of the bacteria, The void fraction of soil will be an important factor which controls the transfer of oxygen consumed by bacterial activity.

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