The contents of organic halogenated compounds in nonvolatile hexane-soluble neutral organic materials of supplied water were characterized by means of GC-MS, GC-ECD, and TOX.
The following conclusions were drawn from analysis of the date collected.
1) A number of organic halogenated compounds had greater polarity.
2) A number of organic halogenated compounds identified by GC-MS were organochlorine herbicides and insecticide.
3) TCTP, oxadiazon, CNP and chlomethoxynil were detected at the level of ppt during the months they were used. However, α-BHC was detected to the order of ppt throughout the year.
4) The amounts used of TCTP and oxadiazon were respectively less than CNP. But the concentration of TCTP and oxadiazon in supplied water were greater than CNP.
5) The organochlorine herbicides and insecticide of extreme low concentration were usually not removed at water purification plants.
6) The organic halogenated compounds except organochlorine herbicides and insecticide existed markedly in supplied water.

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Anaerobic reaction in addition to aerobic reaction were introduced into a biological treatment process for wastewater containing toxic chemicals such as phenol, thiocyanate and ammonium sulfate to study the performance of anaerobic reaction. Four experimental systems, i. e. continuous flow activated sludge prosess, continuous flow submerged filter (honeycomb tube) prosess, sequencing batch reactor activated sludge prosess and sequencing batch submerged filter prosess were compared.
TOC, phenol and thiocyanate were efficiently removed by all the systems, and particularly in the anaerobic process. Although denitrifying bacteria were noted in the sludge, little ammonium nitrogen could be removed by the washout of the nitrifying bacteria. Thiocyanate concentration up until 300 mg·l^-1 showed no inhibition on the biodegradation of phenol.
Both the continuous flow reactors and the sequencing batch reactors discharged effluents with low TOC, the activated sludge process showed better performance for TOC removal than the submerged filter process.

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Galvanostatic electrolysis of CHCl₃ in aqueous solution on various metal cathodes was studied. The concentration of CHCl₃ in aqueous solution decreased upon electrolysis and the main products were CH₄, CH₂Cl₂ and H₂. Formation of CH₃Cl was negligible. Cu and Ni cathodes yielded both CH₄ and CH₂Cl₂, while Pb cathode formed CH₂Cl₂ predominantly. The other metal cathodes mainly produced H₂ along with a small amount of CH₂Cl₂. In these electrolysis, an inverse relation between the yields of organic reduction product and H₂ was obtained, independent of the amount of electric charge.
Metal cathodes such as Cu and Pb, which have relatively large H₂ overpotential, resulted in higher yield of organic reduction product. In the galvanostatic electrolysis of CH₂Cl₂ the formation of CH₄ was negligible.
Electrolysis of lower concentration (0.8-0.6mg·l^-1) of CHCl₃ on Cu cathode gave CH₄ as the main product. Similar result was obtained with running water as a solvent.

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A fish image automonitoring system for detecting acute toxicity in water purification plants was studied experimentally. A stable image taking technique for fish was developed based on a lighting method, in which a translucent backscreen behind the water tank was illuminated and then scattered by the illumination lamp. An effective fish image recognition method, regardless to the degree of turbidity, was found, which was based on the histogram of the gray image.
The image automonitoring technique, in which both the location profile and the velocity profile of a fish swimming in the water tank was applied to evaluation of fish movement patterns. The normal movement patterns of carp (Cyprinus carpio), crucian carp (Carassius carassius buergeri), and broadstriped biteling (Rhodeus osellatus osellatus) differed from those under toxic conditions (cyanide ion= 0.1 mg·l^-1). Then toxicity could be detected on the basis of differences in fish movement patterns as determined by the image automonitoring system.

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[in Japanese]

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