Volatile chlorinated substances produced by chlorination of humic acid were identified, and possible formation mechanism of one of these substances, chloropicrin, was investigated.
The results obtained were as follows.
(1) Volatile chlorinated substances were identified chloropicrin and carbon tetrachloride besides chloroform by GC-MS with a computarized data system.
(2) Precursors for the chloropicrin formation were amino acids such as alanine, threonine, ornithine, gultamic acid and glycine; nitro- or nitrosophenols; nitro- or nitrosoresorcinols; nitromethane and nitro- ethane.
(3) Chloropicrin was produced by chlorination of humic acid and resorcinol in the presence of nitrite.
(4) Mechanism of chloropicrin formation by chlorination of alanine was proposed as follows : Alanine was decarboxylated (-COOH→CO₂↑), oxidized (-NH₂→-NO2) and consequently chlorinated to chloropicrin.
(5) As for mechanism of chloropicrin formation by chlorination of resorcinol in the presence of nitrite, it was recognized that nitrososubstitution of resorcinol occurred in the presence of nitrite and produces nitrosoresorcinol, which was oxidized to nitroresorcinol with hypochlorite, and finally nitroresorcinol formed chloropicrin by the way of the ROOK's reaction of chloroform formation from resorcinol.

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Influent load of oil (hexan-extractable materials) and mechanism of it's removal in municipal sewage treatment plants recieving domestic wastewater mainly were investigated.
Oil discharge per capita from household was about 7g/d, and was considered to be derived from fecal materials and housework (vegetable and animal oil). In combined sewerage systems, however, it was found that larger amounts of oil which had been settled in sewers were washed out by rainstorm.
Oil removal was performed more than 95% in conventional activated sludge process, and the following two stages were attributed; (1) Sedimentation of settleable oil in primary settling tank, (2) Rapid adsorption and relatively slow biochemical decomposition by activated sludge, and sedimentation in final settling tank.

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The reductive dissolution of Mn (III) or Mn (IV) oxides with ferrous ion, which is produced by oxidation of iron sulfides, such as pyrite, is considered as a a cause of dissolution of manganese ion into mine waters. The dissolution of manganite and pyrolusite with ferrous ion has been investigated from this point of view. In this experiment, pH of solution was kept at constant values by using a pH stat.
The reaction of manganite and pyrolusite with ferrous ion in sulfuric acid solution were supposed to be expressed as :
2MnOOH+2FeSO₄+3H₂SO₄=2MnSO₄+Fe₂ (SO₄) 3+4H₂O (pH<3)
2MnOOH+2FeSO₄+2H₂O=2MnSO₄+2Fe (OH) ₃ (pH>3)
MnO₂+2FeSO₄+2H₂SO₄=MnSO₄+Fe₂ (SO₄) ₃+2H₂O (pH<3)
and
MnO₂+2FeSO₄+4H₂O=MnSO₄+2Fe (OH) 3+H₂SO₄ (pH>3)
The dependencies of hydrogen ion concentration on the dissolution rates of manganite were 0.5th order below pH 3. On the other hand, the dissolution rates of pyrolusite were 2nd order with respects to hydrogen ion concentration at pH 2 to 3 and constant below pH 2. Also, the dissolution rates of pyrolusite were considerably higher than those of manganite below pH 3, but, the former were lower than the latter above pH 3.
The dependencies of ferrous ion concentration on the dissolution rates were 0.5th order for manganite and 1st order for pyrolusite.
The activation energies for the reductive dissolution were 15.2 kcal/mole for manganite and 4.9 kcal/mole for pyrolusite. From these values for activation energies, the overall reactions were supposed to be controlled by chemical reaction for manganite and by diffusion process for pyrolusite.

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Adsorption rates and capacities of ten kinds of anionic, cationic and nonionic surfactants on various clay minerals such as kaolinite, Korean kaoline, montmorillonite, bentonites and sepiolite were investigated.
The adsorption rates of all the surfactants on the clay minerals were rapid, and the equilibriums were attained within about thirty minutes. The adsorption isotherms of these surfactants for the clay minerals were conformed to the Freundlich equation. The adsorption capacities of these surfactants on the clay minerals were large in the following order; cationic surfactants> nonionic surfactants> anionic surfactants.
Montmorillonite and bentonites, which have large cation exchange capacities, adsorbed much amount of the cationic surfactants. Sepiolite, montmorillonite and bentonites, which have many micro-pores, adsorbed much amount of the nonionic surfactants. On the other hand, kaolinite and Korean kaoline, which have small cation exchange capacities, adsorbed more the anionic surfactants than the other clay minerals.
Concequently, it would be suggested that cationic and nonionic surfactants were much adsorbed and accumulated in suspended solids and sediments in the river, lake and sea. Furthermore, it would be possible to use the clay minerals for treatment of wastewater containing these surfactants.

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A bacterium which gives the high denitrifying activity at low temperature was isolated from rice field soil. Almost all the properties of the new isolate (N-1 strain) were in good agreement with those of Pseudomonas fluorescens.
For the dentirification by N-1 strain, optimum C/N ratio was about 3.5, and optimum temperature was about 25°C. Acetic acid, citric acid, and glycerin were good carbon sources for the dentirification by N-l strain.
The specific removal rate of N0^-₃-Nin the batch experiments at 5°C varied from 0.0140 to 0.0210 mg N0^-₃-N/mg Cell/hr.

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