Design and operational strategies for the coal gasification wastewater treatment with the fluidized-bed granular activated carbon (GAC) anaerobic reactor were discussed with the mathematical model presented. Equations which show the relationships at steady state between treatment performance and operational parameters, such as specific GAC replacement rate, GAC medium mass per reactor volume, superficial hydraulic retention time, influent COD loading, and strength of the wastewater. Critical and optimum growth conditions of the bacteria degrading inhibitory organics were also discussed and operational range of specific GAC replacement rate was determined for supporting the bacterial growth. Stability of the process against the step-increase and step-decrease in the wastewater strength was also discussed with x_A-x_H relation figure and trajectories on the x_A-x_H phase plane.

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In the downstream of the Tamagawa river, the process of biodegradation of petroleum hydrocarbons was investigated.
Petroleum hydocarbons such as hexadecane, octylbenzene and 1-methylnaphtalene were rapidly degraded by microorganisms in the water sampled from the surface of the river after a period of lag time. The longer lag time was observed in order of hexadecane<octylbenzene<1-methylnaphtalene and was not shortened by physical and chemical emulsification. However, after the microorganisms were acclimated by these hydrocarbons, they were degraded without the lag time and the the rates could not be enhanced by physical and chemical emulsification. It seem that petroleum hydrocarbons were degraded not in physical and chemical process that the hydrocarbons were emulsified by microbial extracellular products, microfinded and enhanced contact area or frequency to microbes, but in biochemical process that the microorganisms gained the ability of petroleum hydrocarbons degradation, that is, induction of production of a degrading enzyme.
In the case where petroleum hydrocarbons is accidentally spilled out, they seemed likely not to be degrade immediately, but with the acclimation, they can be degraded rapidly.

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The methylation method with dazomethane is often used for the derivatization of the constituents of humic materials but it has some problems. We used three methylation methods, Diazomethane, Phase-Transfer-Catalyzed and Dimethyl Sulfate-Potassium Carbonate methylation to obtain reaction ratios for 22 kinds of aromatic model compounds. These compounds had hydroxy and carboxy substituents. The Dimethyl Sulfate-Potassium Carbonate methylation method was found to be best.
KMn04 degradation products of humic acid were also methylated by the three methods. As in the case of the model compounds, Dimethyl Sulfate-Potassium Carbonate methylation was found Best. The decomposition compounds in most cases were benzene polycarboxylic acids.

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The removal of phenolic compounds by using peroxidase of pak-bung (Ipomoea aquatica) was studied for an effective utilization of pak-bung which can be harvested in great quantities as the by-product of channel flow type wastewater treatment process. Peroxidase activities of pak-bung in leaf, stem and root portions were revealed to be 26.9, 28.1 and 44.6 U·g^-1 wet weight, respectively. Crude peroxidase extract could be easily prepared by homogenizing pak-bung tissue with tap water. Peroxidase activity of this crude extract could be maintained with only 10% reduction of its activity at storage temperature of -80°C. Optimum treatment condition for phenol solution of 100mg·l^-1 was experimentally determined to be as follows; initial pH =5.0, initial H₂O₂ concentration 2.5mM, initial peroxidase activity 0.3U·ml^-1 and reaction time 5 hours. Phenol removal efficiency became higher through divided addition of H₂O₂, owing to less inactivation of Peroxidase by H₂O₂. Peroxidase crude extract could also remove 1-naphthol and 8-hydroxyquinoline at removal efficiency over 95%. Moreover, peroxidase crude extract was shown to remove phenol in diluted industrial phenolic wastewater (ca. 1, 000 mg-phenol·l^-1) at about 85%.

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