DIRECT TREATMENT OF POLLUTED RIVER WATER BY THE MULTI-SOIL-LAYERING METHOD

概要

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Six Multi-Soil-Layering systems with combinations of two type of soils, Andisol (volcanic ash soil) and Entisol (granitic sandy soil), two particle size classes of zeolite, 1-3 and 3-5mm in diameter, and various hydraulic loading rates, 1 to 4 m3 m-2 day-1, were constructed and were compared for polluted river water treatment. Removal rates of BOD, T-N and T-P were 72.2 to 83.5 %, 22.4 to 50.5 %, and 51.9 to 66.8 %, respectively. Entisol was more efficient for T-N and T-P removal than Andisol. Zeolite of 1-3mm in diameter was more efficient for removal of all the pollutants than that of 3-5mm. These materials might contribute more effective contact of inlet water to the various components for purification in the MSL systems. Lower loading rate was more efficient for BOD and T-N removal. The loading rate of 2 m3 m-2 day-1 was the most efficient for T-P removal. However, differences in removal rates of these pollutants of river water among the MSL systems were small considering with the differences of hydraulic loading rates. The difference in BOD removal rates between MSL 1 and 6 was only 10 % against to 400 % difference in the loading rates between them. Although clogging was observed at the loading rate of 4 m3 m-2 day-1, the system was recovered after 2 months rest. These results indicated that higher loading rate, 4 m3 m-2 day-1, was more advantageous and practical for direct river water treatment.
Japan Society on Water Environmentの論文