Purification of Polluted Stream using Zeolite Tank laid Methanol Permeation Tube.

概要

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The new system for the purification of polluted river water was proposed and examined.The system is composed of zeolite as the soil material in the tank and a silicon rubber tube laid in zeolite as the supplying system of a hydrogen donor (methanol) for denitrification. First, it was cleared that the methanol permeation velocity could be controlled by the membrane thickness and the methanol concentration in a tube (CMe) . Then, the effects of the hydraulic retention time (HRT=φ·V/Q, φ: porosity) and CMe to the removal of nitrogen were investigated using a small-sized experimental apparatus at room temperature of 20°C. The nitrogen removal from artificial polluted river water of NO3-N=10mg/l was about 70% under the condition of HRT=2hr and CMe=20%. Although the removal efficiency of nitrogen reached above 90% in the case of HRT=2hr and CMe=25-50%, the nitrogen removal rate per unit tank volume was saturated at about 1.7g/m3/hr. The on-site purification experiment of actual river water was performed using a large-scale experimental tank (1×1×4.8 m) in winter season in 1997. As the results, it was confirmed that the NH4-N, NO3-N and T-N removals on the condition of HRT=2hr and CMe=25% were 100%, 64% and 69%, respectively, in spite of low water temperature below 10°C.
日本水処理生物学会の論文