MEASUREMENT OF DENITRIFICATION ACTIVITY OF THE BOTTOM SEDIMENT AT NOGAWA RIVER (Natural purification of an urban river ecosystem)

概要

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Nitrogen removal by denitrification in sediment and artificial substrate was measured at Nogawa River by continuous method, based on acetylene inhibition technique, during one year from December 1987 to November 1988. The quality of artificial substrate is an important factor for denitrification rate in a river bed sample. The denitrification rate per unit area in the river bed composed of concrete (13.8gN m⁻² year⁻¹) was higher than that in the gravel and sand (7.4gN m⁻² year⁻¹ ) river bed. The proportion of denitrificated nitrogen to the input nitrogen in the river was calculated. The average value for the concrete river bed was 0.3%, and 7.4% in the river bed of gravel and sand. From these results, if all area of Nogawa River was changed to a concrete bed, the proportion of denitrificatied nitrogen to input nitrogen is estimeted to be 1.7%, and about 3.1% in the case of a gravel and sand. Denitrification activity in the river bed of a small urban river was found to be dependent on the type of river bed.
信州大学理学部の論文