QUANTITATIVE ANALYSIS OF ARTIFICIAL REEF FOR WATER-PURIFY WHICH USES THE SHELL INSTALLED IN HARBOR

Abstract

 A harbor water area is calm and precious place to various aquatic lives, but its closure environment often makes water and deposit worse. As one of the measures those aggravation, artificial reefs for waterpurification which uses a shell have been installed in Tsuruga harbor in Fukui pref. In order to quantitatively evaluate the water purification effect of those reefs, we pulled up the test piece through the four seasons, and examined a temporal change by addition to diatoms in the tanks. As a result, the water purification effect was demonstrated by immediate decreasing the amounts of diatoms and organic carbon, and increasing the clarity of the water visually. Although the effect was decreased in low-temperature season, the water purification effect was confirmed through all seasons. Moreover, when those results experimentally calculated to economic effects, with sewage disposal expense, it was corresponded in 4,550,000 yen per year by 16 reefs.