QUANTITATIVE ANALYSIS OF CLEAN-UP-ABILITY WITH BIO-PRODUCT SUBSTRATA INSTALLED IN HARVOR

Abstract

  For quantitative assessment of water purifying ability in culture substrata that made use of waste shells to promote habitat of various small animals, we observed biochemical changes in tank water with the substrata placed within Tsuruga Port for 9 months. Sticking animals that prey on phytoplankton such as bivalves, polychaetes and sea squirts had majority in total 88 species on/in complex cubic body. After adding some diatoms to the tank, the amount of chlorophyll a and SS was rapidly reduced. Their decrease process was almost completed for 12 hours, and then water became transparent visually. Organic carbon and nitrogen was also rapidly decreased, while nitrate nitrogen continued to increase gradually. We estimated that those animals decrease 1.25mg hr^-1 in chlorophyll a, 264.8mg hr^-1 in SS and 2.9mg hr^-1 in organic nitrogen. Its purifying velocity was as 1.7-17.2 times as that of tidelands with corbiculae or clams. Therefore, it is concluded to work more sufficiently as purifying facilities if to put cubic body up.