Effectiveness of Foamed Waste Glass as a Contaminated Tidal Mud Improvement Material

摘要

Recycled waste glass (Foamed waste glass) has a great extent of utilizations in construction engineering from the beginning of its production. This study shows a new utilization of this foamed waste glass as an improvement material for the contaminated tidal flat mud in the Ariake sea, Japan. The Ariake sea tidal flat mud which is 40% of the total tidal area of Japan is famous for its various kinds of fisheries products and sea weed cultivations. However, a dramatic declination of catch of shells is observed for the last 3 decades in the Ariake Sea. The unfavorable geoenvironment and the high sulphide content is the most liable for this declination of catch of shells. To restore the Sininovacula constricta shell in the Ariake Sea an artificial fishing land for that shell was created by improving the tidal mud. A specified quantity of foamed waste glass (5 %) and sand (15%) were mixed thoroughly with the tidal mud improvement area (25 × 40 m). Then Sinonovacula constricta was discharged into the artificial fishing land. The regular monitoring of the geoenvironmental condition was carried out once a month by collecting the samples by 0.90 m long and 0.070 m diameter steel tube sampler. It was seen that the sulphide content has remarkably reduced as the new mixing of the tidal mud with foamed waste glass and the sand has ensured the aerobic condition by easily movement of fresh sea water. The foamed waste glass can be used as an improvement material for the restoration of the unfavorable tidal flat mud.