| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Water quality of drainage from 8 stable type and 2 control type of industrial waste landfills were monitored. Through investigation, the followings were found : In spite of after treatment, the concentrations of water quality (EC,COD,T-N) of drainage water from control type of industrial waste landfills were very high compared to those of stable type landfills.
The water quality of the leachate from the stable type landfills was in the range of 5-50mg/l for COD and 2.5-10mg/l except for the Teradomari landfill. When investigation was started in 1992, the COD and T-N concentration of the leachate from Teradomari landfill exceeded 70mg/l and 75mg/l respectively. These values were very high compared to irrigation water quality standard (COD : 6mg/l, T-N : 1mg/l), so paddy rice irrigated contaminated water received serious damage.
From the data of yearly drainage water concentration changes for 2 landfills Teradomari and Narisawa, it was found that water quality concentration changes could be presented by logarithmic regression formula. It become possible to predict the period of water quality recovery. For the most polluting Teradomari landfill, it was predicted that it would take 15.4 years for T-N,8.5 years for COD,and 11.9 years for EC to reach irrigation water quality standard from the time the landfill got filled up and was covered with soil.
Water quality concentration of drainage from landfills filled up had regression trend, but water quality also changed with the affection of rains. A tank model had constructed for prediction of flow and water quality of leachate from stable landfills. Using this tank model the leachate with the slow response for rains and water quality with quick response for rains.
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