Effluent Water Quality of a Stable-type Waste Disposal Site

In order to elucidate environmental effects of a stable-type disposal site for industrial wastes, the effluent water quality of Miyamoto disposal site in Niigata Prefecture was studied from July, 1992 to November, 1993. As a result, amounts of electroconductivity, permanganate value and total nitrogen exceeded the criteria for agricultural water. The TOX concentration was much higher than the control. Most of the TOX was found to consist of non-volatile compounds. The biodegradability of effluent reached only 30% of the initial COD (Cr) of effluent. Microtox-toxicity was also found in the effluent only when samples were concentrated under pH2 condition. Mutagenicity was also found only when sample concentration was carried out under pH2, TA 100 strain was used and S9 mix was added. Pollution loads per day of BOD, Permanganate value and total nitrogen in the effluent were equal to those produced by 943, 5600 and 2950 persons per day, respectively, which were amounts that were equal to or more than the number of Miyamoto Town residents. The amounts of seven metals in sediments were much higher than the control. Though both concentration and load of effluent decreased gradually with time during the above-mentioned study period, more careful watching will be needed.