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.

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This paper describes study results of applicabilites of the catalytic wet-oxidation process (CWOP), which is an advance treatment technique of sewage sludge. Here is an outline of research results:
(1) The CWOP can handle concentrated sludge in the liquid phase without adding any dewatering or drying steps which have been needed in the still widely used incineration disposal and other methods.
(2) The CWOP can treat almost all organic substances and nitrogen compounds in sludge under the reaction conditions of 280°C, 9.12 MPa and 1.5 hr.
(3) The sludge is made soluble first and then low-molecular. It turns into carboxylic acids and aldehydes, and finally becomes carbon dioxide and water.
(4) The treatment efficiency of organic substances and nitrogen compounds is little affected by fluctuations of the initial reaction pH and air feed ratio.
(5) There is no large difference in the treatment efficiency of components between different types of sludge.
(6) A trial calculation of heat balance in the CWOP shows that about 70% of the heat of the reaction (thermal energy) through decomposition of organic substances and nitrogen compounds in the sludge is expected to be recovered.
(7) The CWOP still has some problems to be solved. One is to find optimum intervals of chemical cleaning to eliminate from the reaction system metallic oxide deposits which are caused through a long-term continuous run. The other is to evaluate the durability of catalyst in the course of treatment run.

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A Neural Network (NN) based on back-propagation algorithm is proposed to predict the coke consumption in a melting furnace, and to control the coke charge automatically. This new-type melting furnace with pulverized dried sludge injection has been developed to enhance the performance of the conventional coke bed melting furnace. Numerous operating conditions and measured data of bench-scale experiments are used as learning data to determine the network architecture and parameters. It should be noted that there is a significant drop in the computing time to implement the network model and perform simulation using the network model compared with the mathematical model. The results predicted by the network model are in reasonable agreement with the actual measurement data and the results by the mathematical model, suggesting the effectiveness and applicability of this model to predict the performance of melting furnace and to control the coke charge automatically. In addition, the network model is utilized to investigate the influence of such operating conditions as the sludge charge rate on performance of the bench-scale melting furnace.

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Although scallops are one of the major products of the fishery industry around Hokkaido island, the treatment of waste scallop shells has been becoming an important subject from the environmental point of view because of a limitation of the space for reclamation and the bad smell they emit. Utilization of the shells in industries as a calcium source is the most desirable means for solving the above problems.
In the present paper, calcination of scallop shell to produce quick lime was examined using an experimental fluidized bed reactor having a 0.16m inner diameter. Sieving the crushed shell to a maximum size of 3 mm brought about a smooth fluidization state and steady operation of the calciner. For the products withdrawn from the bottom of the fluidized bed calciner, a high calcination ratio has attained as high as over 99% at a calcination temperature of 850°C and a mean residence time in the calciner of 80 minutes. Reactivity and performance of sulfur dioxide absorption of the quick lime from the shell were measured and the results were compared with those values for quick lime from limestone. Excellent performance of sulfur dioxide adsorption was found for the quick lime from the shell, and this is obviously caused by a bigger mean size of the pores formed by calcination.

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The supercritical fluid extraction method using carbon dioxide was investigated from the viewpoint of the relationship between the recovery of organic pollutants in the model waste sample and extraction parameters. Chlorobenzenes were selected as target compounds because they are considered to be priority pollutants. Extraction was almost completed within 30 min under the flowrate of ca. 1ml/min on model sample. The pressure which determines the density of fluid under the constant temperature essentially affects extraction efficiency with increased recovery in the region of high pressure. However, extraction recovery does not simply depend on the increase of pressure, the effect of temperature is also observed. It is expected that the volatilization effect contributes to achieving high extraction efficiency for volatile and thermally stable compounds. Though the addition of a polar modifier increases extraction efficiency, the effect is influenced by interaction between the analyte-matrix complex and the bulk of supercritical fluid. The application of supercritical fluid extraction to real fly ash sample demonstrates that this method is not sufficient for accomplishing quantitative extraction. Further problems were also discussed.

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