Three questionnaire surveys were carried out in order to clarify the current status of household hazardous waste (HHW) generation, collection, and disposal. The survey was conducted amongst residents in the city of Sapporo, it covered 470 municipalities and 185 waste management companies also took part. Fourteen groups of target products were selected based on a list provided by the US EPA, and specific questions were asked for each individual group.
Although municipalities show the source-separation categories in a pamphlet distributed to residents, the categorization system is not standardized and varies among municipalities. In some cases, HHW is classified under just two categories, either combustible or non-combustible waste, which shows a lack of understanding regarding the hazardous nature of some of these wastes. Residents do not pay much notice to information given out by municipalities. When products are assigned to the non-collection category, which means that municipalities are not responsible for pick up, a portion of the residents merely disposed of their HHW along with other non-hazardous wastes. Municipalities must provide contact information for how to dispose of items that fall into the non-collection category, such information is not sufficient at present. In addition, half of the waste management companies do not accept HHW even though they are on the contact list being circulated.

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This study presents factors influencing household waste generation per capita in two local towns. Points such as household waste composition, trash-bag weight, frequency of waste discharge and social behaviors related to waste reduction were investigated using a field survey and questionnaire. Combustible household waste became the main focus for this study due to its significant contribution to total household waste volume. Factors such as ratio of self-disposal, weight of discharged household waste and waste-bag discharge totals per day per capita were found to vary between the two towns. A difference of approximately 1.8 times the estimated amount of combustible household waste generation per capita between the two towns was revealed. Influencing factors on household waste generation per capita in these towns were investigated using the quantification theory type I. It was found that self-disposal, the number of people per household and occupation influenced the generation of household waste. In particular, self-disposal of yard waste significantly influenced this difference in waste generation between the two towns. In order to further reduce waste generation in local towns, food and yard waste composting at the home is effective.

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Food wastes from households were treated with steam at 150 °C for 40 minutes (150SFW) or at 200 °C for 150 minutes (200SFW), and the possibilities of developing the resulting materials into livestock feeds were researched. Both SFWs were shown to be composed about 20% of proteins and 20% of lipids, which are higher than the ratios of commercial diets for finishing pigs. On the other hand, pepsin digestibility of both SFWs was 26-56%, which was lower than that of a commercial diet. To estimate the applicability of SFWs as feed, eight pigs, each weighing approximately 70kg, were divided into test and control groups of four pigs each. In the test group, the pigs were fed diets that were 20% 200SFW for an initial 29 days and were subsequently fed diets that were 15% 150SFW until they reached 110±5kg. Pigs were fed diets without SFWs in the control group. The daily gains (DG) of two pigs in the test group were similar to those of pigs in the control group through the test period. The other two pigs in the test group had relatively lower DG when 200SFW was given, but ultimately reached 110±5kg 29-46 days later than pigs in the control group.

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In order to examine the effectiveness of resistivity measurements for inferring the internal conditions of landfills, we carried out a scale experiment. The container that we used for the experiment was 1.8m long, 1m wide and 0.5m deep. Its bottom was divided into 9 cells with 2 drainpipes. The fill was composed of gravel, incinerator ash and sand in ascending order. 17 electrodes were buried in the ground surface at 10cm intervals along a resistivity profile line. The fill was periodically sprinkled with water. Resistivity measurements were carried out by the dipole-dipole method and the quantities and qualities of leachate from each cell were measured. As a result, an inverse correlation between the electrical conductivity of the leachate and the resistivity of fill was found. A zone identified as having a high resistivity ratio was located above a cell with large drainage volume. In addition, the above results were compared with field monitoring data from an actual landfill.

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This paper focuses on the heat treatment conditions of waste oyster shells in order to use them as an adsorbent material for ions with negative environmental impacts, such as phosphate, sulfate and cadmium ions. The effective processing of oyster shell surfaces was successfully achieved at temperatures as low as 600 °C with the appropriate nitrogen flow rate. In ion removal tests using oyster shells heat-treated by the proposed method, their ion removal abilities were highest for cadmium, followed by phosphate and then sulfate in order.

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