Adsorption parameters such as the distribution coefficient are required to predict the release behavior of contaminants using advection-dispersion models. However, for potentially contaminant-releasing materials (PCMs) such as dredged sludge and coal ash, these parameters cannot be obtained by conventional adsorption tests. This study developed a method to determine adsorption parameters for PCMs from a set of batch tests conducted in parallel as a function of the liquid-solid ratio (LS-parallel test). This LS-parallel test was performed on sandy soil derived from marine sediment using liquid-solid ratios from 1 to 300 L/kg. The water-contact time was also changed from 10 min to 28 d to elucidate the kinetics or equilibrium of contaminants released from the sample. Adsorption parameters were successfully obtained if the substance was under adsorption control. A column percolation test was performed to confirm the effectiveness of the obtained parameters. Good agreements were observed for SO₄²⁻ and B, but discrepancies remained for other substances such as F⁻ and As suggesting that improvements are necessary in both the LS-parallel test procedure and the advection-dispersion model.

This study aims to obtain findings on the internal water behavior, the presence of water channels, and the degree of washout due to rainfall infiltration in Japanese municipal solid waste (MSW) final disposal sites. Electrical resistivity tomography (ERT) monitoring and undistributed waste sampling for X-ray computed tomography (X-ray CT) analysis were conducted in the field. The study sites were targeted at Site A, which is mainly composed of non-combustible residues, and Site B, which is mainly composed of incineration ash. The time-dependent resistivity distributions obtained from real-time ERT monitoring were effective for us to understand the water content distribution after water infiltration during water injection tests. As a result, the global flow behavior and the local water channel flow were determined. In addition, X-ray CT analysis of the undisturbed waste samples obtained from the sites clarified the different pore structures, indicating the possibility of more advanced washing out at Site A than at Site B. Furthermore, the soil cover layer and gas extraction wells had a significant effect on the resistivity structure with respect to water flow behavior. Since soil cover layer and gas extraction wells are significant factors affecting waste stabilization by washout, it is suggested that these factors should be considered in the design and maintenance of landfills.

Waste-to-energy technology has proven effective in reducing the mass and volume of waste, thereby minimizing contamination sources and residual fractions. However, high moisture content in waste significantly reduces the efficiency of energy recovery. Biodrying has shown great potential for moisture reduction through microbial activity, enhancing the efficiency of waste-to-energy processes. While the lack of proper real-time monitoring methods hinders the optimization of the biodrying processes. This study proposes an efficient method for monitoring the biodrying of municipal solid waste based on real-time electrical resistivity monitoring. During biodrying, resistivity was measured alongside key parameters like temperature, weight, gas emissions from the biodrying process, relative air humidity, moisture, and waste density. The results indicate a good correlation between bulk electrical resistivity (441–614 Ω·m) and temperature increases above ambient within the first 36 h (r² = 0.97–0.99). Statistical analyses also revealed the correlations of electrical resistivity with waste density (negative correlation, r² = 0.68–0.97) and gas emissions (moderate to strong, r² = 0.45–0.72) during different biodrying phases. These findings demonstrate the relationship between electrical resistivity and key biodrying parameters, which can be used for the development of biodrying and to enhance process control efficiency, thus enhancing sustainable waste management efficiency.

本研究では遮断型最終処分場の長期的な環境安全性の向上を目的とする。ばいじんや汚泥等の特別管理廃棄物からの溶出速度を低減するための措置に着目し，セメント系材料または酸化マグネシウムを用いた固型化処理の効果を長期溶出試験によって明らかにした。ここで得た実験データを遮断型処分場の安全性評価シミュレーション等に応用できるように，固型化処理した重金属等の溶出特性を見かけの拡散係数でパラメータ化した。特別管理廃棄物相当のばいじんと汚泥にはセメント固化を阻害するような重金属や有機物が多分に含まれていたため，高炉セメントB種を最大380 kg/m3添加しても固めることができなかった。圧縮強度0.98 MPaを満たすことは容易ではなく，溶出試験時に浸漬した時点で形状が崩れるものもあった一方で，酸化マグネシウムを用いた場合，浸漬によって形状が崩れたとしても重金属等の高濃度溶出を防ぐことができた。

本研究では廃棄物埋立層からの浸出水濃度を予測するための数理モデル構築とそのモデル検証を行なった。特に予測が難しいと考えられる高濃度の化学物質を含有する特別管理産業廃棄物を対象に検討した。数理モデルは，シリアルバッチ溶出試験の結果を溶出モデルとして加えた移流分散方程式である。本法の課題の一つは，シリアルバッチ溶出試験が液固比 10 での評価であるのに対して，予測対象となる埋立層ではより低い液固比での溶出挙動であり，それをどのように数理モデルに反映させるのかである。本研究では，実用面に優れたモデル構築と高精度化を図るため，液固比を変えたバッチ溶出試験を行い，低液固比での実測値と予測値の差異を調べることで溶出モデルに与える補正係数を導出した。補正係数を用いた数理モデルの有効性を明らかにするためにカラム溶出試験を実施したところ，アルカリ金属とアルカリ土類金属には高精度な予測を与えることがわかった。