Chemistry of Fluoride Leaching and Associating Influential Factors in Plaster Board Waste

Plaster board waste generated from industries, usually contains major proportion of calcium as calcium sulfate. In addition, fluoride is remarkably one among the constituents of this waste material. Experimental studies were conducted to determine the fluoride leaching as a function of particle size, pH of leaching solvent (distilled water) and water: PBP ratio. The influence of sodium salts on the leaching of fluoride from PBP was studied. It was explored that one gram of plaster board waste contains 18.54 mg F per gram of PBP. High leaching of 3.70 mg F per liter was studied at pH 6.02 with Ca2+ and TDS contents of 1050 mg L-1 and 1640 mg L-1 respectively. The influence of fluoride leaching by sodium phosphate recorded a high value of 12.75 mg L-1 with no detectable amount of calcium ions. The leaching mechanism was predicted significantly by the exchange of Na+ and Ca2+ ions. The leaching rate as a consequence of shaking and stirring dynamics was also investigated at different conditions

evelopment of "SDGs Shiny Mudball (dorodango)" for teaching "Sustainable and contribution" and achievement of SDGs 4.7

There are few learning materials that can read the history (archive) carved in the soil and mud, look over disaster prevention education and geo-environmental problems in a single relationship diagram, and feel the feeling of the palm. Recognizing geo-environmental problems, experiencing soil and mud, revering soil and mud, and cultivating a "heart that cherishes the earth" means a skill necessary to achieve sustainable development involving SDGs. The authors conducted research and development using industrially adjusted pottery clay to make a learning material for visiting lecture using Shiny Mud Ball to achieve Sustainable Development Goals (SDGs). "SDGs Shiny Mud Balls" certainly enable everyone to get excitement and pleasure that shine or polish is obtained in a short period of time. "Contribution" of the SDGs can be understood by "SDGs Shiny Mud Balls"

Forest Cover Change and Soil Erosion in Toledo\u27s Rio Grande Watershed

Toledo, the southernmost district, is the hub of Belize\u27s Mayan population, descendants of the ancient Mayan civilization. The Toledo District is primarily inhibited by Kekchi and Mopan Mayans whose subsistence needs are met by the Milpa slash-and-burn agricultural system and the extraction of forest resources. The poverty assessment in the country indicates that Toledo is the district with the highest percentage of household an individual indigence of 37.5 % and 49.7 % respectively. Forest cover change in the area can be attributed to rapid population growth among the Maya, together with increase in immigration from neighboring countries, logging, oil exploration and improvement and construction of roads. The forest cover change analysis show that from 2001 to 2011 there was a decrease of Lowland broad-leaved wet forest of 7.53 km sq, Shrubland of 4.66 km sq, and Wetland of 0.08 km sq. Forest cover change has resulted in soil erosion which is causing the deterioration of soils. The land cover types that are contributing the most to total erosion in the Rio Grande watershed are no-forest, lowland broad-leaved wet forest and submontane broad-leaved wet forest. In this study the Revised Universal Soil Loss Equation (RUSLE) was employed in a GIS platform to quantify and assess forest cover change and soil erosion. Soil erosion vulnerability maps in Toledo\u27s Rio Grande watershed were also created. This study provides scientifically sound information in order to understand and respond effectively to the impacts of soil erosion in the study site.2015 36th International Symposium on Remote Sensing of Environment; Berlin; Germany; 11 May 2015 through 15 May 201

中間土の圧縮および強度特性に関する基礎的研究

第1章 序論 第2章 応力分担割合の評価に基づく二種混合体の応力-ひずみ関係 第3章 中間土の骨組構造と応力-ひずみ関係の基本式 第4章 中間土の圧縮特性 第5章 中間土の強度特性 第6章 総括Made available in DSpace on 2012-07-10T07:15:26Z (GMT). No. of bitstreams: 1 omine.pdf: 14102453 bytes, checksum: 63cc1efb990bc3f33689f6d7088c3531 (MD5) Previous issue date: 1993-02-22主1-参1工学_環境都

Seasonal Variation of Contaminated Geo-Environmental Condition of Yamaguchi Bay Tidal Flat, Japan

In this study, the seasonal variation of geo-environmental condition of Yamaguchi Bay tidal flat has been studied. Yamaguchi bay is located at the south part of Yamaguchi prefecture and was famous for its different kind of shells and other living creatures. However, a sharp declination of a catch of shells and crabs have been observed in recent years. Particularly, the living creatures related to the tidal flat mud have been suffered a damage. Recently, the horseshoe crabs which used to come onto shore to mate is declining in Yamaguchi bay which is not good for the marine ecosystem of this area. The mud samples were collected from the tidal flat area once in every month by using the tube sampler. Then the samples were cut into specified layer and measured the different geo-environmental parameters (acid volatile sulfide, pH, loss on ignition, COD, Electrical conductivity) at the laboratory in each layer. It was observed that the acid volatile sulfide (AVS) which is the most important parameter for the living condition of the living creatures is over the safe limit (0.2 mg/g-dry mud) during the summer. The other parameters such as pH, LOI, have also significant variation in different seasons but they were still within the safe limit. The COD value of the tidal mud also showed a significant variation during the summer and the winter. However, the higher AVS value was one of the reasons for the declination of horseshoe crabs and other living creature in the tidal flat of Yamaguchi bay, Japan

Preliminary study and prospects on the dewatering behavior of the dredged slurry with horizontal drainage layers by siphon method

Abstract: The disposal of the dredged mud has become a worldwide problem recently. There are urgent demands for developing alternatives to dispose the dredged material in a more economical and environment-friendly manner. In this paper, the horizontal drainage layer with siphon method is proposed to dewater the dredged slurry. The preliminary dewatering tests are conducted to investigate the dewatering and strength behavior of the dredged mud with horizontal drainage layer. On the basis of the test results, the further research work on the proposed method is prospected