To utilize waste glass fiber-reinforced plastic (GFRP) and to reduce environmental pollution in rivers and lakes, we developed a filtering material that can clean contaminated water. The high strength and porous nature of glass fiber-reinforced ceramic made by mixing clay and crushed waste GFRP before firing was exploited to do so. Various specimens with different pore size distributions were made by changing the mixing ratio of clay and crushed GFRP, the GFRP particle size, and the mixture firing temperature. Bending strength and permeability tests indicated that several types of ceramics with good permeabilities and adequate bending strengths could be produced, which enables their use as filtration materials for turbid water. Filtration tests on simulated turbid water clarified the relationship between the pore size distribution and the filtering ability of the ceramic for turbid water. Filtration tests on river water verified their practical suitability as ceramic filtration materials. It is proposed that ceramics made from clay and GFRP could be used as filtering materials for turbid water.
The arsenic contamination of groundwater in Uttar Pradesh State was first recognized in 2003 and is now seen at 20 Districts out of 70 Districts. University of Miyazaki has performed the arsenic mitigation project in Bahraich District, severest arsenic-affected one in the 20 Districts, from June 2008 until now, with JICA (Japan International Cooperation Agency). The integrated mitigation, such as the raising awareness of villager, installing of alternative water supply units and healthcare of arsenocosis patients, have been executed at the 2 villages. The symptom of the arsenocosis patients was not so severe, which will be, therefore, improved by drinking arsenic-safe water supplied through arsenic removal units, installed by this project. In this paper, following results is discussed for the situation and mechanism of arsenic contamination of groundwater, objected in connection with the installation of arsenic removal units: 1) Groundwater is almost contaminated with arsenic in deep tubewell (depth: about 30 m), but scarcely in shallow tubewell (depth: about 10 m); 2) Arsenic contaminated groundwater is under the reduced condition with the oxidized condition for no-arsenic contaminated groundwater; 3) Arsenic concentration shows almost linear correlation with concentrations of Fe2+ and -N; 4) Ground is composed of sand with high arsenic content at around 25 m depth; 5) Arsenic exists mainly in the phase of reducible fraction or weak acid soluble fraction but no oxidizable fraction in the ground
This study is aimed at the development of civil engineering materials such as pavement blocks and building tiles that can moderate the heat island phenomenon. This is achieved by exploiting properties such as the material porous structure, high water absorption capacity and high strength of ceramics produced by mixing clay and crushed waste glass fiber-reinforced plastic (GFRP) before firing. Fundamental properties, such as pore size distribution, water absorption capacity, solution pH after ceramic immersion, bending strength, freezing resistance performance and thermal conductivity of ceramic specimens with varying ratios of clay and GFRP were clarified. The radiant heat reduction performance of the ceramic was examined by measuring the surface temperatures of a ceramic sample made from clay, a ceramic sample made by mixing 20% GFRP with clay, and a mortar sample in water-saturated and dry states while their surfaces were irradiated with infrared light. To clarify the difference in temperature-reducing ability by evaporation heat on each sample, the amount of water evaporated from a sample that had absorbed water and was irradiated with infrared light was measured. The rate of heat-absorption from the sample by water evaporation was estimated. The temperature-reducing effect by evaporation heat of the sample during water-absorption was verified quantitatively by thermal conductivity analysis using finite element methods. While water-saturated, a 20% GFRP/clay ceramic sample could reduce the increase in temperature caused by radiant heat considerably, and for an extended duration. It is expected that such ceramics could be used in civil engineering materials to counteract the heat island phenomenon.
In March 1997, we analyzed the water of all tubewells used for drinking in Samta village in the Jessore district, Bangladesh. It has been confirmed from the survey that the arsenic contamination in Samta was one of the worst in the Ganges basin including West Bengal, India. 90% of the tubewells had arsenic concentrations above the Bangladesh standard of 0.05 mg/l. Tubewells with higher arsenic concentrations of over 0.50 mg/l were distributed in the southern area with a belt-like shape from east to west, and the distribution of arsenic concentration showed gradual decreasing toward northern area of the village. In order to examine the characteristics of the arsenic distribution in Samta, we have performed investigations such as: 1) the characteristics of groundwater flow, 2) the distribution of arsenic in the ground, 3) the concentration of arsenic and the other dissolved materials in groundwater, and 4) the distribution of arsenic concentration of trivalence and pentavalence. This paper examines the mechanism of arsenic release to groundwater and explains the above-mentioned characteristics of the arsenic contamination in Samta through the investigations of the survey results for these years.
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