Progrès dans le recyclage et la gestion des déchets

Investigation of apatite piezoelectricity was conducted in order to assess piezoelectric properties of bone. In the first stage, mineralogical analysis of different apatite crystals, regarding their purity and fitness for the experiments was performed. After the crystals, had been chosen, 0.8 mm-thick plates were cut, perpendicular and parallel to the crystallographic Z axis. The plates were then polished and dusted with gold. Electrodes were attached to the opposite surfaces of the plates with conductive glue. So, prepared plates were hooked up to the EEG machine used for measuring electrical activity in the brain. The plates were then gently tapped to observe and register currents generated in them. Acquired data was processed by subtracting from the resulting graphs those generated by a hand movement, without tapping the plate. Results indicate that apatite plates have weak piezoelectric properties. Observed phenomenon may be translated to bone apatite, which would explain, at least partially, piezoelectric properties of bone. Acquired results suggest that there is a relation between the mechanical workload of bones (bone apatite) and their electrical properties. Considering the massive internal surface of bones, they may be treated as a kind of internal “antenna” reacting not only to mechanical stimuli, but to changes in electromagnetic field as well. Observed phenomena no doubt significantly influence the biological processes occurring in bones and the whole human body.

The study demonstrates how socio-economic factors and water quality issues have influenced human health (diarrheal and skin infections) concerns in the local communities of Bufundi sub county, south western part of Uganda. The socio-economic factors of concern included level of education, number of people in a household, incomes, water storage, water treatment and water sources. Water appearance, nitrogen compounds, and coli forms in river, spring and gravity water sources were determined. A questionnaire and laboratory analyses were applied to generate data. Results show that the chi-square values for the discriminant function between diseased and nondiseased were 30.95 and 25.48 (p=0.001) for diarrhea and skin infection respectively. Most the respondents (68.9%) obtained their water from river and spring water sources, and 77.4% never covered water drinking containers. Results show total coliforms to be 5 times higher (650 CFU/100 ml) in river water than international standards.

Environmental pollution is big issue in the world, which is from the natural by-products. Some of these byproducts can be transformed into alternative energy source. Rice husk is the one of the natural by-product which is freely available in Sri Lanka that can be used to produce gas for cooking. To utilise the natural by-products a cooker was designed and the performance of the cooker was evaluated. The cooker consists a gasifier, char chamber, air blowing system and a burner. The rice husk was feed into the gasifier through the top of the cooker and lighted. The gas was produced through air force blown into the reactor through the fan to the husk and the atmospheric air from the secondary holes around the burner for proper oxygenation. The performance test was done by boiling 1 litres of water within 7 minutes and the result revealed that the efficiency of the cooker is 27.17%. The efficiency of the cooker could be increased by continuous flow of rice husk feeding. The end product rice husk ash could be utilising as a raw material in cement, bricks and fertilizer production.

This study briefly discussed water hygiene condition in Rural Bekwarra Community. Based on the 5 selected parameters for the experiments, results showed that average permeate Fluoride was 1.6 mg/L, pH of 7.8, average Iron (Fe+3) of 0.7 mg/L, Lead (Pb) of 0.02 mg/L, and Total Dissolved Solids of 578 mg/L. From the results, it showed that only pH had average value within the standard requirement for drinkable water in Nigeria. Thus, there is a considerable need for the treatment and recycling of borehole water in the community before use.

This review shows the pros and cons of using the combination of various technologies for industrial waste water treatment plant. Rapid industrialization, intensive agriculture and other human activities cause soil degradation, pollution and lowers the productivity and sustainability of the crops that further increase the pressure on natural resources and contribute to their degradation. Environmental bio remediation is an effective management tool for managing the polluted environment and in restoring the contaminated soil. The use of microbial sources, coupled with advanced technology is one of the most promising and economic strategies for the removal of environmental pollutants. There is a strong scientific growth with both the in situ and ex situ ways of bio remediation, in part due increased use of natural damping as most of the natural attenuation is due to bio degradation. The degradation of pollutants by environmental bio remediation technology, can be a lucrative and environmentally friendly alternative. This article provides an overview of the important environmental bioremediation technologies and their application in treating the industrial waste water.