Sanitary mapping of well waters in the commune of Bimbo in the Central African Republic (CAR)

This study concerns the strategies for controlling and monitoring the quality of well waters consumed by the population of Bimbo, in the Central African Republic. The majority of the population has no access to clean, safe drinking water, and the distribution network of drinking water only reaches around 20 % of the urban population in the town centre. A population explosion in the Central African Republic has led to a very strong rural exodus, which has resulted in increasing consumption of poor quality drinking water. Futhermore, the virtual absence of a system for collecting wastewater only serves to increase the vulnerability of these shallow reservoirs. Such constraints are common in large African cities, where around 80 % of the population live in areas that have become urbanised in an ad hoc fashion. In such contexts, it is extremely difficult to reconcile groundwater extraction with public health

Elimination of turbidity and bacterial contamination in natural water sources (Ubangi river, Central Africa)

Having access to a natural source of water of sufficiently high quality for human consumption has become a strategic concern for the entire world. In fact, drinking water resources in developing countries are almost non-existent, as they are overused or polluted by intense human activity. Our study aims to develop a natural filter that reduces turbidity and eliminates human pathogens. The process developed should be inexpensive and minimize the use of chemical reagents, and should not be labor intensive. In this context, horizontal sand filtration that uses the natural process of water purification occurring in an aquifer can be regarded as the most suitable water treatment process for developing countries.Disposer d’une source d’eau naturelle de bonne qualité, pour la consommation humaine, est devenu maintenant une préoccupation stratégique pour le monde entier. En effet, les ressources en eaux potables dans les pays en voie de développement sont quasi-inexistantes, car surexploitées ou souillées par une activité humaine intense. L’étude que nous proposons a pour objectif : de mettre au point un filtre naturel qui diminue la turbidité et élimine les agents pathogènes pour l’homme. Le procédé développé peu onéreux devra réduire au maximum l’utilisation de réactifs chimiques, et minimiser toutes interventions humaines. La filtration horizontale sur sable qui utilise le processus naturel de purification de l’eau se produisant dans une nappe aquifère, peut être considéré comme le procédé de traitement de l’eau le plus approprié aux pays en voie de développement et répond aux objectifs fixés.Disponer de una fuente de agua natural de buena calidad, apta para el consumo humano, se ha convertido actualmente en una preocupación estratégica en todo el mundo. En efecto, los recursos de agua potable en los países en vías de desarrollo son prácticamente inexistentes, por exceso de explotación o por contaminación a causa de una actividad humana intensa.El estudio que proponemos tiene por objetivo: desarrollar un filtro natural que reduzca la turbidez y elimine los agentes patógenos perjudiciales para el hombre. El procedimiento desarrollado, de bajo coste, debería reducir al máximo el uso de sustancias químicas reactivas y minimizar cualquier intervención humana. Como la filtración horizontal sobre arena que utiliza el proceso natural de purificación del agua tiene lugar en una capa acuífera, se puede considerar como el procedimiento de tratamiento del agua más adecuado a los países en vías de desarrollo y responde a los objetivos fijados

Sanitary mapping of well waters in the commune of Bimbo in the Central African Republic (CAR)

This study concerns the strategies for controlling and monitoring the quality of well waters consumed by the population of Bimbo, in the Central African Republic. The majority of the population has no access to clean, safe drinking water, and the distribution network of drinking water only reaches around 20 % of the urban population in the town centre. A population explosion in the Central African Republic has led to a very strong rural exodus, which has resulted in increasing consumption of poor quality drinking water. Futhermore, the virtual absence of a system for collecting wastewater only serves to increase the vulnerability of these shallow reservoirs. Such constraints are common in large African cities, where around 80 % of the population live in areas that have become urbanised in an ad hoc fashion. In such contexts, it is extremely difficult to reconcile groundwater extraction with public health

Etude Hydrogéochimique des Eaux Souterraines dans la Formation Gréseuse de la Région de Berberati en République Centrafricaine

La population de la République Centrafricaine est inégalement repartie: les zones ouest et sud montrent une densité de population beaucoup plus haute que la partie Est. Pour parvenir à une meilleure connaissance des ressources en eau en présence, la compréhension des conditions de recharge des formations gréseuses et leur interrelation avec les cours d'eau environnants et leur reservoirs constituent les principales lacunes à combler par ce projet. L’étude porte donc sur l’évaluation des ressources en eaux dans la formation gréseuse de Berberati par l’utilisation des techniques hydrogéochimiques de et l’hydrologie isotopiques.The population of the Central African Republic is unevenly distributed: the western and southern zones show a much higher population density than the eastern part. To gain a better understanding of the water resources present, understanding the recharge conditions of grès formations and their interrelation with the surrounding watercourses and reservoirs are the main gaps to be filled by this project. The study therefore focuses on the evaluation of water resources in the Berberati grès formation through the use of hydrogeochemical techniques and isotopic hydrology

Sanitary mapping of well waters in the commune of Bimbo in the Central African Republic (CAR)

This study concerns the strategies for controlling and monitoring the quality of well waters consumed by the population of Bimbo, in the Central African Republic. The majority of the population has no access to clean, safe drinking water, and the distribution network of drinking water only reaches around 20 % of the urban population in the town centre. A population explosion in the Central African Republic has led to a very strong rural exodus, which has resulted in increasing consumption of poor quality drinking water. Futhermore, the virtual absence of a system for collecting wastewater only serves to increase the vulnerability of these shallow reservoirs. Such constraints are common in large African cities, where around 80 % of the population live in areas that have become urbanised in an ad hoc fashion. In such contexts, it is extremely difficult to reconcile groundwater extraction with public health

Surface characteristics of the iron-oxyhydroxide layer formed during brick coatings by ESEM/EDS, ²³Na and ¹H MAS NMR, and ToF-SIMS

Brick made locally by craftsmen in Bangui (Central African Republic) was modified first by HCl activation and second by iron-oxyhydroxide impregnation through the precipitation of ferric ions by NaOH at various fixed pH values (ranging from 3 to 13). The elemental analyses of synthesized compounds were performed using ICP-AES, and their surface chemistry/properties were investigated by environmental scanning electron microscopy (ESEM/EDS), 1H and 23Na MAS NMR spectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The evidence of different 23Na chemical environments and the coexistence of Si and Al bound to ferrihydrite were made. The surface properties of this material which was found to be dependent upon synthesis pH, contributed to enhance metal uptake from water

Assessment of the effect of Artemisia annua leave extract infusion pH under dark conditions on Staphylococcus aureus, Salmonella paratyphi and Escherichia coli

Objectives: The influence of abiotic factors of water which may affect Artemesia annua (A. annua) efficiency as a disinfectant is not clearly elucidated. This study aimed to assess the potential effects of various water pH values of the infusion of A. annua leaves extract on some bacteria of hygiene and sanitary evaluation. Methodology and Results: A. annua leaves were collected in Bangante (West region, Cameroon) and bacteria were isolated from the surface water (lotic hydrosystems) in Yaoundé (Cameroon, Central Africa). The bacteria used were S. paratyphi, S. aureus and E. coli. Experiments were carried out in aquatic microcosms under dark conditions. The pH values considered were 4, 5, 6, 7, 8 and 9. These values were adjusted using diluted HCl and NaOH. The results showed the temporal changes of cell abundance from one bacteria species to another with respect to the pH value in one hand, and also with respect to the number of cell species in solution on the other hand. In monospecific culture condition, the extract of A. annua seemed to appear as a source of carbon and energy for bacteria growth. In mixed cultures the influence of pH in the presence of the extract of A. annua in the dark seemed to foster trophic relations among bacteria in some cases and stimulate the production of inhibitory substances in other cases. Conclusions and application of findings: Molecules contained in the extract of A. annua were potentially implicated in the physical and chemical changes of the medium, enabling the cell growth observed. A. annua extract did not have a significant bacterial inhibitory property in the water in the darkness. Although A. annua extract is often used as antibacterial component, it should not be used in the bacteriological treatment of drinking water under dark condition whether the water pH is acidic, neutral or alkaline. Key words: A. annua extract, water pH, S. aureus, S. paratyphi, E. coli, temporal abundance, variation

Performance of FeOOH-brick based composite for Fe(II) removal from water in fixed bed column and mechanistic aspects

International audienc

Effects Of Chemical Activation on Surface Sites of The Brick: pH-Dependence on Metal Adsorption

Brick was coated with ferrihydrite under variable experimental (pH) conditions. Pore ndash size distributions were determined and basic functions formed at brick surfaces were differentiated and quantified using pHmetry and conductimetry. Lead(II) and iron(II) adsorption capacities of synthesized compounds were tested by conducting fixed ndash bed column experiments. Both a higher pH used for Fe(III) precipitation into ferrihydrite and a higher level of deposited iron contributed to improve the adsorption performance of this material. The number of generated XiAlO-, XiSiO- and XiFeO- sites was found to be the key factor controlling the adsorption capacity level, and not physical and textural parameters