Aggravated by rapid population growth, urbanization, and industrialization and most recently by climate change events, the availability of water especially in the third world is reaching critical proportions.  This is aggravated by the non treatment of wastewater (sewage) and discharged of untreated wastewater into water bodies. The study focused on identifying and reviewing four wastewater treatment methods from a sustainability perspective; waste stabilization pond, constructed wetland, up-flow anaerobic sludge blanket reactor and sedimentation/thickening tank systems suitable for the Limbe Urban Municipality (LUM) of Cameroon in Central West Africa with an estimated population of 120, 000 inhabitants and experiencing 4.7 per cent annual growth rate. The attractiveness of these four methods stems from their apparent energy efficiency, simplicity, robustness, low cost effectiveness in situations where as in the LUM, there are huge tracts of available land, warm temperatures, and their capacity to promote effluent re-use opportunities for various sectors. Issues of sustainability of the water supply and wastewater treatment systems, untreated sewage, and their contribution to escalating environmental and public health impacts in LUM (Cameroon) were critically evaluated and discussed with the aid of Kärrman (2000) framework approach that employs different sets of sustainability criteria (Environmental, Health and Hygiene, and Functional), sub-criteria and indicators. Results obtained reveal that water and wastewater treatment systems in LUM do not operate or conforms to sustainability perspectives. Inhabitants do not still have access to clean drinking water (an approximate 45 per cent) especially in the dry periods of the year, low sanitation coverage (with the tradition of sewage treatment in septic tanks and pit latrines), rising yearly public health impacts associated with water-borne (cholera, dysentery, malaria, typhoid fever and diarrhea) infections and 6 deaths reported in LUM. These leading problems are directly or indirectly linked to consumption of contaminated water or foods in different communities such as Mile II, Isokolo, Bonadikombo (Mile four) etc, and New Town areas and flood prone zones in the Limbe urban municipality.

<p>This research is carried out to explore the factors that influence visitors to choose a particular destination for a visit or the attributes visitors consider necessary to quality a place as a potential destination for a visit. This research is a comparative study on tourism destination marketing conducted in a town in a developed country; Gotland Island in Sweden and a town in a developing country; Limbe city in Cameroon. This research tries test two hypothesis, which were formulated by the researcher.</p><p><em>Hypothesis I</em>; visitors consider particular attributes in a destination before they visit it.</p><p><em>Hypothesis II</em>; some attributes are inevitable in any destination choice decision.</p><p>The research contains ideas from 200 respondents, 100 visitors of Gotland Island, and 100 visitors of Limbe City, and the results support both hypothesis. The research also contains a comparison of the attributes visitors consider in Gotland Island and Limbe city. This brings out the factors that would be considered by visitors in a developed country and visitors in developing country.</p>

This research is carried out to explore the factors that influence visitors to choose a particular destination for a visit or the attributes visitors consider necessary to quality a place as a potential destination for a visit. This research is a comparative study on tourism destination marketing conducted in a town in a developed country; Gotland Island in Sweden and a town in a developing country; Limbe city in Cameroon. This research tries test two hypothesis, which were formulated by the researcher. Hypothesis I; visitors consider particular attributes in a destination before they visit it. Hypothesis II; some attributes are inevitable in any destination choice decision. The research contains ideas from 200 respondents, 100 visitors of Gotland Island, and 100 visitors of Limbe City, and the results support both hypothesis. The research also contains a comparison of the attributes visitors consider in Gotland Island and Limbe city. This brings out the factors that would be considered by visitors in a developed country and visitors in developing country.

L'assimilation de données permet de combiner d'une manière optimale un modèle numérique décrivant l'évolution de la composition chimique de l'atmosphère et les mesures disponibles. Dans cette thèse, l'assimilation de données est utilisée afin de caractériser les distributions troposphériques et stratosphériques de l'ozone (O3) et du monoxyde de carbone (CO). Le Modèle de Chimie Transport (CTM) MOCAGE (MOdèle de Chimie Atmosphérique à Grande échelle) est utilisé dans une configuration à deux domaines imbriqués avec les résolutions de 2◦ (global) et de 0.2◦ (régional). La technique variationnelle du 3D-FGAT est utilisée pour toutes les études que constituent cette thèse. Nous avons évalué la complémentarité des mesures satellites au limbe et au nadir aujourd'hui disponibles pour la caractérisation de l'UTLS (Haute Troposphère Basse Stratosphère) en assimilant ces deux types de mesures simultanément. Nous nous sommes en particulier intéressé à la propagation de l'information provenant des mesures assimilés dans le modèle et plus particulièrement, aux impacts de l'assimilation de mesures stratosphérique d'ozone en troposphère aux moyennes latitudes. Les principaux objectifs de cette thèse ont été de montrer la valeur ajoutée de l'augmentation de la résolution modèle pour l'assimilation de données et les effets synergiques de l'assimilation combinée d'un sondeur au limbe et au nadir. Des développements au niveau du système d'assimilation en domaine imbriqué à 0.2◦ ont été effectués. L'assimilation des données dans le domaine global est maintenant prise en compte et les conditions aux bords provenant des champs assimilés montre un impact significatif sur le domaine imbriqué. Dans un premier temps, nous avons assimilé les profils d'ozone stratosphériques mesurés au limbe provenant de MLS (Microwave Limb Sounder) afin d'étudier deux cas d'échange entre la Stratosphère et la Troposphère (STE). / Data assimilation combines in an optimal way a numerical model describing the evolution of the atmospheric chemical composition and the available trace gases measurements. In this thesis, data assimilation is used to characterize the ozone (O3) and the carbon monoxide (CO) distributions in the stratosphere and in the troposphere. The Chemistry Transport Model (CTM) MOCAGE (MOdèle de Chimie Atmosphérique à Grande Echelle) is used in a configuration with two nested domains at 2◦ (global) and at 0.2◦ (regional). To perform the assimilation experiments a 3D-FGAT variational method is used. We evaluate the complementarity of limb and nadir measurements available at the present day at characterizing the UTLS (Upper Troposphere Lower Stratosphere) region by assimilating simultaneously the two type of measurements. We particularly focus on the impacts of data assimilation of stratospheric ozone measurements on troposphere and conversely of tropospheric data assimilation on stratosphere. Showing the added value of the increased horizontal resolution in the UTLS assimilated fields and the synergistic effects of limb and nadir assimilation were the main objectives of this work. Development in the assimilation system have been made in the assimilation system with the nested domain. Data assimilation in the global domain is now taken in account and the boundary condition from the assimilated fields show significant impacts on the regional domain. Firstly, we assimilate stratospheric ozone profiles from MLS (Microwave Limb Sounder) to investigate two Stratosphere-Troposphere Exchange (STE) case studies. .