Analysis of Experimental Solar Radiation Data for Osogbo, Nigeria

An analysis of measured global solar radiation (GR) in Osogbo (7.77oN, 4.57oE, 288m) is presented in the form of hourly average, monthly average and percentage frequency distribution. The experimental data corresponds to a year data of 2017. The results reveal that the monthly average values of daily total radiation exhibit seasonal variation with maximum value in dry season month of March (16.59MJ/m2) and minimum value in wet season month of August (8.98 MJ/m2). The annual average GR value is 14.20 MJ/m2 while the annual cumulative GR is 5122 MJ/m2. The solar radiation climate of Osogbo has also been compared to those reported for a number of locations. The percentage frequency of days possessing irradiation rate greater than 15 MJ/m2 is 14 percent whereas that possessing less than 10 MJ/m2 is 61 percent. We conclude, based upon the above analysis that Osogbo is characterized by relatively low global solar radiation. Keywords: Global solar radiation, Cumulative frequency, Measured, Season

Environmental impact on the bacteriological quality of domestic water supplies in Lagos, Nigeria Impacto ambiental sobre a qualidade bacteriológica do abastecimento domiciliar de água em Lagos, Nigéria

OBJECTIVE: To assess the impact of town planning, infrastructure, sanitation and rainfall on the bacteriological quality of domestic water supplies. METHODS: Water samples obtained from deep and shallow wells, boreholes and public taps were cultured to determine the most probable number of Escherichia coli and total coliform using the multiple tube technique. Presence of enteric pathogens was detected using selective and differential media. Samples were collected during both periods of heavy and low rainfall and from municipalities that are unique with respect to infrastructure planning, town planning and sanitation. RESULTS: Contamination of treated and pipe distributed water was related with distance of the collection point from a utility station. Faults in pipelines increased the rate of contamination (p<0.5) and this occurred mostly in densely populated areas with dilapidated infrastructure. Wastewater from drains was the main source of contamination of pipe-borne water. Shallow wells were more contaminated than deep wells and boreholes and contamination was higher during period of heavy rainfall (p<0.05). E. coli and enteric pathogens were isolated from contaminated supplies. CONCLUSIONS: Poor town planning, dilapidated infrastructure and indiscriminate siting of wells and boreholes contributed to the low bacteriological quality of domestic water supplies. Rainfall accentuated the impact.<br>OBJETIVO: Avaliar o impacto do planejamento urbano, da infra-estrutura, do saneamento e dos índices pluviométricos sobre a qualidade bacteriológica do abastecimento domiciliar de água. MÉTODOS: Foi realizada cultura de amostras de água obtida de poços superficiais e profundos, fossos e água corrente de bicas públicas para determinar o número mais provável de Escherichia coli e coliformes totais por meio da técnica de múltiplos tubos. Patógenos entéricos foram detectados pelo uso de meios diferenciais e seletivos. Amostras foram coletadas durante os períodos de seca e de chuvas intensas em municípios com características singulares de infra-estrutura, planejamento urbano e saneamento. RESULTADOS: A contaminação de água tratada ou encanada esteve relacionada à distância do ponto de coleta com relação à estação de tratamento. Defeitos na canalização aumentaram o índice de contaminação (p<0,5), principalmente em áreas densamente povoadas com infra-estrutura arruinada. Os despejos de bueiros representaram a principal fonte de contaminação da água encanada. Houve maior contaminação em poços superficiais do que em fossos e durante os períodos de chuvas intensas (p<0,05). E. coli e outros patógenos entéricos foram isolados de fontes de abastecimento contaminadas. CONCLUSÕES: A falta de planejamento urbano, as más condições de infra-estrutura e a localização indiscriminada de poços e fossos contribuíram para a baixa qualidade bacteriológica do abastecimento domiciliar de água. As águas das chuvas agravaram o impacto