African Journal of Environmental Science and Technology最新文献

{"title":"An analytical assessment of climate change trends and their impacts on hydropower in Sondu Miriu River Basin, Kenya","authors":"W. Ochieng, C. Oludhe, S. Dulo, L. Olaka","doi":"10.5897/ajest2021.3064","DOIUrl":"https://doi.org/10.5897/ajest2021.3064","url":null,"abstract":"Hydropower is cost effective environment friendly and worldwide proven sustainable energy source. Driven by streamflow stream flows, it is vulnerable to climate change and land use change. The hydropower production from the two-existing run-of-river hydropower projects on the Sondu Miriu River are vulnerable to rainfall variability and requires proper understanding of the climate change trends and policies to support sustainable hydropower development and put in place strategies for building resilience for the local communities. The objective of this paper is to examine climate change trends and their impacts on hydropower in the Sondu Miriu River basin. The methodology involved analysis of downscaled climate data from CORDEX for the period from 1950 to 2100, gridded data from Kenya Meteorological department for a period of 2007 to 2018, river flows data from Water Resources Authority for a period of 2007 to 2018 and hydropower output data from KenGen for a period of 2007 to 2018 to examine the climate change trends within the Sondu Miriu River basin and impacts on hydrology and hydropower. The results indicate that maximum and minimum annual temperature increased by 0.7 and 0.9°C, respectively between 1950 and 2005. Both the maximum and minimum annual temperatures are projected to increase by 1.9°C based on the RCP4.5 and RCP8.5 scenarios between 2006 and 2100 within the Sondu Miriu basin. Annual rainfall increased by 74.8 mm between 1950 and 2005. This is projected to increase by 24.7 and 117.8 mm based on RCP4.5 and RCP8.5 scenarios, respectively. For the period between 2007 and 2018, the observed maximum increased by 5°C while the minimum temperatures decreased by 1°C. The rainfall decreased by 193.14 mm while the mean daily river flows decreased by 0.3 m 3 /s annually during the same period. This resulted in the decrease of hydropower production by 8.3 GWh in Sondu Miriu HPP between 2007 and 2018 while the production reduced by 14.18 GWh for Sang’oro HPP between 2012 and 2018. Understanding climate change trends within Sondu Miriu River basin should guide the planning for hydropower development projects.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76068133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phenology and mechanisms of the early upwelling formation in the southern coast of Senegal","authors":"Wade Malick, Thiam Mamadou, Diba Ibrahima, Diop Bouya","doi":"10.5897/ajest2021.3071","DOIUrl":"https://doi.org/10.5897/ajest2021.3071","url":null,"abstract":"Mechanisms of the interannual variability of upwelling onset dates on the Petite-Cote of Senegal are investigated using daily NEMO model data outputs and NOAA ocean surface temperature observations (OISST). We first determined the phenology (onset dates, end dates, duration and occupied area of the upwelling) over the Petite-Côte located in south of the Senegalese coast. Our results show that upwelling in the Petite-Côte starts on average on 03-December (with a standard deviation of 13 days) and ends on average on 13-June (with a standard deviation of 11 days). Upwelling lasts, on average, 6 months in the region. The maximum upwelling intensity is noted on 15-May and the maximum occupied area exhibits a February-May plateau. We then performed a composite analysis based on the earliness of the upwelling setup dates to understand the mechanisms involved. Our results show that for the earliest upwelling years, we note a strengthening of the vertical velocities 3 weeks before the onset of the upwelling but we note especially an abnormal intensification of the coastal jet. The latter seems to be the initiator of the early onset of the upwelling in the region. These reinforcements are associated with a significant decrease in surface temperature (SST) and an intensification of northerly trade winds. of upwelling for all atmospheric and oceanic variables to better diagnose the behavior of the parameters for early upwelling years. Finally, for the composite analysis of the different variables, we apply a lanczos filter to the data at intra-seasonal timescale to remove frequencies greater than 90 days.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73816591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The environmental impact of landfill fires and their contaminant plumes at the Chunga landfill site, Lusaka, Zambia","authors":"Milimo Muleya, Graham Hinchliffe, M. Petterson","doi":"10.5897/ajest2021.3008","DOIUrl":"https://doi.org/10.5897/ajest2021.3008","url":null,"abstract":"The management of solid waste is recognised as a challenging activity with respect to the environment, particularly within rapidly growing urban centres in Lower Income Countries. This paper examines the issue of landfill-waste-generated fires and resultant pollution plumes sourced within the Chunga Landfill Site, Lusaka, Zambia. The authors present the results of a geospatial analysis research programme to map and assess risks posed by landfill combustion. The project identified fires and their plumes in the period 2013 to 2019. Pollution plumes are predominantly oriented East to West but also form plumes blowing towards the South West and North West. The area impacted by landfill plumes increased from 34 ha in 2013 to 133 ha in 2019. There is significant existential and potential human-exposure to these plumes. An estimated 5000 residents live within the areas affected by landfill-combustion-plumes. The authors suggest the following framework for landfill management to be adopted: (1) for waste to be increasingly sorted and segregated with different disposal options developed for different types of waste; ( 2) for methane and gas evacuation pipes to be inserted into the Chunga Site in a systematic rectilinear manner which allows for its safe dispersal: alternately collect the gases as usable biogas; (3) rapid extinguishing of any fires; (4) weekly monitoring of the landfill site by UAV and on-theground inspections; (5) active weekly monitoring of air quality; (6) develop a communication strategy that aims to engage local residents and other stakeholders concerning Chunga Landfill waste management; (7) the further drafting of medium-long term waste management policy in Lusaka that takes account of the rapid population growth and increasing landfill requirements.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89619639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the deposit conditions of sedimentary series of fluvio-lacustrine and aeolian origin in the Djourab desert, in Northern Chad","authors":"A. Moussa, Nour Abdallah Mahamat, H. Abderamane, H. Mackaye, A. Likius, M. Schuster, P. Duringer, J. Ghienne, P. Vignaud","doi":"10.5897/ajest2021.3042","DOIUrl":"https://doi.org/10.5897/ajest2021.3042","url":null,"abstract":"","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87343417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatio-temporal dynamics of land use on the expansion of coffee agroforestry systems in Cameroons production basins","authors":"Kuete Fogang Marcien, Louise Avana Tientcheu Marie, Tankou Christopher, Ndo Eunice","doi":"10.5897/ajest2021.3073","DOIUrl":"https://doi.org/10.5897/ajest2021.3073","url":null,"abstract":"","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"97 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85387725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving future temperature projections with bias correction methods in Lake of Guiers/Senegal","authors":"B. S. Alioune","doi":"10.5897/ajest2021.3031","DOIUrl":"https://doi.org/10.5897/ajest2021.3031","url":null,"abstract":"Climate models are generally used to evaluate the climate change impacts. However, they have important biases at the regional or local scales. This study evaluates the future temperature projections in Lake of Guiers/Senegal. For this, the daily maximum and minimum temperature from the ensemble mean of five (5) Coordinated Regional climate Downscaling Experiment (CORDEX) regional climate models (RCMs) under the greenhouse gas scenarios RCP4.5 and RCP8.5 and three (3) bias correction methods (Linear scaling, variance scaling and quantile mapping methods) were used. The performance of raw ensemble mean of the models was first evaluated against the WFDEI data. The results show that this latter exhibits some limitations to reproduce the minimum and the maximum temperature at the Lake scale. In order to make temperature data more accurate, the three bias correction methods were used. Results show that bias correction methods improve well the simulated minimum and maximum temperature. The future temperature projections show an increase of temperature which are faster in bias-corrected data. From the results it is indicated that it is necessary to implement appropriate adaptation measures to address these climate changes.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81844778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of effective microorganisms to enhance cost-effective biogas purification at the household level","authors":"Minza Selele, M. S. Mgana, E. S. Mbuligwe","doi":"10.5897/ajest2020.2935","DOIUrl":"https://doi.org/10.5897/ajest2020.2935","url":null,"abstract":"This study investigated the use of effective microorganisms (EM) to enhance cost-effective biogas purification at household-level application. It involved experimental setups for biogas purification in two different runs: 4 L activated EM and 1 L dormant EM by bubbling biogas through EM purification units. Biogas composition was analyzed using an industry-standard biogas analyzer. The results indicated that EM has the potential for biogas purification through a biological process, to remove H2S and CO2 by involving photosynthetic bacteria (Rhodopseudomonas palustris) in the presence of light. The raw biogas average composition was 62.2% CH4, 37.4% CO2 and 1359.3 ppm H2S. The 4L activated EM batch solution purified the raw biogas to 80.2% CH4, 19.5% CO2 and 786.1 ppm H2S. The corresponding purification efficiencies are 60% for CO2 and 49% for H2S. Purified biogas could be used by the household to cook for 1.82 h (85%) while raw biogas could cover only 55%. The designed biogas purification system can cost only Tshs 91,010/= and purify about 15,000 L of biogas at EM cost of Tshs 9,100/month.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85050892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the influence of precipitation patterns on wetland sizes in South-Eastern Zimbabwe","authors":"F. Makarati, T. Ruhiiga, L. Palamuleni","doi":"10.5897/AJEST2020.2862","DOIUrl":"https://doi.org/10.5897/AJEST2020.2862","url":null,"abstract":"In this paper, the hypothesis that rainfall variability has an impact on wetland loss is tested. There is limited research in Zimbabwe that recognises the influence of rainfall variability on wetland loss. The purpose of this research is to determine the influence of rainfall variability on wetland size over time. Topographical maps, for the period 1972 to 2008, provided data on wetland locations and their changes in size with time. Rainfall data for Masvingo province for the 1980 to 2015 period was obtained from the Meteorological Services Department (MSD) of Zimbabwe. Statistical analysis shows that there is no relationship between rainfall variability and wetland loss. It can be concluded that there is no relationship between rainfall variability and wetland loss therefore. The research findings show that the rates of change in wetland size differ from one wetland to another. The implications on wetland management are that interventions should largely address human causal factors of wetland loss than rainfall variability. Therefore, it is vital to devise a wetland rehabilitation plan that enables management of water from the rivers and wetlands that the communities depend on. \u0000 \u0000   \u0000 \u0000 Key words: Climate change, rainfall variability, standard precipitation index (SPI), wetland rehabilitation, Zimbabwe.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"10 1","pages":"439-450"},"PeriodicalIF":0.0,"publicationDate":"2021-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83508450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Food waste produced lactic acid for pathogen inactivation, urea stabilization and odor control in feces","authors":"Getaneh Zerihun, N. Agizew, D. Adey, G. Nancy","doi":"10.5897/ajest2021.3056","DOIUrl":"https://doi.org/10.5897/ajest2021.3056","url":null,"abstract":"","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83243458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatio-temporal distribution of Naididae tubificids species and bio-evaluation of the quality of some surface water bodies of Yaound, Cameroon","authors":"Y. D. A. Moussima, G. Ajeagah, Bilong Charles Félix Bilong","doi":"10.5897/ajest2021.3049","DOIUrl":"https://doi.org/10.5897/ajest2021.3049","url":null,"abstract":"","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"113 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90741038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}