Nimusiima Alex, F. Nalwanga, I. Mugume, B. Ogwang, P. Waswa
Weather and climate issues have become increasingly recognized among the global challenges especially in the era of climate change. Kampala city has faced a number of flooding events in the past that have led to serious damages in many low lying areas of the city. A study was conducted in one of the flood prone areas in Kampala city to understand the community perspectives on flood occurrence and weather forecasting in the area. The main objective was to understand community perceptions on flood occurrence as well as use of weather information for early warning. Data was collected from 400 respondents using a structured questionnaire as well as focused group discussions. Results from the survey revealed that 99.8% of the respondents reported rainfall intensities to have increased in the last 5 years and as a result, 96% of these respondents stated floods as the main climate risk in the area. The most common impacts of floods in the community included loss of property, lack of safe and clean water and disease outbreaks among others. In response to floods, the community identified use of raised tables or stands and use of stones in the compound as the main coping mechanisms employed in the community. In terms of weather alerts, only 22% of respondents reported receiving the weather alerts issued by the Uganda National Meteorological Authority (UNMA). Of those who receive the alerts, 91% hear the information mainly on television. Therefore, the study proposes strengthening of collaboration between UNMA and the local leaders through the Kampala Capital City Authority (KCCA) for provision of earlier weather forecasts that help reduce the negative flood impacts among communities. Key words: Weather alerts, flood forecasting, changing climate and community perspectives.
{"title":"A community perspective of flood occurrence and weather forecasting over Kampala City","authors":"Nimusiima Alex, F. Nalwanga, I. Mugume, B. Ogwang, P. Waswa","doi":"10.5897/AJEST2021.3007","DOIUrl":"https://doi.org/10.5897/AJEST2021.3007","url":null,"abstract":"Weather and climate issues have become increasingly recognized among the global challenges especially in the era of climate change. Kampala city has faced a number of flooding events in the past that have led to serious damages in many low lying areas of the city. A study was conducted in one of the flood prone areas in Kampala city to understand the community perspectives on flood occurrence and weather forecasting in the area. The main objective was to understand community perceptions on flood occurrence as well as use of weather information for early warning. Data was collected from 400 respondents using a structured questionnaire as well as focused group discussions. Results from the survey revealed that 99.8% of the respondents reported rainfall intensities to have increased in the last 5 years and as a result, 96% of these respondents stated floods as the main climate risk in the area. The most common impacts of floods in the community included loss of property, lack of safe and clean water and disease outbreaks among others. In response to floods, the community identified use of raised tables or stands and use of stones in the compound as the main coping mechanisms employed in the community. In terms of weather alerts, only 22% of respondents reported receiving the weather alerts issued by the Uganda National Meteorological Authority (UNMA). Of those who receive the alerts, 91% hear the information mainly on television. Therefore, the study proposes strengthening of collaboration between UNMA and the local leaders through the Kampala Capital City Authority (KCCA) for provision of earlier weather forecasts that help reduce the negative flood impacts among communities. \u0000 \u0000 \u0000 \u0000 Key words: Weather alerts, flood forecasting, changing climate and community perspectives.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89932071","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}
Freshwater ecosystems are the major source of water, being used for domestic, agricultural and industrial purposes. Water bodies are subjected to anthropogenic activities leading to degradation of the water quality. The aim of this study is to assess the health status of Isiokpo River. Aquatic insects were sampled from March to August 2017. Physico-chemical parameters were examined using standard laboratory procedures. A total of 21 taxa comprising of 543 individual insects were recovered. Stations 1, 2 and 3 recorded 53.41, 21.36 and 25.23% of the insect population respectively. A total of six Ephemeroptera, Plecoptera and Trichoptera (EPT) species were recorded in the study. The %EPT was 28.57, 33.33 and 30.77% in station 1, 2 and 3 respectively. There were significant differences in the distribution of dissolved oxygen, phosphate, nitrates transparency, flow velocity, and total dissolved solids across the various stations (p<0.05). The reduced level of dissolved oxygen in station 3 as well the dominance of Chironomus sp. are indications of the impact of anthropogenic activities. The study showed that the Isiokpo River is relatively unhealthy. Key words: Aquatic insects, Biomonitoring, Freshwater, Ephemeroptera, Plecoptera, Trichoptera, Water quality.
{"title":"Ecological status of a tropical river in Niger delta area of Nigeria, using aquatic insects","authors":"Enajerho Manuel, T. Gbarakoro","doi":"10.5897/AJEST2020.2918","DOIUrl":"https://doi.org/10.5897/AJEST2020.2918","url":null,"abstract":"Freshwater ecosystems are the major source of water, being used for domestic, agricultural and industrial purposes. Water bodies are subjected to anthropogenic activities leading to degradation of the water quality. The aim of this study is to assess the health status of Isiokpo River. Aquatic insects were sampled from March to August 2017. Physico-chemical parameters were examined using standard laboratory procedures. A total of 21 taxa comprising of 543 individual insects were recovered. Stations 1, 2 and 3 recorded 53.41, 21.36 and 25.23% of the insect population respectively. A total of six Ephemeroptera, Plecoptera and Trichoptera (EPT) species were recorded in the study. The %EPT was 28.57, 33.33 and 30.77% in station 1, 2 and 3 respectively. There were significant differences in the distribution of dissolved oxygen, phosphate, nitrates transparency, flow velocity, and total dissolved solids across the various stations (p<0.05). The reduced level of dissolved oxygen in station 3 as well the dominance of Chironomus sp. are indications of the impact of anthropogenic activities. The study showed that the Isiokpo River is relatively unhealthy. \u0000 \u0000 \u0000 \u0000 Key words: Aquatic insects, Biomonitoring, Freshwater, Ephemeroptera, Plecoptera, Trichoptera, Water quality.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"125 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85276751","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}
Research on the impacts of mining on the environment was conducted on nine purposive selected mining sites in Kamtonga and Mkuki, Taita Taveta County, Kenya. The FOLCHI method was adopted to quantify the environmental impact of mining activities in gemstone mining sites. The affected environment surrounding the pits was broken down into three components such as Topography, Vegetation and Air. The effect of the three components impacting factors, both directly and indirectly, from the mining activities was then calculated for each Environmental Component and computed averages (magnitude) presented in table format. The findings showed that mining activities contributed to environmental and landscape changes, leading to loss of indigenous-trees, shrubs, grassland, forests, natural ecosystems and agricultural and grazing land. Mining activities contributed to air pollution. Even with the existence of environmental regulations and policies, the environment is still abused in Kenya, as a result, the country has lost considerable amount of forest cover due to mining activities. Government and non-governmental organizations should advocate for afforestation, re-afforestation and restoration of forests. Environmental Impact Assessment and Environmental Audit should be conducted in line with mining regulations in Environmental Management and Coordination act 1999 (amended 2019) in Kenya. Key words: Mining activities, environmental elements, waste piles, sustainable livelihoods, air pollution, forest restoration.
{"title":"Impact of mining on environment: A case study of Taita Taveta County, Kenya","authors":"I. Mwakesi, R. Wahome, D. Ichang'i","doi":"10.5897/AJEST2020.2926","DOIUrl":"https://doi.org/10.5897/AJEST2020.2926","url":null,"abstract":"Research on the impacts of mining on the environment was conducted on nine purposive selected mining sites in Kamtonga and Mkuki, Taita Taveta County, Kenya. The FOLCHI method was adopted to quantify the environmental impact of mining activities in gemstone mining sites. The affected environment surrounding the pits was broken down into three components such as Topography, Vegetation and Air. The effect of the three components impacting factors, both directly and indirectly, from the mining activities was then calculated for each Environmental Component and computed averages (magnitude) presented in table format. The findings showed that mining activities contributed to environmental and landscape changes, leading to loss of indigenous-trees, shrubs, grassland, forests, natural ecosystems and agricultural and grazing land. Mining activities contributed to air pollution. Even with the existence of environmental regulations and policies, the environment is still abused in Kenya, as a result, the country has lost considerable amount of forest cover due to mining activities. Government and non-governmental organizations should advocate for afforestation, re-afforestation and restoration of forests. Environmental Impact Assessment and Environmental Audit should be conducted in line with mining regulations in Environmental Management and Coordination act 1999 (amended 2019) in Kenya. \u0000 \u0000 \u0000 \u0000 Key words: Mining activities, environmental elements, waste piles, sustainable livelihoods, air pollution, forest restoration.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74901039","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}
Environmental pollution leads to poor health and has been a worrisome experience to humanity for the past few decades. This research was conducted to determine the pollution potential of landfill leachates (LFL) in Sub-Saharan Africa, using Ibadan as case study. Survey of landfills in the metropolis was undertaken; the two major active unlined landfills (Ajakanga and Awotan), were considered for this study. During sampling, eighteen parameters of interest were analyzed. The leachate pollution indices (LPI) of each landfill were calculated. The LPI of Awotan landfill is 17.55 while that of Ajakanga is 15.67. With the exceedances of the 7.378 standard LPI value, all landfills in the metropolis is recommended to be closed down in line with international best practices and new sanitary landfills set up in their stead. Based on the sub-LPI values obtained, biological treatment would be the most viable treatment option for the LFL produced. The findings from this study are applicable in landfill management in other countries within the African sub-region; thereby contributing to the attainment of Sustainable Development Goals (SDGs). Key words: Leachate pollution index, landfill, sustainable development goals, Ibadan, Nigeria, assessment.
{"title":"Assessment of leachate contamination potential of landfills in Ibadan, Nigeria","authors":"S. Adesogan, Baldwin O. Omonigho","doi":"10.5897/AJEST2021.3009","DOIUrl":"https://doi.org/10.5897/AJEST2021.3009","url":null,"abstract":"Environmental pollution leads to poor health and has been a worrisome experience to humanity for the past few decades. This research was conducted to determine the pollution potential of landfill leachates (LFL) in Sub-Saharan Africa, using Ibadan as case study. Survey of landfills in the metropolis was undertaken; the two major active unlined landfills (Ajakanga and Awotan), were considered for this study. During sampling, eighteen parameters of interest were analyzed. The leachate pollution indices (LPI) of each landfill were calculated. The LPI of Awotan landfill is 17.55 while that of Ajakanga is 15.67. With the exceedances of the 7.378 standard LPI value, all landfills in the metropolis is recommended to be closed down in line with international best practices and new sanitary landfills set up in their stead. Based on the sub-LPI values obtained, biological treatment would be the most viable treatment option for the LFL produced. The findings from this study are applicable in landfill management in other countries within the African sub-region; thereby contributing to the attainment of Sustainable Development Goals (SDGs). \u0000 \u0000 \u0000 \u0000 Key words: Leachate pollution index, landfill, sustainable development goals, Ibadan, Nigeria, assessment.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89318471","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}
Mustapha Ouhsassi, E. Khay, A. E. Laghdach, F. Abdelouahab, Abdeltif El Ouahrani, M. Idaomar, J. Abrini
Cyanobacteria thrive in eutrophic freshwaters and impose a serious problem for the management of water bodies. Some Cyanobacteria species impose even a risk for public health due to the production of intracellular toxins. This study is a qualitative approach to determine the degree of toxicity and the toxicological aspect of cyanotoxins in order to setup a monitoring program for cyanobacteria blooms and the management of cyanotoxins thriving in three water bodies in Northern Morocco. Water samples were collected from three major water reservoirs/dams near the city of Tetouan (SMIR, BELMEHDI and NAKHLA). These water samples were screened for possible Cyanobacteria using specific culture media (BG13 & Z8). Three cyanobacteria species (Microcystis aeruginosa, Pseudanabaena galeata and Oscillatoria tenuis) were isolated, purified and lyophilized. Using gas chromatography coupled with mass spectrometry, nine types of microcystins were characterized namely: (MC-LR); (MC-YR); (MC-LA); (MC-FR); (MC-RF), [Mser7]MC-LR; [Dha7]MC-LR; MC-YAba; and [Mser7]MC-YR. Our results strongly recommend and urge different stakeholders to consider the various health risks potentially generated by these toxins during water use and management. In addition, this study is a contribution to raise awareness of the toxicological aspect of the cyanobacteria inhabiting the water bodies of Northern Morocco. Key words: Blue algae, gas chromatography coupled to mass spectrum, bio-toxins, water dam.
{"title":"Characterization of cyanobacteria microcystins (cyanotoxins) blooming in the Dams of \u0000Northern Morocco","authors":"Mustapha Ouhsassi, E. Khay, A. E. Laghdach, F. Abdelouahab, Abdeltif El Ouahrani, M. Idaomar, J. Abrini","doi":"10.5897/AJEST2020.2967","DOIUrl":"https://doi.org/10.5897/AJEST2020.2967","url":null,"abstract":"Cyanobacteria thrive in eutrophic freshwaters and impose a serious problem for the management of water bodies. Some Cyanobacteria species impose even a risk for public health due to the production of intracellular toxins. This study is a qualitative approach to determine the degree of toxicity and the toxicological aspect of cyanotoxins in order to setup a monitoring program for cyanobacteria blooms and the management of cyanotoxins thriving in three water bodies in Northern Morocco. Water samples were collected from three major water reservoirs/dams near the city of Tetouan (SMIR, BELMEHDI and NAKHLA). These water samples were screened for possible Cyanobacteria using specific culture media (BG13 & Z8). Three cyanobacteria species (Microcystis aeruginosa, Pseudanabaena galeata and Oscillatoria tenuis) were isolated, purified and lyophilized. Using gas chromatography coupled with mass spectrometry, nine types of microcystins were characterized namely: (MC-LR); (MC-YR); (MC-LA); (MC-FR); (MC-RF), [Mser7]MC-LR; [Dha7]MC-LR; MC-YAba; and [Mser7]MC-YR. Our results strongly recommend and urge different stakeholders to consider the various health risks potentially generated by these toxins during water use and management. In addition, this study is a contribution to raise awareness of the toxicological aspect of the cyanobacteria inhabiting the water bodies of Northern Morocco. \u0000 \u0000 \u0000 \u0000 Key words: Blue algae, gas chromatography coupled to mass spectrum, bio-toxins, water dam.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"38 1","pages":"124-141"},"PeriodicalIF":0.0,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84915142","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}
Nafiou Egbéola Chitou, W. Chouti, Jacques Kouazounde, D. Mama, Arthur R. Cakpo
Alibori River located in northwestern Benin is subject to contamination by trace metal elements (TME: Zn, Cu, Pb, Cd) due to the use of agricultural inputs in its vicinity. This study focuses on the speciation of TME elements in the sediments of this river. The sediments were sampled during the rainy and dry seasons, dried, crushed and then sieved. The sediments were then mineralized and subjected to sequential fractionation. The total extraction and sequential extractions were analyzed using a spectrophotometer UV. The sediments of Alibori River had an acid pH and were contaminated by TME during the dry season. The zinc and copper had an affinity with the different fractions with a high proportion in the fractions F1 and F2 during the rainy season and a high proportion in the F5 fraction during the dry season. The lead and cadmium had an affinity with the F5 fraction during the rainy season, and the F3 and F4 fractions during the dry season. The calculated contamination index, individual contamination factor and risk assessment code (RAC) demonstrated that the river presented a potential risk of water contamination. The aforementioned parameters also showed that the river induced risk of bioavailability ranging from medium to very high for organisms. The TMEs found in the sediments of the Alibori River were linked to the exchangeable and acid-soluble fractions which made them more mobile and bioavailable to organisms. Key words: Speciation, Alibori River, trace metal elements (TME), bioavailability, fraction.
{"title":"Speciation of trace metal elements in sediments of Alibori River, North-West of Benin","authors":"Nafiou Egbéola Chitou, W. Chouti, Jacques Kouazounde, D. Mama, Arthur R. Cakpo","doi":"10.5897/AJEST2020.2954","DOIUrl":"https://doi.org/10.5897/AJEST2020.2954","url":null,"abstract":"Alibori River located in northwestern Benin is subject to contamination by trace metal elements (TME: Zn, Cu, Pb, Cd) due to the use of agricultural inputs in its vicinity. This study focuses on the speciation of TME elements in the sediments of this river. The sediments were sampled during the rainy and dry seasons, dried, crushed and then sieved. The sediments were then mineralized and subjected to sequential fractionation. The total extraction and sequential extractions were analyzed using a spectrophotometer UV. The sediments of Alibori River had an acid pH and were contaminated by TME during the dry season. The zinc and copper had an affinity with the different fractions with a high proportion in the fractions F1 and F2 during the rainy season and a high proportion in the F5 fraction during the dry season. The lead and cadmium had an affinity with the F5 fraction during the rainy season, and the F3 and F4 fractions during the dry season. The calculated contamination index, individual contamination factor and risk assessment code (RAC) demonstrated that the river presented a potential risk of water contamination. The aforementioned parameters also showed that the river induced risk of bioavailability ranging from medium to very high for organisms. The TMEs found in the sediments of the Alibori River were linked to the exchangeable and acid-soluble fractions which made them more mobile and bioavailable to organisms. \u0000 \u0000 \u0000 \u0000 Key words: Speciation, Alibori River, trace metal elements (TME), bioavailability, fraction.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"1 1","pages":"142-157"},"PeriodicalIF":0.0,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89319764","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}
A. J. Osarokaka, S. Nzeako, H. Imafidor, U. Living-Jamala
Crude oil spill destroys biodiversity and adversely impacts the physicochemical characteristics of the terrestrial and aquatic environments. The population characteristics of soil nematodes can serve as indicators of alterations in the terrestrial environment. To determine the effects of crude oil spillage on the soil nematode fauna status; a study was carried out at an impacted area in Gokana Local Government Area of Rivers State, Nigeria. 60 soil samples were randomly collected vertically (30 from the unpolluted sites and 30 from the polluted sites) at designated depths of 0-5 cm, 6-10 cm and 11-15 cm with the aid of a calibrated soil corer. Soil samples were taken to the laboratory for nematode extraction using the Baermann’s extraction technique and the sieving method. Physiochemical parameters of the soil samples were determined using standard laboratory techniques. A total of 340 nematodes (from 11 genera) were recovered in the soil samples comprising; 169 (49.7%) nematodes from polluted sites and 171 (50.3%) nematodes from the unpolluted sites. There was slight variability in nematode species diversity, richness and abundance in the polluted and unpolluted sites (p>0.05). Crude oil pollution influenced soil nematodes community composition while anthropological interferences such as farming influenced the successional trend of which was reflected in the maturity index values obtained from the study. Key words: Crude oil, soil nematodes, biodiversity, polluted sites and maturity index.
{"title":"Soil nematodes status of crude oil polluted sites in Bodo community, Gokana Local Government Area, Rivers State, Nigeria","authors":"A. J. Osarokaka, S. Nzeako, H. Imafidor, U. Living-Jamala","doi":"10.5897/AJEST2020.2864","DOIUrl":"https://doi.org/10.5897/AJEST2020.2864","url":null,"abstract":"Crude oil spill destroys biodiversity and adversely impacts the physicochemical characteristics of the terrestrial and aquatic environments. The population characteristics of soil nematodes can serve as indicators of alterations in the terrestrial environment. To determine the effects of crude oil spillage on the soil nematode fauna status; a study was carried out at an impacted area in Gokana Local Government Area of Rivers State, Nigeria. 60 soil samples were randomly collected vertically (30 from the unpolluted sites and 30 from the polluted sites) at designated depths of 0-5 cm, 6-10 cm and 11-15 cm with the aid of a calibrated soil corer. Soil samples were taken to the laboratory for nematode extraction using the Baermann’s extraction technique and the sieving method. Physiochemical parameters of the soil samples were determined using standard laboratory techniques. A total of 340 nematodes (from 11 genera) were recovered in the soil samples comprising; 169 (49.7%) nematodes from polluted sites and 171 (50.3%) nematodes from the unpolluted sites. There was slight variability in nematode species diversity, richness and abundance in the polluted and unpolluted sites (p>0.05). Crude oil pollution influenced soil nematodes community composition while anthropological interferences such as farming influenced the successional trend of which was reflected in the maturity index values obtained from the study. Key words: Crude oil, soil nematodes, biodiversity, polluted sites and maturity index.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73353263","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}
F. Babalola, A. O. Adelopo, Boluwatito M. Aiyepola, A. T. Nubi
The design of a sustainable waste management system is pivoted on the ability to generate and compute real-time operational data for a strategic developmental decision plan. The real-time waste data generated at the University of Lagos Campus waste management system was used to develop a mathematical model with three operational indicators, namely, Total Cost Indicator (TCI), to show the overall daily cost for managing one metric ton of mixed municipal waste in the system from collection to final disposal, Lost Revenue Indicator (LRI), to show revenue loss for each metric ton of residual waste landfilled, and Material Recovery Indicator (MRI), to show the fraction of recyclable materials recovered from collected mixed waste. All three indicators were calculated at different recyclable materials recovery efficiencies to determine the cost implication on the system’s operational parameters. The model revealed that the present municipal solid waste (MSW) system operates at a recyclables recovery efficiency rate of approximately 3% but can be increased at optimum capacity to 18%. This performance improvement will result in a cost reduction of $0.32/ton when daily sorters’ capacity, material revenue potential and result-based financing recycling operations are determined using this model as a strategic management planning tool. The model provides an adaptable framework for the development of MSW management decision plans for cities in a developing nation. Key words: Material recovery, municipal solid waste, cost minimization model.
{"title":"Cost minimization and operation optimization model for strategic waste management decision plans: A case study","authors":"F. Babalola, A. O. Adelopo, Boluwatito M. Aiyepola, A. T. Nubi","doi":"10.5897/AJEST2020.2908","DOIUrl":"https://doi.org/10.5897/AJEST2020.2908","url":null,"abstract":"The design of a sustainable waste management system is pivoted on the ability to generate and compute real-time operational data for a strategic developmental decision plan. The real-time waste data generated at the University of Lagos Campus waste management system was used to develop a mathematical model with three operational indicators, namely, Total Cost Indicator (TCI), to show the overall daily cost for managing one metric ton of mixed municipal waste in the system from collection to final disposal, Lost Revenue Indicator (LRI), to show revenue loss for each metric ton of residual waste landfilled, and Material Recovery Indicator (MRI), to show the fraction of recyclable materials recovered from collected mixed waste. All three indicators were calculated at different recyclable materials recovery efficiencies to determine the cost implication on the system’s operational parameters. The model revealed that the present municipal solid waste (MSW) system operates at a recyclables recovery efficiency rate of approximately 3% but can be increased at optimum capacity to 18%. This performance improvement will result in a cost reduction of $0.32/ton when daily sorters’ capacity, material revenue potential and result-based financing recycling operations are determined using this model as a strategic management planning tool. The model provides an adaptable framework for the development of MSW management decision plans for cities in a developing nation. \u0000 \u0000 \u0000 \u0000 Key words: Material recovery, municipal solid waste, cost minimization model.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"2004 1","pages":"98-108"},"PeriodicalIF":0.0,"publicationDate":"2021-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83026787","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}
R. Adelagun, O. Ushie, A. Kamba, E. Aikhoje, O. G. Egah
Kinetics of phosphate adsorption by Ca/Cr layered double hydroxide (LDH) in a batch reactor was investigated in this study. The kinetic experiments indicated that the sorption of phosphate from the synthetic feed solution by the synthesised LDH was very fast, with over 98% removal being achieved within 5 min of contact. Kinetic modeling of the sorption process to different kinetic models (pseudo first order, pseudo second order, Elovich and intraparticle diffusion) showed that the pseudo-second order model best described the process. Studies of effect of hydrochemistry on the sorption process such as initial solution pH, ionic strength and organic load contamination interference, indicated nominal effect on the amount of phosphate removed by the LDH. Overall, the study indicated that chemisorption and precipitation are active contributory mechanisms to the sorption of phosphate by Ca/Cr LDH from solution. Key words: Adsorption kinetics, chemisorption, layered double hydroxide, phosphate removal, precipitation.
{"title":"Kinetics of phosphate adsorption by Ca/Cr layered double hydroxide","authors":"R. Adelagun, O. Ushie, A. Kamba, E. Aikhoje, O. G. Egah","doi":"10.5897/AJEST2018.2594","DOIUrl":"https://doi.org/10.5897/AJEST2018.2594","url":null,"abstract":"Kinetics of phosphate adsorption by Ca/Cr layered double hydroxide (LDH) in a batch reactor was investigated in this study. The kinetic experiments indicated that the sorption of phosphate from the synthetic feed solution by the synthesised LDH was very fast, with over 98% removal being achieved within 5 min of contact. Kinetic modeling of the sorption process to different kinetic models (pseudo first order, pseudo second order, Elovich and intraparticle diffusion) showed that the pseudo-second order model best described the process. Studies of effect of hydrochemistry on the sorption process such as initial solution pH, ionic strength and organic load contamination interference, indicated nominal effect on the amount of phosphate removed by the LDH. Overall, the study indicated that chemisorption and precipitation are active contributory mechanisms to the sorption of phosphate by Ca/Cr LDH from solution. \u0000 \u0000 \u0000 \u0000 Key words: Adsorption kinetics, chemisorption, layered double hydroxide, phosphate removal, precipitation.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"295 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79125959","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}
S. Diatta, Adama Thiandoum, M. Mbaye, A. Sarr, M. Camara
The climate risk concept is crucial for agricultural production in vulnerable regions. In this work the climate conditions that influence the climate risk for rice crop in Casamance are presented. The future occurrence of drought and extreme precipitation conditions in the most critical phases of the rice plant evolution has been evaluated. Regional climate models (RCMs) outputs projections from CORDEX under two scenarios emissions (RCP4.5 and RCP8.5) in the mid of the twenty-first century were used to highlight the change in four extreme climate indices in the germination (JJ) and the flowering (Oct) stages of the rice plant in the Casamance region. The results suggest a potential risk in rice crop yield losses in the germination phase due to persistent drought conditions in the mid-twenty-first century namely in the low Casamance and the Middle Casamance; also increasing future occurrence of heavy rainfall may cause juvenile rice plant submersion that could contribute to rice production reduction. The flowering stage will present less climate risk situation in the future; the distribution of drought conditions seems to follow the normal north-south distribution; however hazardous extreme conditions could be expected in the future. There is a need to better plan agronomic and water management policies. Key words: Regional climate model, future projection, extreme precipitation, climate risk, rice crop, Casamance.
{"title":"Projected climate risks for rice crops in Casamance, Southern Senegal","authors":"S. Diatta, Adama Thiandoum, M. Mbaye, A. Sarr, M. Camara","doi":"10.5897/AJEST2020.2963","DOIUrl":"https://doi.org/10.5897/AJEST2020.2963","url":null,"abstract":"The climate risk concept is crucial for agricultural production in vulnerable regions. In this work the climate conditions that influence the climate risk for rice crop in Casamance are presented. The future occurrence of drought and extreme precipitation conditions in the most critical phases of the rice plant evolution has been evaluated. Regional climate models (RCMs) outputs projections from CORDEX under two scenarios emissions (RCP4.5 and RCP8.5) in the mid of the twenty-first century were used to highlight the change in four extreme climate indices in the germination (JJ) and the flowering (Oct) stages of the rice plant in the Casamance region. The results suggest a potential risk in rice crop yield losses in the germination phase due to persistent drought conditions in the mid-twenty-first century namely in the low Casamance and the Middle Casamance; also increasing future occurrence of heavy rainfall may cause juvenile rice plant submersion that could contribute to rice production reduction. The flowering stage will present less climate risk situation in the future; the distribution of drought conditions seems to follow the normal north-south distribution; however hazardous extreme conditions could be expected in the future. There is a need to better plan agronomic and water management policies. \u0000 \u0000 \u0000 \u0000 Key words: Regional climate model, future projection, extreme precipitation, climate risk, rice crop, Casamance.","PeriodicalId":7483,"journal":{"name":"African Journal of Environmental Science and Technology","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73143732","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}
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