Environmental Science
Permanent URI for this collection
Browse
Recent Submissions
Item Impacts of Climate Variability on Crop Production and Farmers’ Adaptation Strategies in Bassona Worana Woreda, North Shoa Zone, Ethiopia(Addis Ababa University, 2014-05) Asnake Atakure; Belay SimaneClimate change is expected to have serious environmental, economic and social impacts in Ethiopia. The extent of which these impacts depends on the level of adaptive capacity, particularly among rural farmers whose livelihood depends on rain-fed agriculture as a primary source of food production. The study analyzed the impact of climate change on crop production and farmers’ adaptation strategies to climate change in Bassona Worana Woreda of North Shoa Zone, Amhara Regional State, Ethiopia. This study was based on both secondary and primary data by conducting a comprehensive assessment of temperature and rainfall variations and the impacts on the most commonly grown crops. Farmers’ adaptation strategies were examined based on a questionnaire designed to investigate farmers’ ability to adapt to climate change. Mann-Kendall trend tests were used to examine trends of temperature and rainfall. Whereas Correlation and regression tests were carried out against dependent variables (teff, wheat, barley and sorghum) in order to examine the relationship between climate variability and crops. The study was also analyzed farmers’ perception and adaptation responses to climate change. The finding of the study shows that there is significant increasing trend in the amount of annual rainfall (4.857mm/year). However, there is a significant decreasing trend of rainfall during Belg season (-2.88mm/year). Mean annual temperature and mean annual maximum temperature shows a significant increasing trend while the mean annual minimum temperature is increasing but not significant. Significant negative correlations were observed between Belg rainfall and crop production and negative correlations between most of annual, seasonal and monthly temperatures and crop production. The survey revealed that a significant number of farmers believed that temperatures were increasing and precipitation was declining. Farmers’ perceptions on whether the climate was changing were greatly influenced by incidences of drought and changes in the seasonal timing of rainfall. Farmers practiced soil and water conservation and planting trees as a major adaptation options. The findings suggest that Ethiopia should begin to plan for climate contingencies at grassroots level. Augmenting the existing adaptation skill should be given a high priority and actions that make agriculture sectors more immune to climate should be taken in advance.Item Heavy Metal Accumulation by Oyster Mushroom (Pleurotus Ostreatus) Cultivated on Agricultural Land Irrigated by Akaki River(Addis Ababa University, 2015-10) Kuma Bedada; Rajeev PandeyThe accumulation of heavy metals in agricultural soils is of increasing concern due to the food safety issue and potential health risks. Sources of these elements in soils mainly include industries and human activities. International and national regulations on food quality have lowered the maximum permissible levels of toxic metals in the food items due to an increased awareness of the risk these metals pose to food chain contamination. Remediation of soil contaminated with heavy metals has received considerable attention in recent years. So, looking to the severity of problem due to heavy metals contamination and there need of remediation, the present study was conducted on experimental site soil situated near Aba Samuel dam build on Akaki river followed by control. The study was conducted on the effects of heavy metal contamination accumulated in selected commonly available edible mushroom (Pleurotus ostreatus) along with bioaccumulation potential of selected mushroom species for heavy metals (Cd, Cr, Cu, Pb, Ni & Zn). The effects of waste water on selected site soil samples were conducted by means of first and second cultivation of mushroom. Positive affect of mushroom cultivation were found on waste water irrigated soil properties due to improvement in soil pH, EC followed by reduced concentration of heavy metals. The results of soil analysis indicate that the selected mushroom species is able to bio-remediate the high heavy metals (Cr, Cu, Pb and Zn) concentration from contaminated soil. Results also indicated the need of further cultivation of mushroom to bioremediate the heavy metals (Cr, Pb & Zn) up to safe level in contaminated site soil. The highly significant negative correlations was found between pH and Cr, Pb & Zn; Significant positive correlation was between organic matter and Cu, Pb & Zn; Electrical conductivity (EC) and Cr. Bioaccumulation of heavy metals in mushroom has significantly decreased the yield parameters (color, total numbers of buds, average height, pileus diameter, stem thickness, total mass and ash content) and biochemical values (protein) in mushroom during the both first and second cultivation. Significantly higher nutrient contents (Ca, Fe, K, NO3- & PO42-) were found in comparison to control indicated the presence of high nutrient content in soil due to wastewater irrigation. Cr, Cu, Pb and Zn were significantly bioaccumulated in both first and second cultivated mushroom in comparison to control indicating the better bioaccumulation potential of selected species mushrooms. Cr and Pb metal levels were found higher than maximum permissible limit (FAO/WHO, 2001) for mushroom sample cultivated on experimental site soil for both first and second cultivation indicating the possible heavy metals related health hazards upon consumption of contaminated mushroom as well as further pollution after their improper disposal. Other heavy metals will also be future health hazard at selected site if the current practice of mushroom or any agricultural crop and vegetable production will be continued in long run without proper heavy metal remediation.Item Fuel Briquette Potential of Lantana Camara L. Weed Species and its Implication for Weed Management and Recovery of Renewable Energy Source, in Ethiopia(Addis Ababa University, 2015-09) Sintayehu Abebe; Seyoum LetaThis study aimed to produce fuel briquettes and weed management in ecofriendly manner from Lantana camara, which is most serious invasive weed, spreading throughout the world particularly at alarming rate in Ethiopia. Utilization of biomass like invasive weed such as lantana camara L. species in Ethiopia have greater advantage for discovery of clean renewable energy sources and for reduction of deforestation of indigenous trees. Producing and evaluation of the fuel briquetting potential of root, stem, branch and leaves and the charcoal potential of root, stem,and branch of Lantana camara L. weed species were carried out by using ASTM procedure. The mean average value for fixed carbon content(FCC) and calorific value of the root, stem ,branch and leaves fuel briquette of Lantana camara L sample were:53.89±1.84(%)and6525.54±250.03(cal/gm); 52.77±0.39% and 6479.59± 1004.51(cal/gm );50.22 ± 3.21(%) and 5135.36± 150.29 (cal/gm); 37.56 ± 0.69 (%) and 3690.67 ± 182.32 (Cal/gm); respectively. The result for fixed carbon content(FCC) and calorific value of the root, stem and branch of charcoal produced Lantana camara L sample were:65.6(%)and 7483.99(Cal/gm);6.44(%) and 7483.99(Cal/gm);64.89(%) and 7222.66(Cal/gm);respectivelyThe finding show that by ecofriendly utilization of lantana camara weed as a clean energy fuel briquette. it‟s possible to manage the spread of such type alien invasive weed as well as to increase farmers crop production, access for livestock grazing land;reduce deforestation of indigenous trees and reduce indoor air pollution.Item Effects of Soil Conservation Practices on Selected Soil Nutrients in Borodo Watershed, Ethiopia(Addis Ababa University, 2015-09) Mamaru Assefa; Mekuria Argaw; Tesfaye ShimbirSoil degradation is evident in the mountainous areas of Ethiopia and is often represented as results of human pressure. It can be reduced through different Soil and Water Conservation (SWC) measures. The study was conducted at the Borodo watershed, which is situated in Dendi district, west shewa zone of oromya region in Central highlands of Ethiopia. The aim of the study was to assess the effect of soil conservation practices on selected soil nutrients in different land use systems in Borodo watershed. The results of the soil analysis showed that most of soil physicochemical properties had significant variations with respect to Soil Conservation practices, land use types and slope gradients. The highest average mean values of exchangeable Ca (40.05meq/100g), Mg (19.17meq/100g) and CEC (53.14 Cmol /kg) were observed under the forest land as compared to the lowest values (14.54, 5.11 and 32.92 Cmol/kg) in the unconserved lower eucalyptus and Upper grazing lands respectively. The cumulative values of land use changes without proper management were negative (decreasing the marginal status of soil nutrients). The results of the study indicates that soil bunds could benefit farmers through improving the nutrient status of the soil better if integrated with biological structures (stabilizing bunds with vetiver and other improved forage seeds). For optimizing and maintaining the favorable soil physicochemical properties sustainably farmers need to know the appropriate soil conservation structures, their application and benefits.Item Two-Phase Anaerobic Reactor Coupled with Microalgae Photobioreactor for Slaughterhouse Wastewater Treatment and Bioenergy Production(Addis Ababa University, 2023-10) Dejene Tsegaye; Seyoum LetaIn Ethiopia, the transformation from agricultural to agro-industrial based development contributed to an increase in the number of agro-processing industries such as slaughterhouses, which discharge its process wastewater to the environment with partial or no treatment. Uncontrolled and regular disposal of partially treated or untreated wastewater into the water body has significant impacts on the environment and humans. The objective of this study was therefore to evaluate the pollutant removal efficiency and bioenergy (biogas and biodiesel) production potential of an integrated biological treatment system composed of two-phase anaerobic reactor and microalgae photobioreactor treating slaughterhouse wastewater. The experiment was conducted using two consecutively connected forty-liter galvanized metal anaerobic batch bioreactors (hydrolytic-acidogenic and methanogenesis reactors) integrated with a 9000-cm3 microalgae photobioreactors. From the results of the hydrolytic-acidogenic phase, a hydraulic retention time (HRT) of three days and an organic loading rate (ORL) of 1788.81 mg COD/L*day offered optimal reactor stability and performance. Thus, highest degree of hydrolysis of 63.92%, degree of acidification of 53.26%, soluble chemical demand (3430.2 ± 80.44mg/L), and total volatile fatty acids (1176.50 ± 81.66 mg/L) were achieved for hydrolytic-acidogenic reactor operating at indicated condition. The NH4+-N concentration varied from 278.67 to 369.46 mg/L, which is not in a range that would affect the reactor’s stability. The results from methanogenesis phase also revealed improved stability and performance of the system with peak operating parameters: total volatile fatty acid (TVFA) = 520 ± 19 mg/L; Total Alkalinity (TotA) = 1424 ± 10 mg/L; TVFA: TotA. Ratio = 0.36; salinity = 1172 mg/L, pH = 6.92) were found at a HRT of six days and an OLR of 298, mg COD/L*day. Additionally, highest removal efficiency for COD = 81%; volatile solid (VS) = 95%; biogas production = 185 ± 4 mL; and methane yield = 0.03 per mg COD consumed were achieved at HRT of 6 days and OLR of 298 mg COD//L*day. Moreover, the system showed good performance in terms of methane yield (67%) and methane production rate (123 mL/day). The results from the two-phase anaerobic digestion operated at optimal hydrolysis and methanogenesis reactors operating conditions showed substantial organic matter (TCOD (82.87%), TDS (93.32%), turbidity (98.0%6)) but low nutrient (TN (57–63%) and TP (27.57%)) removal efficiency. At the polishing step using microalgae photobioreactor, removal efficiencies above 85% were found for COD, TN, NO3-N, NH4+-N, TP, and PO4-3–P. The average crude lipid content of Chlorella, Scenedesmus, and co-culture microalgae biomass was 15.70 ± 1.27%, 17.75 ± 1.08%, and 21.65 ± 1.03%, with 72-79%, 67-78%, and 71-81% biodiesel content, respectively. The variation in lipid and biodiesel content was significant (p ≤ 0.05) between the treatments. In general, the integrated two-phase AD and microalgae photobioreactor showed removal efficiencies of greater than 90% and 95% for nutrients (TN, NH4+-N, NO3-N, TP, PO4-3–P, and SO4-2) and organic matter (BOD, SCOD, and TCOD), respectively. The bioenergy produced from the integrated system in terms of methane and biodiesel were 128.40 mL/day and 67-81%, respectively. Furthermore, a two-phased AD system integrated with Chlorella, Scenedesmus species, and the co-culture exhibited final effluent concentrations below the permissible discharge limit for slaughterhouse effluent standards of Ethiopia for all pollutants. Therefore, it can be concluded that the two-phase AD system integrated with microalgae photobioreactor used to treat slaughterhouse wastewater in this study has implications for circular economy approach by converting this biowaste into valuable products. The treated final effluent can also be reused for non-potable domestic purposes such as floor cleaning, irrigation, and greenery purposes, which in turn guarantee sustainable practices.Item Design of Eco - Friendly Hybrid Electricity Options for Centeral Rift Valley Climatie Condtions, Ethiopia(Addis Ababa University, 2024-10) Mintesnot Gizaw; Getachew BekeleEnergy poverty in Sub-Saharan Africa necessitates innovative and sustainable solutions. This dissertation addresses this challenge by investigating low-carbon hybrid microgrid systems (MiGs) for electrifying a typical 250-household remote community in the Ethiopian Central Rift Valley (E.C.R.V.). The study focuses on integrating renewable energy sources (wind, solar, floating photovoltaics - FPV) with diverse storage technologies (lithium-ion batteries, pumped hydro storage - PHS). To assess the region's renewable energy potential, wind speeds were measured at various heights throughout a year and analyzed alongside solar radiation data from existing databases (PVGIS 5.2, NASA Power). This comprehensive evaluation revealed significant potential for both wind and solar energy generation, informing the design of sustainable MiGs. Additionally, the potential for pumped hydro storage (PHS) was assessed using LiDAR-based digital elevation models (DEM) with a resolution of 12.5 meters, identifying Tedecha Island, with its unique volcanic crater pond, as a prime location for a small-scale PHS system. Leveraging this natural feature, a novel MiG design incorporating the Energy-Water-Food Nexus (E-W-F-N) was proposed, aiming to optimize excess energy for water management and agricultural productivity. Extensive simulations and optimization using HOMER Pro, PVsyst, and MATLAB identified optimal hybrid systems tailored to the specific needs of mainland and island communities. For the mainland, a 35.8 KW solar PV system, 20.4 KW wind turbines, and 72 KWh lithium-ion batteries proved the most cost-effective, with a levelized cost of electricity (LCOE) of $0.190/KWh. For the island community, the lowest-cost option was a 41 KW solar PV coupled with a 254 KWh PHS system (LCOE: $0.061/KWh), highlighting the potential for locally available resources to reduce costs. An alternative 32.2 KWp (FPV-PHS) configuration was also identified, showcasing a 7% higher energy yield and significant water savings (2.19 m3/m2/year) compared to land-mounted PV, at a reasonable LCOE of $0.140/KWh. Sensitivity analysis of the land-based PV-PHS system revealed its robustness under varying conditions, achieving an LCOE of $0.0882/KWh while maintaining 75% of PHS capacity, thereby yielding a surplus of 750 m3 of water annually for EW-F-N applications. This demonstrates the system's potential to simultaneously address energy and water scarcity challenges. Furthermore, this dissertation addresses critical gaps in the literature by proposing a novel microgrid design paradigm that incorporates the Energy-Water-Food Nexus (E-W-F-N) and developing a comprehensive methodological framework for designing and evaluating FPV-based systems, particularly small-scale (20-50 KWp) configurations. This research confirms the technical and economic feasibility of hybrid MiGs within the Ethiopian context, offering a pathway to expand electricity access and foster sustainable development in the E.C.R.V. and similar regions. The study's focus on small-scale FPV-PHS systems and E-W-F-N integration provides valuable insights for the widespread adoption of sustainable energy solutions in underserved communities. Future research directions include exploring the integration of bioenergy, assessing the long-term performance of mainland systems, conducting a detailed geological assessment for the PHS reservoir, and investigating the use of locally-sourced materials for FPV platforms to further enhance sustainability and cost-effectiveness.Item Zr-BDC MOF as a Sustainable Catalyst for Efficient Hydrolysis of Lignocellulosic Biomass(Addis Ababa University, 2023-12) Getahun Getachew; Ahmed Hussen; Abi TadesseLignocellulosic biomass, such as plant matter and agricultural residues, is a major source of renewable organic carbon on our planet. Of this lignocellulose, 40–50% is composed of cellulose that serves as a valuable feedstock for the production of fuels, chemicals, and various industrial applications. Cellulose can be converted into glucose through a process called hydrolysis. The hydrolysis of cellulose using homogenous acids is known to have drawbacks due to the generation of a large amount of toxic and corrosive wastes, making the use of heterogeneous catalysts like metal organic frameworks (MOFs) crucial for eco-friendly cellulose conversion. In this study, Zr-BDC MOF was synthesized sustainably using water as the sole green solvent, at room temperature, and without modulation. The as-synthesized Zr-BDC MOF exhibited a semi-crystalline structure with desirable properties such as a specific surface area of 380.367 m2/g, a pore volume of 0.55cm3 and a pore radius of 13.24 Å. The evaluation of this MOF as a solid-acid catalyst for the hydrolysis of lignocellulosic biomasses, specially Sugarcane bagasse and Pineapple peels was conducted for the first time in this study. Under optimum conditions, a mixture of 4 g biomass (Sugarcane bagasse or Pineapple peels) and 0.8 g Zr-BDC MOF in 100 mL distilled water was hydrolyzed at 130 oC for 4 h. The hydrolysis process yielded 0.60 mg/mL and 2.044 mg/mL of total reducing sugar (TRS), mainly glucose, from the hydrolysis of Sugarcane bagasse and Pineapple peels, respectively. These promising results demonstrated the potential of Zr-BDC MOF as an alternative catalyst for the hydrolysis of lignocellulosic biomass, enabling the conversion of cellulose to glucose for bioethanol production. The use of Zr-BDC MOF offers economic feasibility and environmental friendliness, addressing the challenges associated with homogeneous acid hydrolysis. Furthermore, this study can serve as a benchmark for future research on catalytic application of MOFs in biomass conversion to glucose for bioethanol production.Item Land Use Management Practices on Selected Soil Properties, its Impact on Soil Erosion and Land Use Land Cover Changes in Kabe Watershed, Blue Nile Catchment of Northern Ethiopia(Addis Ababa University, 2024-06) Fikru Assefa; Teshome Soromessa; Eyasu EliasAlterations in land-use management strategies like the cultivation of steep slopes, overgrazing, or limited fallow periods, and slope position affect the physiochemical properties of soils. Transitioning land from forest cover to cultivated areas could diminish organic residue inputs, potentially resulting in decreased soil fertility, increased rates of soil erosion, loss of soil organic carbon and nutrients, and an accelerated rate of soil degradation. In this study, we assessed the impacts of land-use management on selected soil physiochemical properties under various terrain slopes and with & without soil and water conservation (SWC) measures in a disturbed landscape in the Kabe Watershed of the northern part of Ethiopia by using composite and core soil samples for laboratory analysis. Also, we explore farmers’ decision to adopt soil and water conservation (SWC) practices by structured questionnaire survey and focus group discussion methods applied to collect the necessary information from farm plots and households. Hundred households with 282 sampled plots were interviewed and several fields were visited during transect walks. The Tobit regression model in SPSS was used for analysis. In addition, data were analyzed using descriptive statistics. On the other hand, we estimate soil loss in different land-use systems and slope categories using the Revised Universal Soil Loss Equation model with the help of the ArcGIS process applied for this study. It was analyzed in Ethiopian conditions by using data of erosivity (R) based on interpolation of rainfall data, soil erodibility (K), vegetation cover (C) and satellite images, topography slope and steepness (LS), and conservation practices (P). Ultimately, we analyze and forecast the patterns of land use land cover alterations from 1986 to 2019 within the research region through the utilization of qualitative and quantitative data gathered via Geographical Information System (GIS) and remote sensing (RS) methods. Field observations and consultations with local elders were additionally utilized to confirm the findings obtained from remotely collected data. According to the findings, for all slope positions with and without soil and water conservation (SWC), SM content, TP, silt, and clay proportions of soil were lower in the cultivated land compared with grazing and forest land use types. Relatively, soil BD and sand fraction were higher in the cultivated land than in grazing and forest land use types. The terrain slope position influenced the sand content of forest, grazing, and cultivated land types, with an increase observed from lower to upper slope positions. In contrast, the silt and clay fractions generally decreased from lower to upper slope positions. Available phosphorus (P) and organic carbon (OC) levels were consistently below the standard across all land use types (LUTs). In addition, the mean soil loss was relatively highest (20.01 t ha-1yr-1) under cultivated land followed by grassland (0.69t ha-1yr-1) and it was lowest (0.17 t ha-1yr-1) under forestland given that the average soil erosion across the entire watershed was 6.95t ha-1yr-1. In addition to this, 90% of local farmers believed that soil erosion was controlled by different rehabilitation techniques. According to the analysis of geographical information system (GIS) and remote sensing (RS) data, the expansion of cultivated land, forest lands, and grazing lands exhibited a consistent and gradual increase throughout the period between 1986 to2019, primarily at the cost of shrubs and wetlands. In summary, to conserve both soil & water resources and rehabilitate the watershed, policymakers need to implement appropriate land conservation strategies based on land-use structure & slope difference. Lastly, this study recommended an involvement of the concerned body to end the fast deprivation of shrubs and wetlands in the watershed.Item Prediction of Wind Energy Potential Using Artificial Intelligence and Empirical Models: a Case Study in Major Parts of the Wello Highlands, Ethiopia(Addis Ababa University, 2024-02) Kefelegn Shewangzaw; Natei Ermias; Eyale Bayable; Yedilfana SetargeBecause of the natural fluctuation in wind energy availability between the dry and wet seasons, where hydropower reservoirs experience varying water levels, wind power can serve as a vital supplement to hydroelectric power within Ethiopia's energy framework. Because wind power increases system reliability even during dry seasons, it becomes an essential component of the grid energy mix. This study has focused on predicting wind energy potential in the mountainous Wello highlands region upper basin of Abay and Tekeze of Ethiopia using Artificial Intelligence (AI) and empirical models. Wind speed data from four locations (Wegertena, Lalibela, Amdewak, and Ambamalyam) and eight years data (2013-2020) was used to develop AI and Empirical models for the prediction of wind energy. Long short-term memory (LSTM) neural networks provided the highest accuracy in modeling wind speed, capturing complex seasonal patterns and explaining more than 97% of the variance. On the side of wind power density, all four models at all study sites perform very accurately, scoring above 98.8%, but the gradient boost is the advanced model from the other models at 99.9% only wind power density simulation. The evaluation metrics consistently show that the AI model outperforms the empirical methods on all tasks. LSTM architectures can incorporate long-term weather context, resulting in significantly improved predictions compared to snapshot models that lack native sequence understanding. Accurate wind energy forecasting supports the expansion of renewable infrastructure to sustainably meet Ethiopia's rapidly increasing electricity demand. This study also demonstrates the effectiveness of modern AI in the complex spatiotemporal modeling of wind resources. This provides evidence that deep learning approaches such as LSTM are uniquely positioned to capture diverse wind dynamics based on real-time time series dependency modeling. Accurate wind energy forecasting will be critical as Ethiopia pursues an ambitious sustainable development and decarbonization path over the coming decades. Integrating AI-powered platforms into renewable energy planning and operations will facilitate optimized wind farm site selection and grid integration toward national green energy goals.Item The Role of Area Exclosures for Soil and Woody Vegetation Rehabilitation in Hawzen District, Northern Ethiopia(Addis Ababa University, 2024-05) Zufan Gebremariam; Eyasu EliasContinuous loses of biodiversity and soil fertility in northern Ethiopia particularly the mid-highlands of Tigray have become serious threats as the consequences of anthropogenic processes. To overcome such problems, the government and peoples of Tigray Regional State has been practicing on soil and water conservation initiatives for decades. This study investigated the woody species composition, structure, regeneration, density and diversity in the area exclosure and in grazing area; and to assess the socioeconomic importance of area exclosure to the local communities. A total of 70 sample plots were used, 35 plots in exclosure and 35 in the grazing area.With in transects, nested quadrats having a size of 20 m × 20 m, 4m × 4m and 1m×1m were laid out to collect biophysical data. In each plot, heights, diameters and numbers of existing woody species were recorded. A total of 56 and 22 woody species were recorded in the Exclosure and Grazing area, respectively, belongs to 33 families in exclosure and14 families were recorded in the grazing area.The result showed that the densities (ha-1) of the woody species 1903 in the Exclosure and 30 In the Graznig ara were determined. Total basal area (m2ha-1) 71.01 for the Exclosure and 29.07 for the Grazing area were calculated Acacia albida and Acacia tortilis, Acacia etbaica woody species were the dominant species in the study site. High species richness was found in the Exclosure than the Grazing area. The population structures in each Exclosure were healthier and higher in recruitment potential than the adjacent Grazing area which was almost hampered. To assess the socioeconomic importance of the area exclosure, survey, and focus group discussions were made. The majority of the local people expressed a positive attitude towards the benefits of area exclosure in rehabilitation of woody species in the area. The impact of area exclosure on soil quality was assessed using soil physicochemical parameters such as soil organic matter, cation exchange capacity, total nitrogen, available potassium, available phosphorous, pH, electrical conductivity and texture. Fourteen soil samples were taken randomly from the two sites (7 from each), and analyzed. Soil laboratory analysis result revealed that the exclosure had significantly (p <0.05) higher levels for OM, CEC, TN, Av Ca,Av Mg and AvK compared to the grazing land.This showed that excluding degraded communal grazing lands from human and livestock disturbances is a viable option to restore degraded woody species in the mid-highlands of Tigray. To enhance the recruitment potential of some rare species, appropriate silvicultural practices are highly recommended for the Exclosure. Thus, wider promotion of exclosure in the region and across the nation should be guided by a scaling up strategy, formulated on the basis of lessons drawn from effective exclosure establishment and management practices.Item Synthesis, Characterization and Fabrication of TPA-Derivative Based Dye Sensitizer Using TiO2 Nanoparticles for DSSCs(Addis Ababa University, 2024-06) Frehiwot Gashaw; Yedilfana Setarge; Mekonnen AbebayehuSolar energy is a renewable energy source that can meet the world's growing energy demand, reduce carbon dioxide emissions, and replace fossil fuel energy. However, the production costs of silicon-based solar cells are still too high for them to compete with the conventional energy sources available on the market. Dye-sensitized solar cells (DSSCs) show to be an attractive choice with the potential for lowering production costs. To increase the efficiency of DSSCs, new sensitizer development is crucial. The donor (D)- spacer (π)-acceptor (A) framework offers appropriate molecular structures for molecular design that work as efficient light harvesters, and electron injection into the semiconductors of the sensitizers has a significant effect on the DSSCs' performance. This study was conducted to synthesized, fabricated, and analyzed TPA derivative of metal-free organic dye-sensitized solar cells using a novel approach that combined computationally with the Gaussian 09 W software program to calculate the optimal structure and electron distribution of the two synthesized dye molecules using density functional theory (DFT) at the B3LYP functional and 6-31G ++ (d, p) basic set levels and experimental methods (Suzuki-Miyaura coupling reaction and Knoevenagel condensation).The dye FG1 (4'-(diphenylamino)-[1,1'-biphenyl]-4-carboxylicacid) & FG2 ((E)-2-cyano-3-(4' (diphenylamino)-[1,1'-biphenyl]-4-yl) acrylic acid) TPA derivative-based solar cell device offered the VOC, JSC, fill factor (%FF) characteristics of (0.55, 0.57) V, (3.75,13.35) mA/cm2, and (42.81, 27.04), respectively. It was shown that solar cells made from the anchoring group carboxylic acid (FG1) produced a PCE of 0.88 %. Similarly, devices (FG2) with a PCE of 2.10% were built from the cyanoacetic acid anchoring group due to better structural geometry, Photon absorption and efficiency have been increased by the addition of the cyanogroup and the double bond, as confirmed by UV-Vis’s absorption, NMR and FTIR spectra. Based on the various anchoring groups, energy gaps showed that the studied molecules' energy gaps, FG1 and FG2, are 3.34 and 2.62 eV, respectively. Hence, this study showed that the cyanoacetic acid anchoring group can improve the semiconductor TiO2 nanoparticle's efficiency and charge transfer.Item Impacts of Land Use and Land Cover Changes on Land Surface Temperature, Soil Erosion and Soil Quality Deterioration in Suha Watershed, Northwestern Highlands of Ethiopia(Addis Ababa University, 2024-07) Nigussie Yeneneh; Eyasu EliasSuha watershed found in the Upper Blue Nile Basin of Ethiopia is facing severe soil erosion and soil quality degradation problems due to its biophysical and socioeconomic characteristics. However, there is a lack of comprehensive data on the land use land cover changes and their impacts on land surface temperature, soil erosion risk and sediment yield, soil quality indicators as well as soil nutrient flows and balances in this watershed. Therefore, this study was undertaken to analyze the spatiotemporal changes in land use and land cover and to examine their impacts on the land surface temperature, soil erosion and sediment export, soil quality indicators and soil nutrient flows in the Suha watershed, northwestern highlands of Ethiopia. Multi-temporal Landsat images covering the periods from 1985 to 2019 were utilized to examine changes in land use and land cover (LULC) as well as land surface temperature (LST) variations with the application of GIS and remote sensing techniques. The process involved image preprocessing, supervised classification, accuracy assessment, and change detection. Quantification of soil loss and sediment export was carried out using the Revised Universal Soil Loss Equation (RUSLE) integrated with ArcGIS. Various data inputs, including digital elevation model, LULC, precipitation, soil types, and conservation strategies were used for this purpose. To evaluate the status of soil quality indicators, a total of 27 composite surface soil samples (0-30 cm) were collected from adjacently located land-use systems in three replications from each elevation gradient of the watershed. Standard procedures were applied to analyze selected physical and chemical soil quality parameters. The study also investigated soil nutrient depletion by quantifying nutrient flows and balances for macronutrients (N and P) in different elevation gradient of the watershed. Significant changes in land use and land cover were observed in the Suha watershed over the past 35 years. Agricultural land has increased by 15,418 hectares for the entire period at the expense of grazing and shrub lands. Barren land also expanded significantly due to cultivation of marginal and steep slope areas and poor land management. The study also revealed spatial and temporal variations in Land Surface Temperature (LST), with impermeable surfaces having the highest values. The average annual soil loss rate in this watershed varied over the years, with rates of 15, 22, 31, and 30 tons per hectare per year for the periods 1985, 1999, 2009, and 2019 respectively. The mean annual sediment yield was 4, 6, 8, and 8 tons per hectare per year for the same periods. Soil loss varied across different land use and land cover categories and landscape positions, with the highest mean value observed in bare land (54-103 t/ha/yr), followed by cultivated land (17-29 t/ha/yr). About 32% (25,660 ha) of the watershed experienced severe and very severe soil erosion in the past 35 years. The analysis of variance results of soil quality indicators showed significant changes in selected soil quality indicators across different land use systems. Specifically, the index of soil aggregate stability (ISS), organic carbon (OC), total nitrogen (TN), and C: N ratio revealed significant decreases in the cultivated land use system compared to other land use systems. Conversely, the content of available phosphorus (AP) was significantly higher in cultivated land. Moreover, the aggregated soil quality index (SQI) values have shown that soil quality is rated as low in cultivated fields, optimal in grazing land and high in forest land. The results of soil nutrient balances indicated that the rate of nutrient depletion is higher in the highland areas than the midland areas. N and P balances were -77.1 kg N /ha/yr and -11.9 kg P/ha/year for the wheat farming system (highland area), which are rated as one of the highest in Africa. For teff farming system, the values were -39.3 kg N/ha/yr and -1.4 kg P/ha/yr. The major negative drivers are removals in the harvested products (OUT1) and crop residues (OUT2) followed by soil erosion (OUT5). Overall, these studies provide valuable insights into the changes in land use/land cover, land surface temperature, soil erosion risk, soil quality and nutrient balances, contributing to a better understanding of the environmental dynamics. Sub watersheds that are found on the steep slope landscapes and are experiencing severe soil erosion that demand immediate interventions. effective soil and water management strategies should be established and integrated with vegetative measures to provide multiple benefits to the farmers. In order to reduce the volume of crop residue removal as household energy (OUT2), promoting energy saving technologies such as the use of fuel stoves, saving stoves and biogas is crucial.Item Assessment of Micro-Plastic in Surface Water and Sediment of Lake Aba Samuel, Addis Ababa, Ethiopia(Addis Ababa University, 2024-01) Michael Girimay; Tadesse Alemu; Selamawit GebremedhinMicroplastic is a growing global concern with significant environmental implications in Ethiopia, there is limited study to identify the level of microplastic pollution in all environmental compartments. Therefore, the objective of this study is to assess the composition and the extent of microplastic pollution in surface water and sediment of Lake Aba Samuel located in Addis Ababa, Ethiopia. Samples were collected from three sampling points, for water samples using a stainless-steel sieve and a pump-assisted filtration device while the sediment sample was collected using a grab sampler. Sodium Iodide (NaI) was employed for density separation, and Sodium Dodecyl Sulfate (SDS), Hydrogen Peroxide (H2O2), and Potassium hydroxide (KOH) were utilized to remove organic matter. microplastic particles were quantified and photographed using a stereomicroscope equipped with a digital camera. Additionally, SEM captured the morphology of microplastic, and the polymer composition was determined through FTIR analysis. The abundance of microplastics was recorded in mean values ranging from 24 to 52.33 particles/L and 39.67 to 73.69 particles/Kg in water and sediment samples, respectively. The sampling site and abundance of microplastics in water and sediment samples were statistically significant at P<0.05. The size of microplastics <100μm was abundant in both sample types. Fragments and fiber with transparent and blue colors of MPs were present in a large number. Polyethylene (35%), polypropylene (25%), polyethylene terephthalate (14%), polystyrene (18%), and other (8%) were contained in the water sample. In the sediment, sample polyethylene terephthalate (35%), Polyethylene (25%), Polyvinyl chloride (20%) polypropylene (10%), polystyrene (5%), and other (5%) were contended. The NPI value of the lake was 0.55, which indicates light pollution, and the PHI value of the lake was 32.87, which is below the threshold value and suggests minimum risk. The findings of the study emphasize the need for prompt action. To prevent more contamination and protect the ecological integrity of urban water bodies such as Lake Aba Samuel and other Ethiopian lakes, it is crucial to implement policy interventions, effective waste management techniques, regulations on plastic usage, and public awareness programs.Item Photocatalytic Degradation of 2, 4-D Based Pesticide from Surface Water and Industrial Waste by Using TiO2-CuO-Clay Soil Composites(Addis Ababa University, 2024-05) Sisay Demisse; Tadesse Alemu; Mekonnen AbebayehuPesticides are artificially synthesized organic and inorganic compounds that are used to control weeds and increase agricultural productivity. Nowadays pesticide contaminants are a major source of surface water pollutants. Repeated pesticide usage in the soil causes runoff that raises the concentrations of pesticides in surface water. For instance, Ziway Lake whose size is 7300 ha is contaminated with agricultural runoff every year. To resolve the problem of environmental pollution a lot of methods and technologies have been developed hither to, some of these technologies are either, inefficient or too expensive to be used widely. The main goal of this research is photocatalytic degradations of pesticides from surface water and Industrial waste by TiO2-CuO-Clay soil composites. The morphology, particle size and the resulting TiO2-CuO-Clay soil composite were characterized by XRD, SEM and FTIR. The composite catalyst was optimized by varying concentrations. The degradations of pesticides from surface water and pesticide factory effluents were done by UV-vis Lamp with wavelength 280 nm and the sample was retained for 2, 5, 7 and 9 h. The optimum pH value used was 4. After the irradiation of UV-vis light the degradation efficiency of 2,4-D was analyzed by HPLC. The effectiveness of pesticides removal was impacted by dopant proportions. Moreover, it was found that the removal efficiency of pesticides increased with increasing irradiation time and nanoparticle concentrations. Pesticides removal efficiency decreases with increasing pesticides concentration and contact time with respect to light intensity. Degradation efficiency of TiO2-CuO-Clay soil nanocomposite was 96.18% and 99.84% respectively from surface water and pesticide factory effluent. The study’s result shows that, TiO2-CuO-Clay soil nanocomposite is the effective photocatalyst for pesticides degradations from surface water and industrial waste.Item Soil Characterization, Investigating Phosphorus Sorption Capacity and Response of Crops to Liming and Phosphorus on Acid Soils of Bako Tibe and Omo Nada Districts of Oromia Region, Ethiopia(Addis Ababa University, 2024-06) Berhanu Dinssa; Eyasu EliasSoil characterization is essential for understanding the properties, causes, and effects of acidic soils and devising appropriate management options. Soil acidity and phosphorus fixation are major causes of soil fertility decline and crop yield reduction in Ethiopian highlands. The high P-fixing property of soils makes available P below crop demand. A study was conducted to characterize and classify agriculturally potential acid soils, assess phosphorus sorption capacity, determine the external P and lime requirement of different soils, and evaluate the response of wheat to phosphorus application rates in the study area. Four soil types were considered, and twelve representative Pedons were opened and described. A total of 97 (52 disturbed and 45 core ring, undisturbed) soil samples were collected from identified horizons and examined in the field and laboratory for soil characterization. The soils were categorized into different reference soil groups (RSG). Phosphorus-sorption data were obtained by equilibrating 1 g of the 12 soil samples with 25 ml of KH2PO4 in 0.01 M CaCl2, having 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, and 330 mg P L-1 for 24 hours. The relationship between phosphorus sorption and soil characteristics was established by correlation analysis. The magnitude of the soil's phosphorus sorption capacity and external P requirement were affected by clay content, exchangeable acidity, organic matter, Al2O3, and Fe2O3. Alisols had the highest Kf value (413 mg P kg-1), followed by Luvisols (336 mg P kg-1), Andosols (280 mg P kg-1), and Nitisols (280 mg P kg-1). Nitisols, Luvisols, Alisols, and Andosols, had an external phosphorus requirement of 25, 30, 32, and 26 mg P kg-1 soil sequentially. After assessing the degree of acidity of the soils, 2.28 t ha-1, 3.60 t ha-1, and 4.22 t ha-1 lime was determined (based on the exchangeable acidity method) for Nitisols, Luvisols, and Alisols respectively. The integrated effects of lime and P fertilizer on maize yield parameters and selected soil chemical properties were examined on Nitisols, Luvisols, and Alisols for two years (2017/18-2018/19) under field conditions. The experiment consisted of eight treatments: (T1) control, (T2) 50% RL + 30 kg P ha-1 + 92 kg N ha-1, (T3) 100% RL +30 kg P ha-1 + 92 kg N ha-1, (T4) twice RL + 30 kg P ha-1 + 92 kg N ha-1, (T5) 50% RL + 15 kg P ha-1 + 92 kg N ha-1, (T6) 100% RL alone, (T7) farmers Practice (200 kg NPSB +92 kg N ha-1), and (T8) 30 kg P ha-1 + 92 kg N ha-1. Soil analysis results after harvesting showed that the addition of lime increased the soil pH and exchangeable Ca2+ but decreased the levels of soil exchangeable acidity for all soil types. The Olsen available P content of plots treated with recommended lime plus critical P rate increased from 6.69 to 15.42 mg kg-1 in Nitisols, 6.71 to 22.27 mg kg-1 in Luvisols, and 5.27 to 40.92 mg kg-1 in Alisols. The application of recommended lime + critical P rates increased maize grain yield by 89.88%, 81.49%, and 84.38% over the control treatments and by 28.35%, 26.53%, and 26.73% over farmers' practices for Nitisols, Luvisols, and Alisols, respectively. Therefore, the use of twice the critical P level (60 kg P ha-1) alone or the use of critical P level combined with the recommended lime rates by soil types can be used for optimum maize production in the study area. The study also found that the use of 40 kg P ha-1 which produced the maximum wheat grain yield of all treatments can be recommended for wheat production.Item Health and Economic Impact Estimation of Ambient Air Particulate Matter (PM2.5) Pollution in Addis Ababa Using BenMAP-CE(Addis Ababa University, 2024-04) Mulugeta Getachew; Andualem Mekonnen; Desta FitsumAmbient air particulate matter (PM2.5) pollution poses a significant health and economic burden in Addis Ababa, Ethiopia. This thesis used the Environmental benefits mapping and analysis program-community edition (BenMAP-CE) software tool to estimate health and economic impact of ambient air PM2.5 pollution. The study evaluated the impact of decreasing the annual average PM2.5 concentration in 2019 (32.8μg/m3) to different international and national air quality standards, including World health Organization`s guidelines and the Ethiopian National Ambient Air Quality standard (NAAQS). Results showed that Addis Ababa exceeded both WHO`s and Ethiopia`s ambient air quality standards in 2019. The study estimated the attributable deaths from cardiovascular, ischemic heart disease (IHD), stroke, chronic obstructive pulmonary disease (COPD) and lower respiratory infection (LRI) due to PM2.5 exposure across three reduction scenarios. Additionally, economic benefits associated with avoided deaths were quantified using the Organization for Economic Cooperation and Development (OECD) Value of Statistical Life (VSL) methodology. The finding demonstrated that reducing PM2.5 pollution levels led to a notable decrease in mortality rates from various health conditions in Addis Ababa. Moreover substantial economic benefits, amounting to millions of dollars, were observed across all health endpoints, indicating significant societal savings. This study underscores the importance of implementing interventions to mitigate PM2.5 pollution for improved public health and economic well-being in Addis Ababa and similar urban settings.Item Composition and Structure of Woody Species of Legay Forest in Seden Sodo Woreda, South West Shoa, Ethiopia(Addis Ababa University, 2024-07) Abdudin Chibsa; Gemedo Dalle; Bikila WarkinehThis study was conducted in Legay forest to determine the woody composition, structure and regeneration status of the Legay forest. Systematic sampling method was used to collect vegeta-tion data from fifty-two plots of 20 m x 20 m for woody plant species, and 5 m × 5 m was used for sampling of seedlings and saplings plants. The sampling plots were placed at every 200 m intervals on flat and 50 m altitudinal difference on sloppy areas and the parallel transect lines laid at 500 m apart. Diameter at breast height (DBH) of all woody species was measured by us-ing a mater tape. Data was analyzed using descriptive statistics and R software. A total of 57 woody species belonging to 54 genera and 46 families were identified. Fabaceae was the most dominant family represented by four species followed by Asteraceae, Lamiaceae, Myrtaceae, Oleaceae, and Rosaceae, which shared three species each. The main five plant communities identified from the study sites were Olea europaea-Rytigynia neglecta, Rhus glutinosa - Rosa abyssinica, Dodonaea angustifolia -Quercus sp., Maytenus undata- Carissa edulis and Pol-yscias fulva- Euclea divinorum. The density for mature woody species, seedlings and saplings were 157, 475.8 and 310 individuals ha-1, respectively. The basal area of the forest was 69.22 m2 ha-1. Plant species with greater IVI in Legay forest were Carissa edulis, Rytigynia neglecta and Euclea divinorum. The plant species that had lowest IVI and calling for conservation priority were, Cupressus lusitanica, Dovyalis abyssinica, Solanum incanum, Asparagus acutifolias and Salvia officinalis.The population structure of the forest indicated that the lower storey (57.25%) dominant than the middle (27.72%) and upper storey (15.02%). Regeneration status of the forest indicated that the total density of seedlings and saplings of woody plants species of the forest were 570.29 and 407.77 ha-1, respectively and that of mature individuals was 261.81 ha-1, indi-cating that mature plant species were selectively cut. To minimize negative effects on the forest and make sustainable use of it, this study suggests implementing community-based participatory forest management in the area.Item Modeling Soil Erosion and Mapping its Risk in the Dura Watershed of the Upper Blue Nile Basin in North Western Ethiopia(Addis Ababa University, 2024-06) Yitbarek Aemro; Mekuria ArgawModeling soil erosion and mapping land use and land cover dynamics is critical for the estimation, management, and sustainability of current and future natural resources and improving the quality and quantity of agricultural products. It emphasizes soil erosion as a major environmental threat, causing significant economic losses and reduced agricultural productivity. The main objective of this study was to model soil erosion and map its risk in order to determine erosion vulnerability in the Dura watershed on the upper Blue Nile basin using the HEC_HMS model integrated with GIS and remote sensing. The impact of LULC change on the magnitude of surface runoff and soil erosion was assessed using MUSLE model and statistical tools in HEC-HMS. The effect of LULC change, on surface runoff, sediment load for the water and soil resources, and watershed management for sustainable Natural resource management was evaluated. The result showed that, forest area experienced a decline of 10.9% from 1993 to 2013, followed by a noteworthy recovery of 26.2% by 2023. Notably, bush land displayed the most substantial growth rate (84.9%) across the entire period, with a particularly sharp increase (45.5%) from 2013 to 2023. Agricultural land exhibited a peak in 2013, with a 46.4% increase from 1993, but then decreased by 23% by 2023. The area of bare land witnessed the most dramatic decline (95.8%) from 1993 to 2023, demonstrating a consistent decrease across each decade. Higher values indicate better agreement between model predictions and observations. These findings validate the suitability of the HEC-HMS model for runoff simulation. Notably, the upper sub-watershed exhibited higher surface runoff, soil erosion rates, and sediment yield compared to the lower sub-watershed in 1993. Specifically, SB1 experienced an erosion rate of 4.56 t/yr, which more than doubled to 11.76 t/yr by 2010. Similarly, SB2 witnessed a substantial increase from 8.27 t/yr in 1993 to 10.79 t/yr in 2010. The sediment yields for Sub-Basins 1, 2, and 3 were 45.15 t ha⁻¹ yr⁻¹, 28.9 t ha⁻¹ yr⁻¹, and 5.81 t ha⁻¹ yr⁻¹, respectively. In contrast, Sub-Basin 13 had a lower sediment yield of 0.031 t ha⁻¹ yr⁻¹. These results underscore the combined impact of land use/land cover changes, topography, rainfall patterns, and agricultural activities within the watersheds. Generally, LULC increases the watershed, decreases the traction power of rainfall, reduces soil loss and sediment yield in the watershed, increases the infiltration rate of the soil, reduces the magnitude of surface runoff. In order to enhance the quality and quantity of soil and hydrological components, it is important to expand reforestation efforts and consistently monitor shifting patterns. This will help identify areas that are particularly susceptible to erosion. By doing so, we can improve water absorption into the groundwater system, which will have positive impacts on agricultural productivity, water resources, and ecological sustainability in the surrounding area. Additionally, these efforts will also have social, economic, and environmental benefits, as they directly influence soil and water resources and watershed management in the Dura River watershed.Item Development of Microfluidic Paper Based Analytical Devices (Μ-Pad) for the Determination of Organophosphate and Carbamate Pesticides from Environmental Samples(Addis Ababa University, 2023-06) Sheleme Beshana; Ahmed HussenThis thesis focuses on the development of microfluidic paper-based analytical devices (μ-PADs) and sample preparation techniques, namely dispersive liquid-liquid microextraction (DLLME) and the combination of QuEChERS (quick, easy, cheap, effective, rugged, and safe) with DLLME for colorimetric determination of organophosphate (OP) and carbamate (CM) pesticides from water and lettuce samples. In the colorimetric quantification, the yellow color is generated by the interaction between acetylcholinesterase (AChE), acetylthiocholine iodide (ATChI), and 5, 5- dithiobis- (2-nitrobenzoic acid) (DTNB). The digital image of the yellow color was captured and analyzed using a Canon scanner and ImageJ software, respectively. Key experimental conditions (concentrations and volumes of AChE, ATChI, and DTNB, incubation time, storage stability, and image capturing time) were systematically optimized using a univariate approach. Under optimized conditions, the method showed a wide linear range (1-16 mg L-1), repeatability (3-5% RSD), and intermediate precision (7-10% RSD), and robustness (≤ 1.85% RSD), with R2 ≥ 0.9945. Limits of detection (LOD) were in the range of 0.24-0.33 mg L-1. An acceptable mean recovery (87-94%) was observed at a 1 mg L-1 fortification level. Following that, the μ-PAD operational parameters (reagent concentrations and volumes) were optimized using multivariate techniques based on the Box-Behnken design (BBD). The analysis of variance revealed that high regression and fitting values were obtained between the experimental and predicted responses at a 95% confidence level. Satisfactory linearity (R2 ≥ 0.9990) in the range of 0.5-16 mg L-1, LOD (0.12-0.17 mg L-1), repeatability (3.75-7.98% RSD), intermediate precision (7.15-10.98% RSD), and accuracy (78-97%) were achieved. The results of the univariate and multivariate optimization were compared and found that the multivariate optimization requires a much lower concentration of the reagents and improved LOD values of the univariates by 29-64% for the studied pesticides. Therefore, the multivariate approach has been demonstrated to be more efficient and effective than the univariate approach. For further improving sensitivity, the μ-PAD was coupled with an enrichment method called DLLM. The experimental parameters (volume of hexane and acetone, extraction time, and salt amount) were optimized using response surface methodology (RSM). The enrichment factors (EF) and LOD values were found in the range of 317-1471 and 0.17-0.41 μg L-1, respectively, which is below the maximum residue limits of EU for drinking water. The matrixmatched calibration curve showed a wide linear range (0.625-40 μg L-1) with R2 ≥ 0.9968. The obtained extraction recovery varied from 79-97% with repeatability (2.21-6.01% RSD) and intermediate precision (5.60-10.41% RSD). Thus, the proposed method is low cost, easy to operate, efficient, and sensitive, showing great potential for the determination of pesticides in water samples. Finally, the combination of QuEChERS, DLLME, and a μ-PAD was developed for the extraction, preconcentration and quantification of target analytes from lettuce samples, respectively. RSM using Plackett-Burman and central composite design were used for the screening and optimization of significant factors, respectively. The matrix-matched calibration curves held excellent linearity (R2 ≥ 0.9988) in the range of 0.01-0.64 mg kg-1. The EFs and LODs were 21-31 fold and 0.006-0.009 mg kg-1, respectively. The recoveries were in the range of 79-97% and good precision was obtained with RSD below 11%. Thus, the experimental results revealed that the QuEChERS-DLLME method is suitable for the routine pesticides analysis from lettuce vegetables in terms of high accuracy, precision, and efficiency.Item Enhanced Chlorella Vulgaris Species Derived Biodiesel Production Through Transesterification Reaction Using Heterogeneous Nanocatalyst(Addis Ababa University, 2024-05) Mesifin Gebreyohanes; Yedilfana SetargeThe goal of the research project is to produce biodiesel utilizing oil from the Chlorella vulgaris species using a heterogeneous potassium impregnated calcium oxide (K/CaO) catalyst that is made from calcite with an average size of 38.1906 nm. Chlorella vulgaris Oil extraction from harvested, dried, and ground up microalgae was carried out using a microwave-assisted n-hexane and methanol mix solvent extraction method, and the physicochemical properties were determined. Microalgae were isolated and cultured in BBM under illumination of 2500lux light intensity from non-heat releasing white florescence 12:12 hour dark and light cycle. The density, kinematic viscosity, acid value, saponification value and free fatty acids were recorded as 0.87 g/ml, 35.51mm2/s, 1.93mgKOH/g of oil, 212.81mg/g of oil, and 0.88% respectively. The factors that affect the biodiesel yield were investigated. An optimum yield of 94% biodiesel was obtained at reaction temperature of 50 0C, 5% catalyst load and 13:1 alcohol to oil molar ratio and 60 minute time. The biodiesel's physicochemical qualities were assessed, and the outcomes were contrasted with ASTM criteria. Density at 20oC (811kg/m3), kinematic viscosity (4.7 mm2/s), acid value (0.459mgKOH/g of oil), free fatty acid (0.23%), and flash point (124 oC) were listed as the physicochemical characteristics of the biodiesel produced. The findings suggested the possibility of algal oil as a feedstock for the biodiesel sector, which could be used as an alternative fuel source, and the fuel qualities were found to be within ASTM criteria.