Africa Center of Excellence for Water Management
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Item Land Use and Land Cover Changes in Relation to Ecosystem Services in Lake Koka Catchment(Addis Ababa University, 2024-06) Tensay Teshome; Tadesse FetahiLake Koka, a rift valley lake in Ethiopia, provides critical ecosystem services (ESs), such as hydroelectric power generation, domestic water supply, irrigation, recreation, and fisheries. However, the lake is severely threatened by anthropogenic activities, particularly land use and land cover change (LULCC) in the catchment area. This study aimed to map and quantify the dynamics of ESs, specifically the trophic status index, nutrient delivery ratio, and socioeconomic impact associated with LULCC in the Lake Koka catchment from 1991 to 2021. Landsat images were analyzed using ARC GIS 10.7.1, ENVI v5.3, and ERDAS IMAGINE 15 software to assess LULCC. The Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model was employed to estimate nutrient delivery ratios. Five major land use types were identified, with increased settlements and forestland over the study period. The trophic status index indicated a hypertrophic state in the lake. These results suggest that LULCC and anthropogenic activities have drastically impacted the ESs provided by the watershed, particularly provisioning services. Deforestation and the expansion of agricultural land, coupled with using fertilizers, pesticides, and insecticides, have led to increased nutrient and chemical transport to lakes through runoff, resulting in eutrophication and frequent algal blooms. In general, the catchment's ecosystem services are greatly affected by changes in LULC.Item Numerical Groundwater flow Modelling of Gur Catchment, Central Ethiopia(Addis Ababa University, 2023-09) Urgessa Hirpa; Dessie NedawThis study focuses on the numerical modeling of groundwater system in the Gur catchment, located in central Ethiopia. The catchment covers an area of 530 km2 and exhibits diverse topographic features, including gorges, flatlands, and ridges, with elevations ranging from 1402 to 3341 m. The climatic classification of the catchment falls on Dega (Alpine vegetated zones), Woina Dega (temperate zone), and Kola (hot zone) climatic zones, with mean annual rainfall ranging from 1029 to 1198 mm and average temperatures ranging from 14.4 to 16.5 °C. Land cover analysis reveals that approximately 83% of the study area is covered by cropland. The geological formations in the study area comprise Mesozoic sedimentary rock units, Tertiary volcanic rock units, and Quaternary superficial sediments. The hydrogeological units identified in the catchment include moderately productive porous aquifers, moderately productive fissured aquifers, and aquicludes consisting of gypsum and mudstone. Two methods, namely the Chloride Mass Balance and WetSpass Model, were employed to derive groundwater recharge estimates, yielding an average value of 104.5 mm/year. Groundwater recharge estimation using the WetSpass Model indicates that the catchment receives an annual runoff of 426 mm (39% of precipitation), evapotranspiration of 561 mm (51% of precipitation), and groundwater recharge of 106 mm (10% of precipitation). The numerical groundwater flow model developed for the Gur catchment demonstrates satisfactory calibration results, with simulated hydraulic heads closely matching observed values. The model predicts a total inflow water balance of 246974 m3/day and an outflow of 246972.7 m3/day, with a small discrepancy of 1.3 m3/day. Scenario analysis reveals that increased groundwater extraction leads to a decline in water levels, while reduced recharge results in a significant decrease in hydraulic heads. Combining decreased recharge and increased groundwater abstraction intensifies the decline in water levels. These findings provide valuable insights into the hydrogeological dynamics of the Gur catchment and contribute to sustainable groundwater management in the region.Item Remote Sensing Based Evapotranspiration Modelling for Irrigation Performance Assessment in Jedeb Watershed, Upper Blue Nile Basin, Ethiopia(Addis Ababa University, 2024-10) Yilkal Gebeyehu; Yilkal Gebeyehu; Abebe DemissieAccurate actual evapotranspiration (ETa) data, alongside irrigated area maps, are important for assessing temporal and spatial irrigation performance indicators, which are critical for improving water resource monitoring, management, and sustainability. This study compared machine learning algorithms on the Google Earth Engine platform (GEE) in irrigated area mapping, customized the surface energy balance for land–improved (SEBALI) model using high-resolution land use/cover (LULC) data and implementation in Python, and evaluated the performance of a small-scale irrigation scheme using remote sensing (RS) and ground truth data in northwestern Ethiopia over two irrigation seasons. The study used Sentinel-1, Sentinel-2, and Landsat 8 satellite data and European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis v5 (ERA5) climatic data as the main inputs. The accuracy of irrigated area mapping was evaluated relative to the inputs and agroecology, and the accuracy was improved by incorporating monthly SAR and vegetation index data. Random forest was a consistent classifier in different agroecological zones and inputs. The Python version of the SEBALI model (SEBALIGEEpy) was validated over croplands using publicly available AmeriFlux flux tower eddy covariance data. In addition, the ETa from SEBALIGEEpy was compared with the ETa simulated using the Soil & Water Assessment Tool Plus (SWAT+) model, which was calibrated with observed discharge, and with the FAO’s remote-sensing based Water Productivity Open Access Portal (WaPOR). The results show that SEBALIGEEpy provides more accurate evapotranspiration estimates with fewer missing records and has the potential to be used for agricultural water management. Thus, the performance indicators, including equity, adequacy, overall consumed ratio (OCR), and productivity, were evaluated using SEBALIGEEpy results and ground truth data. The scheme showed good equity, with coefficient of variation (CV) values of 1.90 and 1.63 for the two seasons, alongside satisfactory water distribution among fields and within the field. The overall consumed ratio (OCR) was 0.54 and 0.43 for the two seasons. The mean crop water productivity (CWP) of wheat estimated from SEBALIGEEpy was 2.49 kg/m3. This study revealed the potential of using remote sensing to evaluate irrigation performance and water productivity per field within small-scale irrigation schemes.Item Enhancement of Nonerevenue Water Management Using Integrated Model: a Case of EXMO Zone Water Distribution System, Addis Ababa(Addis Ababa University, 2023-10) Yosan Legesse; Esayas AlemayehuNonrevenue water is one of the resisting problems for water utilities in developing countries. The lack of detail information on system condition is intensifying the challenges. To address the problems, understanding the condition of water distribution system is fundamental. Thus, the study focused on model based enhancement of nonrevenue water management and conducted in ex-main office (EXMO) hydraulic zone of Addis Ababa water distribution system. The integrated model of GIS and Water-GEMS was used to evaluate existing conditions. The water balance software used to analysis the nonrevenue water. As the result, the nonrevenue water of the zone was 44.58%, the hydraulic analysis showed 84.48% and 41% of the nodes received recommended pressure 15m to 60m while 4.81% and 27.18% of pipes experienced recommended velocity 0.6m/s to 2m/s during minimum and peak demand respectively. Similarly, the high water age 72 to 146 hours was simulated. Based on the assessment results, the potential vulnerable area in the zone was discovered and the improvement was done by redesigning the system and coupling it with leakage control practices. The improvement result showed 86% of nodes and 77.29% pipes achieved the pressure and velocity requirement during peak demand respectively while the water age was reduced to 56 to 78 hours. The improvement strategies used to decrease water loses by accelerating the procedures to fix and repair leakages. Thus, geospatial and hydraulic model integration approach is significant tool to enhance nonrevenue water management by diagnosing network, exploring and predicting the future challenges and solutions.Item Estimation of Sedimentation of Koka Hydropower Reservoir Using Bathymetric Survey Awash Basin, Ethiopia(Addis Ababa University, 2023-11) Yalelet Mulat; Fasikaw AtanawReservoir sedimentation is a serious problem globally as it significantly reduces the original capacity of reservoirs and affects irrigation, hydroelectric power generation, drinking water supply, flood control, and other recreational activities. Sediment capture through reservoirs is a major concern for Ethiopians, who have many large natural and artificial reservoirs. This study was conducted in Koka reservoir in Oromia region Upper Awash basin with the objectives of estimating reservoir sedimentation and life of Koka hydropower reservoirs using bathymetric survey. To estimate reservoirs sediment deposition comparison of initial reservoirs capacity, and present capacity of the reservoir that was obtained by bathymetry survey developing of TIN surface and analyzing volume of reservoirs using Surfer, and ArcGIS 10.8 Software’s were essential . According to the current bathymetric survey, the capacity of Koka Reservoir has been reduced from 1850 Mm3 in 1960(during first impounding) to 1049.9 Mm3 in 2023. The result showed that Koka reservoirs have lost 43.2% of its total capacity due to sedimentation in 63 years of operation period. The total amount of sedimentation was estimated to be 800.1 Mm3 with in an annual rate of loss of reservoir 12.7 Mm3/year. The study indicated that the dead storage volume has been totally lost and 577.1 Mm3 of the live storage zones are occupied by sediments this shows that the live storage zones have been losing 34.6 % of its storage capacity after 63 years of operation.Item Treatment Performance and Fate of Heavy Metals in a UASB and Trickling Filter Based Sewage Treatment Process: the Case of Kality Centralized Sewage Treatment Plant, Addis Ababa, Ethiopia(Addis Ababa University, 2023-12) Ashrake Hussen; Andualem M.Heavy metals pose a significant challenge to UASB and trickling filter-based sewage treatment plants due to retention, accumulation, limited solid-liquid separation, low sludge production, and anaerobic conditions, posing environmental risks like soil contamination and health issues due to impeded processes and inhibited microorganism activity. The study was aimed to investigating the Treatment Performance and Fate of Heavy Metals in a UASB and Trickling Filter Based Sewage Treatment Process in Kality Centralized Sewage Treatment Plant, Addis Ababa. A study was conducted to measure the levels of heavy metals in effluents and sludge using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES. The results found in the study showed that value of pH, BOD5, COD and TSS were in the range from 6.75±0.04 - 7.54±0.13; 6±0.73 -383.7±74.58 mg/l; 53±2.21 -728.33±121.03 (mg/l) and 1.33±0.19 - 345.33±61.9 (mg/l), respectively. Similarly, NH4-N 20.9±2.56 - 45.4±4.14 (mg/l); TN 52.17±4.24 - 58.2±3.79 (mg/l); TP 26.35±1.77 -27.7±2.31(mg/l); SO4-2- 17.98±2.54 - 48.4±2.65 (mg/l); EC 591.83±31.21 - 855.33±43.7 (μs/cm), while for heavy metals; Pb Below Detectable Limits (BDL); Ag BDL – 63.5±13.5 mg/kg; Ba 60±4.47 μg/l – 1291±58.5 mg/kg; Fe 13.33±3.33 μg/l - 16538.5± 15192 mg/kg; Al BDL - 2358.5±662.5 mg/kg ; Cd 0 μg/l - 0.35±0.15 mg/kg; Cr 0 μg/l - 10.5±0.65 mg/kg; Cu 0 μg/l - 23.85±1.15 mg/kg; Zn 5.45±12.3 μg/l - 165±5.4, and Mn 165 ± 49.5 μg/l - 92.5±3.75 mg/kg. The treatment plant demonstrated exceptional efficacy in reducing physicochemical parameters and heavy metals, meeting the standards set by the Ethiopian Environmental Protection Authority and the World Health Organization, and the attainment of discharge limits for surface water bodies could be attributed to adsorption, precipitation, and bio-sorption processes. To optimize and improve future processes, ongoing data collection and monitoring of seasonal physicochemical parameters and heavy metal levels in the sewage treatment facility would be beneficial.Item Enhanced Cadmium Removal from Aqueous Solutions by Immobilized Activated Carbon on Textile-Coated Inclined Plates(Addis Ababa University, 2024-09-30) Gilbert Chifundo; Yonas ChebudeThe rapid increase in population and industrial growth has led to the generation of large amounts of wastewater, which in turn has an impact on the water quality. Studies have shown that global increase in industrialization is one of the major contributors of heavy metals in wastewater. Common heavy metals found in wastewater include cadmium, chromium, arsenic, lead, mercury and nickel among others. These metals pose risks to aquatic ecosystems and human health, with potential effects including neurological, cancer and developmental issues. The strict regulations governing wastewater discharge require effective treatment techniques. Adsorption has gained popularity as one of the methods for water and wastewater treatment owing to its relative simplicity, efficiency and cost effectiveness. Adsorption for water and wastewater treatment has been widely studied over the past decade, and has mainly focused on the use of low-cost renewable adsorbents for pollutants removal. Activated carbon is considered as one of the favorable adsorbents for use in adsorption process due to its enhanced surface area. The use of activated carbon (AC) as an adsorbent in water and wastewater treatment has been limited to laboratory scale due to among other things the powdery form of most activated carbons which pose a number of limitations for industrial application. The use of powdered activated carbon (PAC) is hindered by such challenges as adsorbent-adsorbate separation after adsorption process leading to secondary pollution, and regeneration of the spent adsorbent material which leads to loss of the valuable adsorbent through leaching. Even though granular activated carbon is used to overcome these challenges, its use is only limited to batch and column adsorption configurations. These challenges, along with others discussed in this study have hindered the large-scale implementation of the adsorption technique in wastewater treatment systems. This study aimed at developing an innovative wastewater treatment process that integrates the inclined plate settlers (IPS) and Composite Adsorbent Coating (CAC) for heavy metal removal from aqueous solutions in a continuous set-up in an effort to boost the use of adsorption for large-scale industrial applications. The first part of this study focuses on the preparation of activated carbon from Prosopis juliflora (PJAC) wood by pyrolysis and chemical activation. The objective was to assess its effectiveness as an adsorbent for synthesizing CAC for heavy metal removal. The influence of impregnation ratio (IR), carbonization time (t), and carbonization temperature (T) on the Cd2+ percent (%) removal was evaluated using the Box-Behnken Design (BBD) of the Response Surface Methodology (RSM) (Design Expert software version 11). v The results indicated that all the variable preparation factors were significant (p< 0.05) in the Cd2+ removal by PJAC with T being the most significant (p < 0.0001). At the optimum conditions of IR=1.8, T=595 ºC and t=174 min, the model predicted a 99.9% Cd2+ removal efficiency while the adsorption experiment obtained a 96.7% removal efficiency, respectively. The SEM images of the optimized PJAC revealed a rough and porous morphological surface with an SBET of 600.4m2/g and a near neutral pHPZC of 6.92. These findings highlighted the potential of utilising invasive plants like Prosopis Juliflora as effective adsorbents for removing heavy metals. Later the prepared PJAC was then used to prepare the CAC to overcome the challenges associated with powdered activated carbon (PAC) in water and wastewater treatment. CAC was synthesized using a simple sol-gel method for the simultaneous reduction of Cd2+ and Cr2O72-. The CAC was also characterized by various techniques. Statistical analysis confirmed that pH and contact time significantly (p < 0.0001) affected both metal ions removal. Using the optimized conditions (pH=8.5, CAC dosage=0.25, adsorbate concentration=5mg/L, contact time=30 min and temperature=23.73°), the predicted and experimental ion removal efficiencies were 86.86 and 83.98% for Cd2+ and 94.26 and 58.08% for Cr2O72-, respectively. The Langmuir adsorption isotherm was the best-suited model (R2 > 0.99), while the metal ions removal was regulated by the PSO kinetic model (R2 > 0.999). The batch adsorption process was endothermic and spontaneous, as indicated by thermodynamic values (− ΔG°, +ΔH°, +ΔS°). The study only observed a 10% decline in the Cd2+ removal effectiveness of the CAC after three adsorption-regeneration cycles (with 0.1 M HCl of pH 0.3 as the eluent), indicating its stability for heavy metal removal. The final part of the research aimed at developing an innovative method for treating wastewater, an Inclined Plate Adsorber (IPA). The effects of angle of plate inclination (𝜃𝑝), influent flow rate (Q) and adsorbate initial concentration (Ci) on Cd2+ percent removal efficiency (%) were studied. At optimized operating parameters (θ=45˚, Q=5 ml/min and Ci=1.87 mg/L) the IPA Cd2+ predicted (R2=0.9926) and experimental removal efficiencies were 75.8% and 69.7±4.67%, respectively. The adsorption capacity (mg/g) of IPA calculated using the breakthrough curve analysis (BTCA) was 9.6 mg/g. Comparing IPA performance with a tank without plates and a tank with plain plates, the Cd2+ removal efficiencies were 2.4±0.1% and 4.6±1.1%, respectively, confirming that the dominant pollutant removal mechanism in an IPA system is adsorption. Additionally, breakthrough curves were acquired for various Q, Ci, and 𝜃𝑝. The results underpin the potential of using IPA for industrial wastewater treatment and enhancing the use of adsorption on a larger scale.Item Evaluation of the Hydraulic Performance of Water Supply Distribution Systems Using Watergems for Optimal Water Management: a Case of Nifas Silk-Lafto Sub-City, Addis Ababa, Ethiopia(Addis Ababa University, 2024-06-23) Ismail Abib; Tamru TessemeEnsuring an adequate and sustainable potable water supply in urban areas of developing countries is often challenging. This study aimed to evaluate the performance of the water supply system in Nifas Silk Lafto, Addis Ababa, Ethiopia using WaterGEMs. The study also examined the water supply distribution system of the sub-city, focusing on the challenges and opportunities for improvement. The Water Geospatial Engineering Modeling System (WaterGEMS) was employed to analyse the hydraulic performance of the distribution network. An intermittent supply and continuous supply scenarios were created based on customer meter data to check the system performance and ability to meet the current demand in the sub-city. Non-Revenue Water NRW and water coverage were also assessed to discover supply adequacy and overall losses. In the intermittent supply scenario, analysis showed that 95% of nodes receive optimal pressure within the range of (15-70 meters). In contrast, Continuous modelling results in only 27% of nodes having pressure within the range. Approximately, 72.3% of nodes experienced excessive pressure exceeding (>70 meters), risking infrastructure issues. The performance analysis demonstrated that nearly 87% of pipes operate below the optimal minimum velocity (0.6 m/s) and 11.78% of pipes operate within the recommended velocity. The results also indicated that the maximum daily water demand exceeds production by 29,990.28 m³/d, resulting in 58% of the water supply for residents. Non-revenue water computation exemplified about 55% of total service water, highlighting a need for better management practices. The study findings highlight that pressure management strategies must address excessive pressure, optimise flow velocities to ensure efficient water distribution, and target interventions to bridge the significant supply and demand gap. The study also suggests implementing a systematic leak detection program using advanced technologies like acoustic sensors and ground-penetrating radar. Regularly inspect and maintain infrastructure, meter connections with high-accuracy meters, and increase surveillance through remote monitoring. Conduct water balance analyses and develop alternative water sources, ensure sustainable management, and involve communities in planning and education.Item Clay-Based Microbial Fuel Cell System for Petroleum Refinery Wastewater Treatment and Green Energy Generation Simultaneously(Addis Ababa University, 2024-08) Kabo Benedict; Girum Ayalneh; Addis SimachewThe increasing demand for energy and the growing concern for environment pollution have led to the exploration of sustainable and efficient methods for wastewater treatment coupled with energy recovery. Microbial Fuel Cell have emerged as a promising technology to convert organic matter in wastewater into electricity.This study was focusing on the application of clay based (MFC) microbial fuel cell as a novel approach to treat petroleum wastewater while simultaneously generating electrical energy by using microorganisms extracted from diesel oil-contaminated soil collected from old garage. In this study, microbial fuel cells (MFCs) were constructed using low cost ceramic cylindrical pot (900ml) as an ion exchange membrane. An inoculum derived from oil-contaminated soil, 10% of the volume of the anode inoculum was fed to the anode chamber for MFC1, MFC2 and no inoculation was added to the MFC control. The cathode chamber was filled with 1M potassium ferricyanide in a 1M phosphate buffer solution at a ratio of 1:1. All MFCs were operated in batch mode with synthetic petroleum wastewater containing (810 ml) for 30 days for open circuit voltage and at an external resistance of 10Ω, 100Ω, and 1000 Ω for 14 days for closed circuit voltage. Carbon cloth (projected surface area of 546cm2and 455.22 cm2) was used as both the cathode and anode respectively. The treatment efficiency of clay-based MFCs were evaluated by the removal efficiencies of COD and BOD. For MFC1, BOD removal efficiency of 89%, COD removal efficiency was 96%, and maximum daily open circuit voltage of 188.92 mV. MFC2 demonstrated BOD removal efficiency of 91%, COD removal efficiency of 98%, and a maximum average daily open circuit voltage of 210.35 mV. In contrast, MFC control displayed lower removal efficiencies with BOD removal efficiency of 49%, COD removal efficiency of 30%, and a maximum average daily open circuit voltage of 58.28 mV. The maximum power density achieved was 9.99μW/cm2 for the highest performing MFC2.These results highlights the effectiveness of MFC1 and MFC2 in terms of organic matter removal and power generation compared to MFC control, displaying the potential of clay-based MFCs for wastewater treatment and energy production. This research just laid a foundation for the use of clay based MFC in treatment of petroleum wastewater and energy recovery, more studies have to be carried out to optimize and maximise its efficiency.Item Impacts of Land Use Land Cover and Climate Change on Surface Water Balance Components of Gobele Watershed in Wabe Shebelle Basin, Ethiopia(Addis Ababa University, 2024-07) Iradukunda Valentine; Habtamu HailuChanges in land use land cover and climate are important global challenges due to the impact on water balance components. Climate change is caused by a change in greenhouse gas concentration due to natural and anthropogenic forcing. This study was conducted in Gobele watershed of the Wabe Shebelle River Basin, Ethiopia. It evaluated the individual and combined impacts of both climate change and LULC change on water balance components. Three historical periods (1990, 2005, and 2020) of Landsat satellite images of the study area were used for LULC analysis using ArcGIS. The Soil and Water Assessment Tool (SWAT) was utilized for the simulation of water balance parameters. Maximum likelihood classification was used to classify historical LULC, and the Cellular Automata-Markov Chain model in land change modeler was used to generate the future LULC forecast. The Statistical Downscaling Model (SDSM) was utilized to generate high-resolution future climatic data from well performed four climate models (ACCESS-CM2, MPI-ESM1-2-LR, ICHEC–EC–EARTH, and CanESM2) and their multi-model ensemble mean was used for impact assessment of climate and LULC change on water balance components. The hydrological response of the basin was evaluated using three scenarios: LULC change alone, climate change alone, and combined climate and LULC change. The future periods were divided into the midterm future (2040–2070) and the distant future (2071-2100). According to the CA-Markov chain model's projection of the LULC change, over the study period, agricultural land and settlement areas will increase while grassland/shrub land and forest land are expected to decline. The climate projection result indicates an increase in both Tmax and Tmin under SSP5.8.5 and SSP2-4.5 and SSP5-8.5 climate scenarios in the midterm (2040-2070) and distant future (2071-2100). Likewise, precipitation will show an increasing pattern in the basin. Under SSP5-8.5, evapotranspiration will increase more by climate change than by LULC change during the baseline period (1990-2020). Furthermore, both stream flow and water yield will increase under all scenarios. Moreover, the SWAT model performed satisfactorily in simulating discharge during the calibration and validation periods at the designated gauging station in the Gobele watershed with R2 and NSE values of 0.86, 0.76, and 0.91, 0.69, respectively. Thus, the results of this study provide valuable information to planners and policymakers for sustainable planning of water resources in the Gobele watershed in the face of climate and LULC change.Item Performance and Optimization Study of Shaped Aluminum Hydroxide/Hydroxyapatite Adsorbents for Removal of Fluoride from Drinking Water(Addis Ababa University, 2024-07) Shina Chepkemoi; Beteley TekolaThe study aimed to investigate the efficacy of shaped Aluminium Hydroxide/Hydroxyapatite composite adsorbent in fluoride removal in continuous column experiments. Spherical and cylindrical shapes of the composite adsorbent were produced and characterized for functional groups, phase composition, and structural characteristics. The performance of breakthrough curves was examined in a continuous column adsorption experimental setup by examining the effects of changing process factors such as flow rate, bed height, initial fluoride concentration, type of binder, and pellet shape. The analysis of the breakthrough curve revealed that the cylindrical pellets outperformed the spherical pellets in terms of adsorption capacities, with 1.34 mg/g and 0.679, respectively. Additionally, the results of the bentonite-binder pellets were significantly lower than those of the corn starch binder pellets. The adsorption capacity decreased with a rise in flow rate and initial fluoride contents and increased with rise in the height of bed. Adams-Bohart Model, Thomas model, and Yoon-Nelson model were used to model the breakthrough curve of different process parameters. The R2 for the Adams-Bohart model was between 0.89-0.96 for different process conditions. The Yoon-Nelson and Thomas model yielded R2 values ranging from 0.92-0.99 for all process parameters. The bed depth service time (BDST) model was employed to illustrate the impacts of bed height on the breakthrough curve and to forecast the breakthrough and exhaustion time of the adsorbent. The reliability of the model was demonstrated by a high R 2 value of 0.987. Central Composite statistical experimental design for optimization showed a good fit to the quadratic model with R2 =0.97 and 1.41 mg/g adsorption capacity at optimum conditions of 15 ml/min flow rate, 10 cm bed height, and 5 mg/l fluoride concentration. Fluoride-saturated Al(OH)3/HAP pellets were successfully desorbed in three adsorption-desorption cycles using 10% sodium hydroxide; the desorption efficiency was 88% in the first cycle, 71% in the second, and 61% in the third.Item Drinking Water Quality in Debre Birhan Town, Amhara Region, Ethiopia(Addis Ababa University, 2024-05) Niguss Seyum; Beteley TekolaWater quality is determined by the physicochemical and biological factors that influence the use of water for household purposes. Health problems associated with water are caused by poor drinking water quality. The study was carried out to determine drinking water quality in Debre Birhan town. 41 water samples were taken from various sources i.e. 12 from boreholes, 3 from reservoirs, 13 water taps within the distribution systems and 13 from household containers. Samples were collected from March to May of 2023. The sample collection was performed according to WHO drinking water sampling guidelines and analyzed in the laboratory using a photometer 7100 based on its procedures. The drinking water quality parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), total and fecal coliforms were analyzed onsite by different instruments. Whereas the chemical parameters such as nitrate, total hardness, calcium, chloride, sulfate, phosphate, iron, copper, fluorides and ammonia were analyzed in laboratory. The drinking water for the town came from groundwater might by affected by several industries, lack of sewerage system which influenced have a direct impact for the pollution of groundwater. Per capita consumption was calculated by dividing annual consumption by the number of people in a town, results a daily consumption of 38.44 L per person. Based on the findings, the result for Debre Birhan's drinking water quality were recorded as pH (7.33–7.76), EC ( 108.5–157.2μS/cm), TDS (54.5-79 mg/l), alkalinity (100–180 mg/l), total hardness( 65-150 mg/l), calcium (18-47 mg/l), chloride (2-10 mg/l), sulfate (0-9 mg/l), phosphate (0.2-2.80mg/l), iron (0-0.6mg/l), fluorides (0.17-1.2 mg/l) and nitrate (1.77-18.08mg/l). The WQI results at the source were classified as excellent 40%, good 47% and poor 13%. On the other hand, 85% and 77% of tap water and household containers samples respectively were under excellent category with the remaining results found in good class. Based on the sanitary assessment survey, 59% of participants store drinking water in containers, 97% responded that containers have lids, 54% stored water in homes, and 48% wash hands after lavatory use. Moreover, the absence of sewerage line system and poor waste management in the town leads to wastewater accumulation in septic tanks and pit latrines. Then it was transported by vacuum trucks and private vehicles. The finding of this study can provide valuable insights for professional in the water sectors, healthcare providers and government and non-government organizations.Item Quantifying Uncertainties of Remote Sensing-Based Rainfall and Evapotranspiration Products for Groundwater Recharge Estimation in the Tikur Wuha Watershed, Rift Valley Lakes Basin, Ethiopia(Addis Ababa University, 2024-08) Tsegamlak Diriba; Fasikaw AtanawGroundwater recharge estimation is important for better groundwater management and decision making. Despite advancements in methods for groundwater recharge estimation and the availability of different methods, the results acquired are still variable and uncertain. Due to its hydrogeological formation, slight recharge variability in the Hawassa basin causes significant groundwater level variability. Therefore, this study focused on investigating groundwater recharge estimation uncertainty caused by input data in the Tikur Wuha watershed. Additionally, this study aimed to investigate the effectiveness of rainfall data assimilation from ground observations and climate hazards group infrared precipitation (CHIRP/S) satellite rainfall estimates (SREs) to decrease the uncertainty of recharge estimations. Accordingly, using a conditional merging procedure, two versions of resampled and spatially bias-corrected CHIRP estimates were merged with ground measurements. Additionally, the physically based fully distributed hydrological model WetSpa was used to simulate 30,000 possible combinations of parameters (i.e. randomly generated through Monte Carlo simulation stratified by Latin hypercube sampling (LHS)) for the three model setups. The M1 model setup was developed based on the rainfall measurements obtained from rain gauge stations scattered in and around the Tikur-Wuha watershed in Ethiopia, and the M2 model setup was developed using bias-corrected SREs of CHIRP merged with relevant ground station records. In contrast, the M3 model setup was executed using version 3.8a GLEAM evapotranspiration. One hundred best-performing parameter combinations were selected for each model setup to generate spatial recharge statistics and assess the resulting uncertainty in the recharge estimates. The results of the applied performance measures (i.e., seven) on the corrected and merged CHIRP SREs show that the percentage of detection (POD) and percent volume error (PVE) improved. Moreover, over the sparsely populated western part of the Lake Hawassa basin, the bias-corrected and conditionally merged CHIRP SREs outperformed the estimates obtained by CHIRPS. However, the devised multistage bias correction was limited in considering dry-day events during bias correction, which affected the bias correction performance of the CHIRPS product. On the other hand, the results of the uncertainty assessment revealed that enhanced spatial recharge estimates can be produced through improved CHIRP-based SREs. The replacement of ET estimates using ground meteorological records with the GLEAM dataset reduced the Cv value by 54% compared to M2. However, uncontrolled irrigation water uses and total recharge from irrigation fields scattered across the Tikur-Wuha watershed were not considered in the study, which is a limitation of the study. Finally, future research should concentrate on methods of fusing to understand the benefits of various approaches and produce more precise rainfall records. Additionally, future studies should consider the contribution of irrigation water to the total recharge of the watershed to analyze recharge uncertainty.Item Determination and Spatial Mapping of the Physicochemical and Biological Characteristics of Sewage of Feeding the Kaliti Wastewater Treatment Plant in Addis Ababa Ethiopia(Addis Ababa University, 2025-02) Zekarias Gelaye; Getachew DagnewUrban development in Addis Ababa usually exerts enormous pressure on the existing sewer network systems. The insufficiency in the performance of the sewer network has become one of the most critical issues in the sewer system sector that requires immediate action. Kaliti Catchment sewer system has problems related to sewer system coverage, manholes overflow, and capacity deficiency. The current study aims to evaluate the city’s main wastewater infrastructure's performance and identify factors affecting the treatment efficiency of the plant, particularly the illegal discharge of toxic industrial waste, from exploring the characteristic nature of sewage within the Kaliti catchment area. Based on laboratory testing, geographic information systems, and statistical software applications, this study maps the physicochemical and biological properties of sewage at various sites. The characteristics of sewage were determined by considering 12 parameters at 20 stations (i.e., a total of 480 tastes were obtained). The laboratory analyses of the sewage samples were performed to determine the pH, temperature, electrical conductivity, total dissolved solids, chemical oxygen demand, biochemical oxygen demand, total coliforms and the concentrations of specific pollutants like phosphorus and nitrogen as well.as the heavy metals. The findings were shows that municipal wastewater is organic in nature, having values of BOD of 505.30±184.26 mg/l, COD of 1221.96±401.97 mg/l, dissolved solids of 697±155.95 mg/l, Electrical conductivity 1206.9±326.44 μs/cm, Temperature 21.88±1.67 °C, PH 7.72±0.17, Total Nitrogen 69.97±19.58 mg/l, Total phosphorus 14.08±3.69 mg/l, Total coliform 24.68x106 ±2.99x106 (per 100ml), Null Chromium mg/l,0.39 ±0.22 mg/l Manganese and0.01±0.02 mg/l Zinc. The spatial mapping was applied for detecting pollution hotspots and illegal sewer connections that could have compromised the city’s main wastewater treatment system's efficiency. It is believed that such findings will inform the Addis Ababa Water and Sewerage Authority (AAWSA), which is mandated to both water supply and sanitation of the city, and other stakeholders about the current state of sewage characteristics, thereby facilitating the implementation of targeted mitigation measures.Item Analyze and Comparison of Steady State and Transient Pressure for DCI and HDPE Pipelines Using the Finite Element Method and Bentley Water Hammer Software(Addis Ababa University, 2024-12) Fayera Mosisa; Tamiru TesemeWater hammer is a common issue in water pipelines; and cause significant damage and disruption. This study focuses on the Dire Dawa city water supply project, analyzing three transmission lines between booster pump station and service reservoirs. These lines are particularly vulnerable to water hammer, as their operation is influenced by the water levels in the two reservoirs at either end. Most existing research focuses on either DCI or HDPE pipelines individually, lacking a comprehensive comparative analysis of their performance under steady-state and transient conditions. This gap limits the understanding of how these materials respond to different operational scenarios. The novelty of this study lies in the combined use of advanced simulation techniques (FEM and Bentley Water Hammer) to directly compare DCI and HDPE pipeline behaviours under both steady-state and transient pressure conditions, as well as hydrostatic pressure resistance, by considering detailed material properties. This integrated approach provides a more reliable understanding than previous isolated studies. This study aims to analyze and compares the transient and steady-state pressure and structural responses of DCI and HDPE pipes. A quantitative research approach examines cause-and-effect interactions among variables. Bentley Water Hammer and FEM (Abaqus) software are used to simulate transient pressure and hydrostatic forces, respectively. Abaqus was chosen for its detailed stress analysis, crucial for safety; while Bentley Water Hammer was selected for its accuracy and user-friendly interface. Input data for the simulations are sourced from the Dire Dawa City Water and Sewerage Authority. The study results indicate that transient pressure higher than steady-state pressure up to 127.63%. Both DCI and HDPE pipes showed the same steady-state pressure across all lines. However, HDPE pipes demonstrate advantages over DCI pipes by reducing the effects of transient pressure by up to 118.3%. Additionally, surge tanks reduce the transient pressure by 128.9% for DCI pipe and 11.7 % for HDPE pipe. When both pipes have the same nominal pressure and size, HDPE pipes experience stress levels that are 64.7% higher than those of DCI pipes. The study finds that transient pressure exceeds steady-state pressure and is a key factor in pipe network design for setting nominal pressure. HDPE pipes demonstrate superior resistance to transient pressure compared to DCI pipes. Incorporating appropriate water hammer protection devices significantly enhances pipe performance. For the Dire Dawa city pipeline, HDPE can replace existing DCI pipes of the same nominal pressure. Further research, including laboratory models, is needed to fully understand steady-state and transient pressures in DCI and HDPE pipes.Item Modelling Spatial Patterns of Runoff, Soil Erosion, and Best Management Practices in the Dirima Watershed, Tana Basin, Upper Blue Nile, Ethiopia(Addis Ababa University, 2025-03-24) Simir Birihan; Tenalem Ayenew (Professor)Soil erosion is a pressing issue in worldwide watersheds, particularly in the Ethiopian highlands which leads to land degradation, deterioration of water resources and reduced agricultural productivity. This problem is not evaluated and researched well particularly in the study area of the Dirima watershed, which spans 162 km² within the upper Tana basin. This study addressed these challenges by modelling runoff-generating areas (RGAs), soil erosion dynamics, and evaluating Best Management Practices (BMPs) using hydrological modelling. To do this, the study was focused on four key objectives: assessing hydrological responses from three soil layers using the XAJ model, identifying and quantifying spatial runoff generation and soil erosion hotspots through SWAT+ and AHP, developing rating curves to estimate streamflow and sediment yields, and evaluate best management practices (BMPs) using the SWAT+ model. The hydro-climate datasets were used for model’s parameter calibration for 1996-2005 and validation for 2006-2009. This study successfully calibrated the XAJ hydrological model for the Dirima watershed in Ethiopia using the DEoptim algorithm, achieving baseline performance measures of RMSE = 12, NSE = 0.76, PBIAS = 10.5%, and R2 = 0.78, and validation performance of RMSE = 3.65, NSE = 0.85, PBIAS = 9.9%, and R2 = 0.85. Projections using CMIP6 climate scenarios (SSP2-4.5, SSP3-7.0, SSP5-8.5) indicate future average Tmax increases of 1.59°C, 1.93°C, and 2.48°C, and Tmin increases of 1.83°C, 2.33°C, and 2.85°C, respectively. Changes in the upper soil layer are projected as follows: evaporation (1.72, 1.71, and 1.79mm), soil moisture (0.63, 0.62, and 0.64mm), and runoff (1.07, 0.97, and 1.18mm) in SSP2-4.5, SSP3-7.0, and SSP5-8.5, respectively. Critically, projected precipitation and streamflow values are consistently lower than ET and temperature across all SSP scenarios, suggesting potential water scarcity challenges requiring proactive water resource management strategies. Analysis of the Dirima River, known for its floods and sedimentation affecting Kolladiba town, involves establishing stage-discharge and sediment concentration-discharge relationships. This study uses a power function for stage discharge, divided into two distinct stage regimes (0.3-3 m and 3-6 m), reflecting varying flow conditions. Sediment transport is modelled linearly across three discharge regimes (0-42, 42-190, 190-560 m³/sec) to account for sediment transport processes and behaviours. These curves are crucial for estimating discharge, flood forecasting, and sediment management in the Dirima watershed, enhancing understanding of watershed responses to environmental changes. Field data updates are essential for model accuracy. The Dirima watershed's water balance analysis reveals significant losses, with acceptable model performance of SWAT+ (Calibration: R²=0.71, PBIAS=-0.9, NSE=0.7; Validation: R²=0.84, PBIAS=-28, NSE=0.76). Prediction uncertainty is characterized by p-factors (53%/58%) and r-factors (61%/67%). Surface processes (53%), soil water (20.9%), and groundwater (20.2%) drive the water balance. High rainfall loss (78-80%) via runoff and evapotranspiration indicates limited watershed storage. In the dry season, evapotranspiration, lateral flow, and return flow increase by 59%, 0.9%, and 39%, respectively. Declining aquifer storage threatens water supplies for Gondar City, Kolladiba town, and industries. Customized water management strategies are crucial to address these challenges. The SWAT+ model and AHPs approaches were used to categorize the Dirima watershed into five RGAs ranging from 1 very low (VL) to 5 very high (VH). This categorization resulted in the VL category accounting for 8%,566 mm of runoff and a sediment yield of 33 t/ha/yr. The "L" category, represents 17% with 606mm of runoff and 53.5 t/ha/yr of sediment yield. The M, category 32% of the catchment, generates 662mm of runoff. The H and VH categories, covering 27% and 16%, produce substantial runoff of 682 and 690.2mm, respectively. Sediment yield reached 186.5 t/ha/year in the VH category. The findings emphasized the need for targeted erosion prevention strategies to mitigate these risks. To mitigate loss, BMPs including terraces (ter), vegetative filter strips (VFS) and grass waterways (GWWY) were evaluated both individually and in combination. The ter reduces surface runoff and sediment yield by 25.46% and 57.32% respectively, while VFS is effective in reducing runoff by 24.58% and sediment by 31.92%. The mean runoff is reduced by 16.97%, and sediment is reduced by 38.21% because of the GWWY. And also, that combining BMPs is synergistically better than individual BMPs alone Comb-1 can reduce runoff by 27.84% and sediment by 62.67%; Comb-2 can reduce runoff by 28.85% and sediment by 64.96%; for the full combination of Comb-3, it has the best performance that can achieve a 33.95% reduction in runoff and a 76.42% reduction in sediment yield. These interventions highlight potential cost savings by preserving soil fertility and improving agricultural sustainability. This study offers insights into sustainable watershed management and supports broader environmental conservation efforts. Also, this study shows the applicability of hydrological models and how much the Dirima watershed contributes to Lake Tana eutrophication and sedimentation. By integrating SWAT+, field data, and BMPs under different climate scenarios, the research provides a framework for effective land and water management strategies in the Lake Tana Basin and similar regions.Item Land Use/Land Cover Change in the Catchment of Northern Bay of Lake Tana, Ethiopia: Ramification for Water Quality and Plankton Community Structure(Addis Ababa University, 2025-05) Flipos Engdaw; Tadesse Fetahi (Professor)Rapid population growth-induced industrialization, urbanization, deforestation, settlement expansion and habitat destruction has emerged as critical drivers of land use/land cover (LU/LC) change on a global scale. The uncontrolled LU/LC change and anthropognic activities, in developing countries like Ethiopia, poses significant environmental threats to water quality and nutrient enrichment. The excessive enrichment with these nutrients emanating from intensive anthropogenic activities has substantially impacted water quality and biodiversity of lakes. The developmet of strategies of restoration or protection of lakes from further degradation necessitates the availability of adequate information on water quality, its environmental drivers and impact on plankton communities. There is, however, paucity of information available on the LU/LC changes, water quality, trophic status, and plankton community structure of the northern Gulf of Lake Tana, Ethiopia. Therefore, this study aimed to assess spatio-temporal changes in water quality, trophic status and plankton community structure in relation to the LU/LC dynamics in the northern Gulf of Lake Tana catchment. ArcGIS software and Landsat imagery were employed to produce maps for LU/LC changes. Samples for the assessment of water quality and plankton community structure were collected from May 2023 to April 2024 from five sampling sites, which were selected based on their proximity to human interference. Physico-chemical parameters were measured in situ or determined in collected water samples using standard methods. LU/LC changes were categorized into six classes with an overall accuracy and Kappa coefficient of 92.2% and 0.86%, respectively. The various LU/LC classes were highly correlated with particular water quality parameters. Settlement and cropland expansion were positively correlated with nutrients (NH3- + NH4+-N), NO3-N, soluble reactive phosphate-phosphorus (SRP), and total phosphorus (TP). Forestation was positively correlated with indicator of good water quality such as dissolved oxygen (DO) and pH, while it was negatively correlated with temperature, electrical conductivity (EC), SRP, and NO3-N demonstrating a strong linkage between LU/LC and water quality. There were significant (p<0.05) variations in various water quality parameters such as temperature, DO, EC and turbidity between the dry and rainy seasons. The mean concentrations of nutrients such as NO3-N (0.48 mg/l), SRP (1.2 mg/l), total nitrogen (TN, 1.27 mg/l), and TP (2.1 mg/l) showed significant spatio-temporal variations, with higher concentrations occuring at the Megech and Dablo sites during the rainy season. The concentrations of SRP, TP, and TN, were slightly higher than the USEPA’s threshold concentrations for causing eutrophication. A total of 113 phytoplankton species belonging to six taxonomic groups and 11 Reynolds functional groups (RFGs) were identified. The predominant RFGs, which collectively accounted for 97% of the total phytoplankton abundance, were M, B, N, D, Lo, P and S2. Other RFGs, such as J and X1-X3, constituted 2.4% and 0.8% of the total abundance, respectively. RFGs exhibited significant association with EC, pH, turbidity, and some algal growth limiting nutrients. Forty-five zooplankton species belonging to three groups (17 Rotifera, 14 Copepoda, and 13 Cladocerans) were identified. Rotifers were the most species-rich group, with Brachionus angularis, B. caudatus, B. falcatus, B. havanaensis, and Keratella tropica being the most abundant. Significant (p<0.05) spatial variations in zooplankton diversity, evenness, and dominance were recorded. Shannon index values ranged from H’=2.98 of the GOR site to H’ =3.49 of the MEG site. Evenness values varied between 0.52 and 0.74, indicating less uniform distribution. In summary, the findings indicated that LU/LC changes and spatio-temporal water quality variations significantly affcte phytoplankton and zooplankton community structure and functions, subsequently impacting the overall health of the ecosystem. Thus, ongoing monitoring and intervention are imperative to avert future ecological imbalances and facilitate the restoration of Lake Tana.Item Enhanced Removal of Pharmaceutical Contaminants from Water Using Electrochemical Oxidation Coupled with Adsorption Process(Addis Ababa University, 2024-05) Wondimu Kebede; Joon Wun (Professor)Pharmaceutical contaminants are emerging water contaminants that have become a growing global concern. These contaminants have been frequently detected in surface water, wastewater and drinking water at trace concentrations. Among the pharmaceuticals, acetaminophen (ACM) and ciprofloxacin (CIP) are extensively consumed as analgesics and antibiotics, respectively, and thus ubiquitously detected in the environment. These contaminants are associated with negative effects on human health and aquatic life. In response to this problem, treatment processes such as electrochemical oxidation (EO) and adsorption have previously been attempted as single treatment systems to remove these pharmaceuticals from water. However, these single treatment systems are highly sensitive to water matrix, and their efficiency is limited when employed in multiple pharmaceuticals removal from complex water matrices. Therefore, this study aimed to elucidate the performance of individual (EO and adsorption) and coupled processes (EO+adsorption) in the removal of these pharmaceuticals from water to investigate the benefit of coupling both processes. The individual EO and adsorption processes were independently optimized and then compared with the EO+adsorption process. The adsorption process was conducted using a chemically activated carbon (CAC) synthesized from bamboo sawdust. The comprehensive CAC characterization results, such as BET surface area, SEM, FTIR, Raman spectroscopy and pHpzc, showcased its remarkable adsorptive properties (high surface area, plentiful functional groups and high porosity). More specifically, the employed chemical activation technique significantly increased the surface area from 565.09 m2/g for raw bamboo sawdust carbon (BSC) to 1158.05 m2/g for CAC. In the batch CIP adsorption system, CAC showed excellent CIP removal efficiency (96%) compared to BSC efficiency (45%). The parameters of CIP adsorption process, such as initial CIP concentration, pH, adsorbent dose, and contact time, were studied and found to have a significant effect on CIP removal from water. The optimal CIP removal (96%) was obtained at CAC dose (0.5 g/L), CIP initial concentration (20 mg/L), pH (7.5), and contact time (46 min). The kinetic data of single component CIP adsorption was well described by the pseudo-second-order model (R2 = 0.999), and both Langmuir (R2 = 0.994) and Freundlich (R2 = 0.972) models provided the best fit for the isotherm data. On the other hand, the single component batch adsorption of ACM resulted in 99.6% ACM removal from water using CAC under optimal conditions of ACM (20 mg/L), CAC (0.5 g/L), contact time (90 min), and pH (8). In this case, the kinetic study revealed that the ACM adsorption process followed the pseudo-second-order kinetic model (R2 = 0.999). On the other hand, the isotherm experimental data were best described by the Langmuir (R2 = 0.987) and Freundlich (R2 = 0.968) models. These results suggest that the adsorption of single component ACM and CIP was mainly controlled by chemisorption process. Moreover, the single component removal of ACM and CIP isotherm analysis revealed that ACM and CIP adsorption onto the CAC was monolayer adsorption onto the heterogeneous surface. The reusability study depicted that CAC can be successfully reused for five consecutive adsorption-desorption cycles in the batch adsorption of single component ACM and CIP. The single component ACM and CIP adsorption study exhibited a greater removal capacity for ACM (192.43 mg/g) than CIP (70.95 mg/g), as predicted by the non-linear Langmuir isotherm model. The competitive Langmuir isotherm model, employed for the simultaneous adsorption of ACM and CIP, predicted a maximum adsorption capacity of 125.31 mg/g for ACM and 65.44 mg/g for CIP. In this regard, the adsorption capacity ratio (qm, binary/qm, single < 1) suggests an antagonistic behavior of these pollutants when they co-exist in the same water matrix. On the other hand, the binary component adsorption of ACM and CIP was best described by the pseudo-second-order kinetic model, indicating that the chemisorption process mainly controlled the adsorption process. Under optimal conditions (inlet ACM/CIP concentration = 10 mg/L, flow rate = 1.5 mL/min and adsorbent loading = 100 mg), the fixed-bed column study showcased the maximum bed capacity of ACM (172.48 mg/g) and CIP (147.67 mg/g), with the highest respective removal efficiency of 44.23% and 37.86% in the binary component adsorption system in . However, the single component column adsorption system achieved a higher removal efficiency of 65.83% (ACM) and 42.59% (CIP). The EO process was also employed for the simultaneous degradation of ACM and CIP in the water. The central composite design (CCD) was employed for optimizing the EO process, and optimal conditions for current density (44 mA/cm2), pH (5.5), contact time (80 min) and initial pollutant concentration (20 mg/L) were obtained. Under these conditions, a removal of 94.5% for ACM and 92.7% for CIP was achieved. The EO process resulted in 65% total organic carbon (TOC) and 90.4% chemical oxygen demand (COD) removal at 240 min under optimal conditions. The EO kinetic study revealed that the degradation of ACM and CIP followed pseudo-first-order kinetics. The coupled process (EO+adsorption) optimization using the Box-Behnken Design (BBD) of the response surface methodology (RSM) technique provided optimal operating conditions for current density (22 mA/cm2), pH (5.5), EO time (40 min), adsorbent dose (0.1g/L) and adsorption time (60 min). Under these conditions, remarkable removal of pharmaceuticals (> 99.9%) and > 99% of TOC and COD were achieved when the EO time was extended to 120 min. Furthermore, the coupled process was employed for the simultaneous removal of multiple pharmaceuticals (20 mg/L of ACM+CIP+ATN (atenolol)+AMX (amoxicillin)) from water under optimal conditions. On top of that, the effect of water matrix on the target pharmaceuticals removal performances of EO, adsorption and EO+adsorption was investigated. These results show that the single processes (EO and adsorption) are highly sensitive to the water matrix compared to the coupled (EO+adsorption) process. Consequently, coupling the EO process with adsorption proved to be effective in addressing the influence of the water matrix, which substantially affected the removal efficiencies of the single processes. Overall, the coupled process demonstrated remarkable performances in single (ACM or CIP), binary (ACM+CIP), multiple pharmaceuticals (ACM+CIP+ATN+AMX), and oxidation by-products removal from diverse water matrices. Therefore, the EO+adsorption can serve as a promising treatment technique for the remediation of recalcitrant and ubiquitously detected pharmaceutical contaminants, such as ACM, CIP, ATN, and AMX from water.Item Comprehensive Study of Lake Zwai and Its Watershed for Sustainable Management(Addis Ababa University Library, 2025) Brook Lemma (Prof.)Zwai Ziway ZewayItem Status of Abijata-Shalla Lakes National Park and Challenges of Sustainability(Addis Ababa University Library, 2025) Brook Lemma (Prof.); Tadesse Fetahi (Prof.)Status of Abijata-Shalla Lakes National Park and Challenges of Sustainability