College of Natural and Computational Sciences
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Item EVALUATION OF AIR POLLUTION CONTROL TECHNIQUES IN MESSEBO CEMENT FACTORY, TIGRAY, ETHIOPIA(Mekelle University, 2025-09-25) Araya GebreyohannesCement production is one of the most emission-intensive industrial activities, contributing significantly to global air pollution and greenhouse gas emissions. This study assesses the effectiveness, limitations, and implementation status of air pollution control techniques and their associated occupational health impacts at Messebo Cement Factory PLC (MCF) in Northern Ethiopia. A mixed-method design was employed, integrating quantitative on-site pollutant measurements (CO₂, NOₓ, SO₂, CO, and particulate matter) with qualitative surveys and clinical health data. Field results indicated that pyroprocessing and raw material handling were the dominant emission sources. CO₂ emissions increased from approximately 78,884 tonnes in 2000/01 to 990,767 tonnes in 2015/16, primarily due to production expansion, while per-tonne emissions remained above international best practice benchmarks. Particulate matter concentrations at raw milling points reached 240 mg/Nm³, exceeding Ethiopia’s national limit of 150 mg/Nm³ and the WHO/IFC guideline of 50 mg/Nm³. Despite the presence of baghouse filters and other emission control systems, frequent exceedances revealed operational inefficiencies and maintenance deficiencies. Survey data from 1,235 respondents, including factory employees and nearby residents, showed that 65% observed visible dust emissions and 76% reported receiving no environmental or safety training. Analysis of clinical records from 2013–2017 further revealed high incidences of respiratory tract infections (up to 22.4%) and dermatitis linked to particulate exposure. The findings demonstrate that current air pollution control and occupational health practices at MCF are inadequate to meet regulatory and safety standards. The study recommends upgrading filtration systems, adopting cleaner fuels, improving occupational health and safety management, and aligning operations with ISO 14001 and IFC/World Bank environmental standards to promote sustainable industrial performanceItem GROUNDWATER POTENTIAL AND WELL YIELD DISCREPANCIES: HYDROGEOLOGICAL CONTROLS, DRILLING CHALLENGES, AND AQUIFER PARAMETER–RESISTIVITY RELATIONSHIPS IN UPPER BILATE RIVER BASIN, MAIN ETHIOPIAN RIFT VALLEY, SOUTHERN ETHIOPIA(Mekelle University, 2025-10-16) Fisseha Teka HailuDiscrepancies in well yields within the Upper Bilate River Basin (UBRB) of the Ethiopian Rift Valley Lake Basin highlight the intricate hydrogeology of its volcanic aquifers and Quaternary deposits. This study examines the influence of drilling-challenges such as partial penetration, well loss coefficient, wellbore storage on yield variations, which may surpass the effects of natural hydrogeological variability. By integrating data from meteorological, hydrological, remote sensing, vertical electrical sounding, and pumping tests with historical well records, key aquifer parameters like transmissivity and hydraulic conductivity are quantified, while empirical relationships between aquifer productivity and resistivity are established. This study's water balance analysis for the Upper Bilate River Basin reveals a semi-humid system with a 254.6 mm annual surplus. A significant wet-season surplus facilitates groundwater recharge, estimated at 58.9 mm/year (6% of rainfall), indicating moderate infiltration and strong surface water-groundwater interaction A hydrogeological framework and groundwater potential zone map, generated through weighted overlay analysis of ten thematic layers, categorized the basin into excellent (1.39%), very good (17.9%), good (79.17%), and low (1.54%) potential zones. Most wells align with high-potential zones, confirming predictive accuracy: 74% of Wells are in very good zones and 26% in good zones, with none in low-potential areas. Transmissivity (T) in the study area varies from 0.05 to 841.10 m²/day, indicating a heterogeneous aquifer system. Moderate to moderately high transmissivity zones (59.77–89.93 m²/day) dominate, covering nearly 60% of the area, mainly in the central and northern parts, suggesting good aquifer productivity. Geophysical investigations identify Layer 6 (highly weathered and fractured pyroclastic rocks) as the most promising aquifer, followed by Layers 5 and 4, while upper shallow layers function as aquitards. A strong correlation between transmissivity and transverse resistance (r = 0.83, p = 1.32×10⁻¹³) supports the integration of geophysical and pumping test data for aquifer assessment. Well yield discrepancies in the UBRB are influenced more by drilling challenges than by aquifer natural heterogeneity. An analysis of 220 Wells indicates a partial penetration ratio (L/b) of 0.13 to 0.96, with a mean of 0.56, suggesting moderately penetrating wells. Wellbore storage shows that 49% of wells have high storage (Cw ≥ 0.9), while 27% have low storage (Cw < 0.1), reflecting variable aquifer connectivity. In a study of 25 wells, loss coefficients (C) range from 4.0×10⁻⁷ to 5.0×10⁻⁵ day²/m⁵, with 72% classified as severely clogged and none being properly developed. Well efficiency varies between 11.2% to 100% (mean 70.3%), with 18% rated Poor, 22% Fair, 30% Good, and 30% Excellent. This highlights the need for better well design, development, and maintenance practices. The correlation between transmissivity and well efficiency demonstrates that aquifer transmissivity primarily governs well performance, with high-transmissivity zones hosting the most efficient wells. In contrast, low efficiency in moderately transmissive areas mainly stems from technical issues—such as improper well design, partial penetration, or excessive wellbore storage rather than aquifer limitations. Enhancing well construction and maintenance practices is therefore crucial to fully realize groundwater potential in these zones.