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Item Malachite green and methylene blue dye removal using modified bagasse fly ash: Adsorption optimization studies(Elsevier BV, 2024) Meskel, Azeb Gebre; Kwikima, Muhajir Mussa; Meshesha, Beteley Tekola; Habtu, Nigus Gabbiye; Naik, S.V. Chinna Swami; Vellanki, Bhanu PrakashUtilizing Bagasse Fly Ash (BFA) as an adsorbent, a byproduct from the sugar industry, proved effective in removing a mixture of Malachite Green and Methylene Blue dyes from aqueous solutions. To enhance its efficacy, the fly ash underwent chemical modification and underwent detailed characterization using FTIR, XRD, SEM, and TGA analyses. Subsequently, adsorption studies were conducted to optimize critical parameters—initial dye concentration, contact time, and pH levels—employing a Mixed-Level Factorial design to pinpoint the most favorable conditions for efficient dye removal. The modified Bagasse Fly Ash (BFA) resulted in a maximum adsorption capacity of 18.75 mg/g (71.5 %) for Malachite Green and 15.5 mg/g (67.2 %) for Methylene Blue at initial dye concentration of 100 mg/L, pH of 9.6, and time of 51.5 min. Analysis of the sorption data involved rigorous application of both Langmuir and Freundlich isotherm models, revealing a strong fit of the linear representation to the data for both dyes. Specifically, R2 values of 0.97 and 0.93 were observed for Malachite Green, while notably higher values of 0.99 and 0.96 were obtained for Methylene Blue, affirming an excellent model-data agreement. Additionally, a kinetic study revealed that the dye adsorption process (MB and MG) followed the pseudo-second-order kinetic model (R2 > 0.99), indicating that chemisorption as dominant adsorption mechanism and providing valuable insights into the dynamic behavior of the process.Item Assessment of soil quality along river Ng'ombe impacted by battery recycling factory at Ubungo in Dar-es-Salaam(Elsevier BV, 2023) Kwikima, Muhajir Mussa; Mhagama, Aloyce M.Urban soils and streams contaminated with heavy metals have grown ubiquitous around the world throughout the industrialization age, severely reducing the quality and diversity of life. Industrial waste, such as chemicalreleasing factories, is one of the primary anthropogenic sources of heavy metal contamination in soil and water bodies. To analyze the impact of industries to heavy metal contamination, the study assessed the soil quality along the heavy metals polluted river Ng’ombe near the battery recycling plant in Dar es Salaam, Tanzania’s commercial city. The research looked at three heavy metals (Cu, Pb, and Zn) in a total of eight samples. Soils were found contaminated with both metals i.e., Copper, Lead, and Zinc at 4.68, 4.08 mg/L and, 5.79, respectively. Based on the soil samples taken surrounding the industry, it is possible to establish that the industry contributes significantly to the contamination in the soil and river Ng’ombe stream. Pb contamination was found to be fairly equally distributed across the area (2 to 6 mg/kg), as opposed to Zn (0.8 to 17 mg/kg) and Cu (0.04 to 19 mg/kg), which were shown to vary greatly on soil samples obtained around the area. Different pollution indices including geo-accumulation index, Potential contamination index, Contamination factor, Pollution load index and Modified degree of contamination were also used to investigate the impact of soil contamination, and all of them revealed that industrial discharges were an influence. However; study found the levels to be in permissible limit, but still, it exposes the community to cumulative consequences of metals bioaccumulation.Item Biofilm-Enhanced Natural Zeolite Material in Purification Performance for Slaughterhouse Wastewater(MDPI AG, 2023) Mkilima, Timoth; Meiramkulova, Kulyash; Kydyrbekova, Aliya; Bazarbayeva, Tursynkul; Gulnur, Daldabayeva; Aknur, Zholdasbek; Shegenbayev, Abzal; Nurbolat, Dzhexenbayev; Oshanova, Gulaina; Gulzhakhan, KaisagaliyevaThis study focuses on evaluating the efficacy of biofilm-enhanced natural zeolite for the purification of slaughterhouse wastewater. The investigation encompasses four distinct treatment methods: employing natural zeolite without biofilm, integrating biofilm into 1–2 mm particle size natural zeolite, enhancing biofilm in less than 4 mm particle size natural zeolite, and introducing biofilm in less than 8 mm particle size natural zeolite. The outcomes underscore the substantial improvement brought about by biofilm incorporation. For instance, within the natural zeolite treatment system without biofilm, the final effluent retained 28 NTU of turbidity. In contrast, utilizing the <8 mm particle size with biofilm resulted in 3.2 NTU of turbidity in the treated effluent, 2.45 NTU for the <4 mm particle size with biofilm, and 1.02 NTU for the 1–2 mm particle size zeolite system with biofilm. Notably, the achieved removal rates were significant, reaching 79.88% for natural zeolite without biofilm, 97.69% for the <8 mm particle size with biofilm, 99.27% for the <4 mm particle size with biofilm, and 98.24% for the 1–2 mm particle size zeolite system with biofilm. It is noteworthy that the removal efficiencies varied from 50 to 100% for wastewater samples subjected to the treatment system without biofilm, 65.7–100% with the <8 mm particle size biofilm, 71.4–100% with the <4 mm particle size biofilm, and 71.7–100% with the 1–2 mm particle size zeolite system biofilm. These findings collectively emphasize the pivotal role of biofilm in enhancing treatment outcomes, presenting a promising avenue for optimizing wastewater treatment efficiency.Item Delving into Earth Dam Dynamics: Exploring the Impact of Inner Impervious Core and Toe Drain Arrangement on Seepage and Factor of Safety during Rapid Drawdown Scenarios(MDPI AG, 2023) Utepov, Yelbek Bakhitovich; Mkilima, Timoth; Aldungarova, Aliya Kairatovna; Shakhmov, Zhanbolat Anuarbekovich; Akhazhanov, Sungat Berkinovich; Saktaganova, Nargul Amanovna; Abdikerova, Uliya Baktybaevna; Budikova, Aigul MoldashevnaThe study examined the intricate relationships between embankment slope configurations, toe drain designs, and drawdown scenarios. It utilized a unique combination of numerical, physical, and mathematical models. The investigation involved 16 numerical models and 8 physical models with distinct characteristics. The research explored the correlations of key parameters: matric suction, horizontal water conductivity, time, and factor of safety. The factor of safety values varied from 0.62 to 1.03 as a result of the different investigated combinations. For instance, a 1:2 embankment slope without a toe drain under instantaneous drawdown led to the factor of safety values ranging from 1.22 to 1.57. Additionally, incorporating elements like a 30 m toe drain and a 1 m per day drawdown rate influenced these values, with extremes recorded from 1.337 to 2.21, shedding light on embankment stability under diverse conditions and configurations. When subjected to a 1 m per day drawdown, water flow rates decreased significantly at the upstream face and increased downstream, accompanied by an increase in water mass flux at the upstream face and a decrease at the downstream toe, suggesting dynamic changes in water behavior in response to drawdown. Moreover, the findings unveiled significant correlations between matric suction and time (correlation coefficient of 0.950) and factor of safety and water conductivity (correlation coefficient of 0.750). Conversely, a distinct negative correlation emerged between matric suction and factor of safety (correlation coefficient of −0.864). The study’s distinctive insights contribute to our understanding of seepage behavior and dam stability across varied scenarios, offering valuable input for resilient dam construction approaches that will ensure the longevity and effectiveness of these essential structures.Item Assessment of Water Regime, Management and Quality Analysis Based on Water Quality Indices – A Case of Karaganda Region, Kazakhstan(HARD Publishing Company, 2023) Pangaliyev, Yerbol; Akbayeva, Lyailya; Mamytova, Nurgul; Shamshedenova, Samal; Onerkhan, Gulzhaina; Mkilima, TimothThe research aims to analyze the complex water balance, surface water quality, and water resources management in the Karaganda region. A thorough investigation involved examining 119 lakes and 12 rivers within the region. The study revealed that the annual river flow into the Karaganda lakes and their subsequent outflow from the territory was notably meager, accounting for only 0.935% and 3.031%, respectively, primarily due to the scarcity of water bodies in the region. As for water quality, none of the lakes qualify as “highly suitable water” (>50), necessitating further treatment to make them drinkable. Only a small fraction, 4.6% of the lakes, display water quality scores ranging from 50 to 100, indicating the urgent need for substantial remediation efforts. Additionally, a considerable proportion, 47.7% of the lakes, fell within the water quality range of 100-200, demanding treatment before appropriate use. Furthermore, a noteworthy 11% of the lakes were deemed “unsuitable for drinking” (>300), while 36.7% are classified as “very poor water” in the range of 200-300. In the context of Integrated Water ResourcesItem GIS-based analysis of landslides susceptibility mapping: a case study of Lushoto district, north-eastern Tanzania(Springer Science and Business Media LLC, 2023) Makonyo, Michael; Zahor, ZahorLandslides are becoming increasingly widespread, claiming tens of thousands of fatalities, hundreds of thousands of injuries, and billions of dollars in economic losses each year. Thus, studies for geographically locating landslides, vulnerable areas have been increasingly relevant in recent decades. This research is aimed at integrating Geographical Information Systems (GIS) and Remote Sensing (RS) techniques to delineate landslides susceptibility areas of Lushoto district, Tanzania. RS assisted in providing remote datasets including; Digital Elevation Models (DEMs), Landsat 8 OLI imageries, and past spatially distributed landslides coordinate with the use of a handheld Global Position System (GPS) receiver, while various GIS analysis techniques were used in the preparation and analysis of landslides influencing factors hence, generating landslides susceptibility areas index values. However, rainfall, slope angle, elevation, soil type, lithology, proximity to roads, rivers, faults, and Normalized Difference Vegetation Index (NDVI) factors were found to have a direct influence on the occurrence of landslides in the study area. These factors were evaluated, weighted, and ranked using Analytical Hierarchy Process (AHP) technique in which a 0.086 (8.6%) Consistency Ratio (CR) was attained (highly accepted). Findings reveal that rainfall (29.97%), slopes’ angle (21.72%), elevation (15.68%), and soil types (11.77%) were found to have high influence on the occurrence of landslides, while proximity to faults (8.35%), lithology (4.94%), proximity to roads (3.41%), rivers (2.48%), and NDVI (1.69%) had very low influences, respectively. The overall results, obtained through Weighted Linear Combination (WLC) analysis techniques indicate that about 97669.65 Hectares (ha) of land are under very low levels of landslides susceptibility, which accounts for 24.03% of the total study area. Low susceptibility levels had 123105.84 ha (30.28%), moderate landslides susceptibility areas were found to have 140264.79 ha (34.50%), while high and very high susceptibility areas were found to cover about 45423.43 ha (11.17%) and 57.78 ha (0.01%), respectively. Furthermore, 81% overall model accuracy was obtained as computed from the Area Under the Curve (AUC) using Receiver Operating Characteristic (ROC) curve.Item Impact of Xiaolangdi Reservoir on the Evolution of Water Infiltration Influence Zones of the Secondary Perched Reach of the Lower Yellow River(MDPI AG, 2023) Zhang, Min; Ping, Jianhua; Zou, Yafei; Li, He; Mahwa, Joshua; Zhao, Jichang; Liu, JiaqiUnderstanding the complex interplay between water management infrastructure and groundwater dynamics is crucial for sustainable resource utilization. This study investigates water infiltration dynamics in the secondary perched reach of the Yellow River after the operation of the Xiaolangdi Reservoir. The methodology included the application of the single-factor analysis of variance and water balance method, alongside a dual-structure, one-dimensional seepage model to simulate interactions within the system, while exploring characteristics of the groundwater flow system and the exploitation depth of below 100 m. Furthermore, we studied the influence zone range and alterations in river water infiltration in the secondary perched reach of the river following the operation of Xiaolangdi Reservoir. The results show that before the operation of the reservoir, the influence ranges of the north and south banks of the aboveground reach extended from 20.13 km to 20.48 km and 15.85 km to 16.13 km, respectively. Following the initiation of the reservoir, the river channel underwent scouring, leading to enhanced riverbed permeability. Additionally, the influence of long-term groundwater exploitation on both riverbanks extended the influence range of groundwater recharge within the secondary perched reach of the river. The influence zone of the north bank is now 23.41 km–26.74 km and the south bank 18.43 km–21.05 km. After years of shallow groundwater extraction, multiple groundwater depression cones emerged within the five major groundwater source areas on both sides of the river. Notably, deeper water levels (Zhengzhou to Kaifeng) have significantly decreased, with a drop of 42 m to 20 m to 15 m. This change in groundwater dynamics extended beyond the main channel of the river, creating a localized shallow groundwater field.Item Modelling Local Demand and Locational Configuration in Floating Catchment Area Measures of Spatial Accessibility(International Journal of Environment and Geoinformatics, 2023) MAHUVE, Frank; TARIMO, BeatriceThe modelling of catchment-based instead of local demand and optimal instead of sub-optimal character (i.e., locational configuration) of service delivery systems, commonly done in Floating Catchment Area (FCA) measures, generate spatial accessibility indices that might be misleading. The ability of recent FCA measures, three-step (3S) FCA, Modified (M) two-step (2S) FCA, and Balanced (B) FCA to capture local demand and locational configuration was examined in hypothetical systems and Rural Wards of Dodoma Urban District and found to be less appealing. The resulting 3SFCA, M2SFCA, and BFCA spatial accessibility indices inconsistently varied with the local demand or locational configuration. Thus, the study proposed a Modified (M) 3SFCA measure to effectively capture local demand and locational configuration. The proposed M3SFCA measure was implemented in hypothetical systems and Rural Wards of Dodoma Urban District and found to generate spatial accessibility indices that logically varied with local demand and locational configuration. The service users (or households) with low local demand or closer to service providers (or water points) are characterized by higher spatial accessibility indices and vice versa. This characterization of spatial accessibility indices is more realistic and essential for effective monitoring of progress made on the global and national development goals.Item Analysis of methods used to validate remote sensing and GIS-based groundwater potential maps in the last two decades: A review(Elsevier BV, 2024) Bennett, G.The integration of remote sensing data, machine learning and geographic information system in managing and analysing spatial data helps in generating maps showing groundwater potential. These maps are important tools for aiding stakeholders and decision-makers in groundwater resources to make informed decisions during groundwater development and management; to ensure the reliability of these maps, validation with the field data is conducted. This study analysed 125 scientific articles spanning the period from 2002 to 2023. The results show that around 85% of articles contain validated maps, indicating a significant number of researchers adhere to validate the remote sensing and GIS-based maps with field data, which is crucial in scientific research. However, 15% of articles contain non-validated maps. This is an alarming figure; therefore, journals should be strict in ensuring that validation is adhered to. In the reviewed articles, a total of 10 methods were used to validate groundwater potential maps using various parameters such as well yield, well/spring discharge rate, aquifer transmissivity, well specific capacity, and presence of wells/springs. This study will also add to the knowledge of selecting appropriate methods for validating remote sensing and GIS-based groundwater potential maps. The use of field data reflecting aquifer productivity is more appropriate for validation of groundwater potential maps.Item Co-production of organic oil phase (OP) and adsorption biochar from cashew nut shells: modeling and optimization of intermediate pyrolysis process(Springer Science and Business Media LLC, 2023) Kazawadi, D.; Ntalikwa, J; Kombe, G.Cashew nut shells (CNS) are an underutilized agricultural residue generated in large quantities. The study aimed at modeling and optimizing of intermediate pyrolysis (IP) process using response surface methodology of Box-Bohnken method (RSM-BB). Batch experiments were conducted in a fixed-bed reactor to pyrolyze CNS at various particle sizes (1–10 mm), residence times (20–60 min), heating rates (1–10 °C/min), and temperatures (400–600 °C). Ten responses were modeled and optimized to co-produce adsorption carbon and OP as fuel. Co-production occurred at 1–1.7-mm particle size, 22-min residence time, 2.03 °C/min heating rate, and 470 °C temperature. The above optimal parameters gave the yields of biochar, bio-oil, OP, and gas to be 36.52%, 40.9%, 27.8%, and 22.6%, respectively. The analysis of OP revealed that it exhibited pH of 4.65, moisture content of 2.68%, heating value of 26.7 MJ/kg, and density of 1.09 g/cc which were not in the range of values of fossil diesel. Adsorption biochar produced had gold adsorption capacity of 1.86 mgAu/g which was lower than that commercial activated carbon (3–15 mgAu/g). The study demonstrated that IP has potential for valorizing CNS into value-added biochar and OP.Item Exploring the potential of biofunctionalized agricultural waste adsorbents integrated with UV-LED disinfection for enhanced wastewater treatment(Elsevier BV, 2024) Timoth Mkilima; Yerlan Sabitov; Zhanbolat Shakhmov; Talgat Abilmazhenov; Askar Tlegenov; Atogali Jumabayev; Agzhaik Turashev; Zhanar Kaliyeva; Laura UtepbergenovaAgricultural waste holds promise as an adsorbent in wastewater treatment; however, its potential remains understudied, particularly regarding biofunctionalized grape pomace, coffee husks, and corn cobs for carwash wastewater treatment, along with their integration with solar-powered UV-LED disinfection. This study explores the effectiveness of these bio-functionalized adsorbents in wastewater treatment, revealing grape pomace’s high efficacy in removing lead (95.2%), fluorides (94.4%), and nitrates (94.8%), while corn cobs and coffee husks showed significant removal efficiencies for zinc (88.5% and 95.5%, respectively) and cyanides (84.8% and 89.6%, respectively). Grape pomace exhibited a maximum adsorption capacity (qmax) of 162.6 mg/g for lead ions, while coffee husks had the highest qmax of 182.82 mg/g. Kinetic analysis indicated corn cobs’ slower initial adsorption capacity and moderate adsorption rate, contrasting with grape pomace and coffee husks. Furthermore, treatment with these adsorbents, followed by UV-LED disinfection, substantially reduced microbial counts in treated water, underscoring their potential in ensuring water safety. The integration of biofunctionalized adsorbents with UV-LED disinfection presents a promising approach for sustainable and efficient wastewater treatment, with implications for water quality improvement and public health protection.Item Electrode material impact on microbial fuel cell and electro‐Fenton systems for enhanced slaughterhouse wastewater treatment: A comparative study of graphite and titanium(Wiley, 2024-02) Timoth Mkilima; Gulnur Saspugayeva; Zhazgul Tussupova; Gulzhan Kaliyeva; Kulzipa Dakieva; Sanat Kumarbekuly; Zukhra Tungushbayeva; Gulfat KalelovaThe treatment of slaughterhouse wastewater is a complex task demanding careful consideration due to its challenging nature. Therefore, exploring more sustainable treatment methods for this particular type of wastewater is of utmost significance. This research focused on the impact of electrode materials, specifically graphite and titanium, on the efficiency of microbial fuel cells (MFCs) and electro-Fenton systems in treating slaughterhouse wastewater. Both graphite and titanium electrodes displayed increasing current density trends, with titanium outperforming graphite. Titanium showed superior electron transfer and current generation (2.2 to 21.2 mA/m2 ), while graphite ranged from 2.4 to 18.9 mA/m2 . Titanium consistently exhibited higher power density, indicating better efficiency in converting current to power (0.059 to 22.68 mW/m2 ), compared to graphite (0.059 to 12.25 mW/m2 ) over the 48-h period. In removal efficiency within the MFC system alone, titanium exhibited superior performance over graphite in key parameters, including zinc (45.5% vs. 37.19%), total hardness (39.32% vs. 29.4%), and nitrates (66.87% vs. 55.8%). For the electro-Fenton system with a graphite electrode, the removal efficiency ranged from 34.1% to 87.5%, with an average efficiency of approximately 56.2%. This variability underscores fluctuations in the efficacy of the graphite electrode across diverse wastewater treatment scenarios. On the other hand, the electro-Fenton system employing a titanium electrode showed removal efficiency values ranging from 26.53% to 89.99%, with an average efficiency of about 68.4%. The titanium electrode exhibits both a comparatively higher and more consistent removal efficiency across the evaluated scenarios. On the other hand, the integrated system achieved more than 90% removal efficiency from most of the parameters. The study underscores the intricate nature of slaughterhouse wastewater treatment, emphasizing the need for sustainable approaches. PRACTITIONER POINTS: Microbial fuel cell (MFC) and electro-Fenton were investigated for slaughterhouse wastewater treatment. The MFC microbial activity started to decrease after 24 h. The integrated system achieved up to 99.8% removal efficiency (RE) for total coliform bacteria. Up to 99.4% of RE was also achieved for total suspended solids (TSS). The integrated system highly improved RE of the pollutants.Item Exploring the nexus of innovation management, ultraviolet irradiation, and business scale: implications for sustainable fruit and vegetable preservation during the COVID-19 era(Springer Science and Business Media LLC, 2024) Assel Kydyrbekova; Kulyash Meiramkulova; Aliya Kydyrbekova; Timoth MkilimaInnovation management stands as a pivotal driver in attaining enduring sustainability in livelihoods. However, its progress can face formidable obstacles, encompassing the complexities arising from human perceptions. This research delved into the realm of innovation management within the context of fruit and vegetable preservation, with a keen focus on the potential impact of the COVID-19 pandemic and the perceptual evaluations surrounding the viability of utilizing ultraviolet (UV) irradiation for this purpose. The perceived effectiveness of UV irradiation in fruit and vegetable preservation was found to be significantly influenced by factors, such as cost, safety, and limited understanding. The respondents' preference for preserved fruits and vegetables was most significantly influenced by the elimination of pathogenic microorganisms, as indicated by a mean score of 4.6. Notably, around 50.9% of the participants demonstrated a lack of understanding regarding the use of ultraviolet irradiation as a preservation technology. In addition, approximately 21.6% of the respondents expressed disinterest in adopting ultraviolet irradiation for preserving fruits and vegetables. In contrast, a smaller percentage of participants, merely 12.3%, showed a positive inclination towards employing ultraviolet irradiation in the preservation process. Interestingly, approximately 15.2% of respondents remained undecided and did not express a definitive preference concerning their willingness to utilize ultraviolet irradiation for preserving fruits and vegetables. Notably, the analysis has revealed a compelling trend, with a substantial portion of participants (63%) perceiving medium-sized enterprises involved in fruit and vegetable processing technologies as displaying notably low levels of motivation for innovation during the COVID-19 era. A similar viewpoint was shared by 51% of respondents regarding large-scale businesses. In stark contrast, the survey has illuminated a striking disparity, as small-scale businesses exhibited significantly heightened innovation motivation at 28%, surpassing the modest 10% observed in both medium-sized and large-scale counterparts. This pronounced variation in innovation motivation across diverse business scales highlights the multifaceted impact of the pandemic on their inclination towards embracing innovation. These findings offer invaluable insights into the intricacies governing innovation management within the fruit and vegetable preservation sector amidst the challenging COVID-19 period.Item Advancing sanitary surveillance: Innovating a live-feed sewer monitoring framework for effective water level and chamber cover detections(Elsevier BV, 2024) Yelbek Utepov; Alexandr Neftissov; Timoth Mkilima; Zhanbolat Shakhmov; Sungat Akhazhanov; Alizhan Kazkeyev; Assel Toleubekovna Mukhamejanova; Aigul Kenzhebekkyzy KozhasEfficient sanitation system management relies on vigilant sewage surveillance to uphold environmental hygiene. The absence of robust monitoring infrastructure jeopardizes unimpeded conduit flow, leading to floods and contamination. The accumulation of harmful gases in sewer chambers, coupled with tampered lids, compounds sewer network challenges, resulting in structural damage, disruptions, and safety risks from accidents and gas inhalation. Notably, even vehicular transit is vulnerable, facing collisions due to inadequately secured manholes. The core objective of this research was to deconstruct and synthesize a prototype blueprint for a live-feed sewer monitoring framework (LSMF). This involves creating a data gathering nexus (DGN) and empirically assessing diverse wireless sensing implements (WSI) for precision. Simultaneously, a geographic information matrix (GIM) was developed with algorithms to detect sewer surges, blockages, and missing manhole covers. Three scrutinized sensors—the LiDar TF-Luna, laser TOF400 VL53L1X, and ultrasonic JSN-SR04T—were evaluated for their ability to measure water levels in sewer vaults. The results showed that the TF-Luna LiDar sensor performed favorably within the 1.0–5.0 m range, with a standard deviation of 0.44–1.15. The TOF400 laser sensor ranked second, with a more variable standard deviation of up to 104 as obstacle distance increased. In contrast, the JSN-SR04T ultrasonic sensor exhibited lower standard deviation but lacked consistency, maintaining readings of 0.22–0.23 m within the 2.0–5.0 m span. The insights from this study provide valuable guidance for sustainable solutions to sewer surveillance challenges. Moreover, employing a logarithmic function, TF-Luna Benewake exhibited reliability at approximately 84.5%, while TOF400 VL53L1X adopted an exponential equation, boasting reliability approaching approximately 89.6%. With this navigational tool, TF-Luna Benewake maintained accuracy within ±10 cm for distances ranging from 8 to 10 m, showcasing its exceptional performance.Item Harnessing graphene oxide-enhanced composite metal-organic frameworks for efficient wastewater treatment(Elsevier BV, 2024) Timoth Mkilima; Yerkebulan Zharkenov; Laura Utepbergenova; Aisulu Abduova; Nursulu Sarypbekova; Elmira Smagulova; Gulnara Abdukalikova; Fazylov Kamidulla; Iliyas ZhumadilovThe issue of carwash wastewater emerges as a pressing environmental concern on a global scale, primarily due to the intricate nature of its pollutants, which makes effective treatment a formidable challenge. In the face of this complex scenario, the pursuit of an efficient treatment methodology assumes paramount importance. In response to this complex scenario, this study embarked on an exploration of a novel polymeric adsorbent material synthesized from Zeolitic Imidazolate Framework-67, Zeolitic Imidazolate Framework-8, Polyethersulfone, and graphene oxide in a fixed-bed treatment system for carwash wastewater. The investigation encompassed three distinct filter column depths, measuring 8 cm, 12 cm, and 16 cm, respectively. With an increase in filter depth from 8 cm to 16 cm, notable improvements were observed in the removal efficiencies for most contaminants. Notably, oils/grease removal showed an increasing trend with column depth, reaching 95.4%, 98.6%, and 100% for 8 cm, 12 cm, and 16 cm depths, respectively. TSS and Turbidity removal efficiencies remained consistently high at 100% across all depths, showcasing effective removal of solid particulate matter. Copper and Zinc removal efficiencies increased with deeper column depths, reaching values of 80.4%–89.9% and 79.6%–90.3%, respectively. Surfactants exhibited efficient removal, with values ranging from 90.6% to 96.6%. Total Dissolved Solids removal efficiency increased from 71.6% to 83.4% as column depth increased. Similarly, Chemical Oxygen Demand, Biochemical Oxygen Demand, total organic carbon, and phosphates removal efficiencies showed improvement with increasing column depth, reaching values of 95.4%, 98.3%, 98.8%, and 89.3%, respectively. Moreover, The composite MOF beads demonstrated significant adsorption capacities in carwash wastewater treatment, with a noteworthy 35.08 mg/g for Oils/Grease and 28.12 mg/g for Biochemical Oxygen Demand, highlighting their efficiency in removing hydrophobic contaminants and organic pollutants.The derived results highlight the potential of the composite material for carwash wastewater treatment towards advancing the field of wastewater treatment.Item Hydrogeochemical characterization of the groundwater in northern and eastern areas of Kilwa district and Songosongo Island in, Tanzania(Wiley, 2024) Asantael Herman Mlay; Ceven Shemsanga; George Bennett; Justin NtalikwaThis study aimed to investigate the hydrochemical and hydrogeochemical facies and mechanisms controlling groundwater quality from the northern and eastern parts of Kilwa district and Songosongo Island in Tanzania. Multifaceted methods were used to analyze the hydrochemical properties of water in relation to local geology and proximity to the Indian Ocean. The pH of the groundwater ranged from 5.18 to 7.56 with an average value of 6.64 which is slightly acidic. Electrical Conductivity (EC) ranged from 354 to 1429.50 μS/cm with an average value of 1652.6 μS/cm while Total Dissolved Solids (TDS) values varied from 170 to 1825 mg/L with an average value of 918.8 mg/L. The average values for Ca2+, Mg2+, Na+, and K+ were 36.9, 21.4, 152.5, and 13.31 mg/L, while for NO3−, Cl−, HCO3−, and SO42- were 2.1, 256.3, 156.6, and 45.8, respectively. The study found that groundwater closest to the ocean had elevated values of TDS, Na+, and Cl− and were more affected by seawater intrusion compared to those further inland. The dominant groundwater type was established to be Na-Cl mostly nearest to the ocean while Ca-Mg-Cl was more encountered towards the inland. The groundwater in the northern and eastern parts of Kilwa is mainly controlled by seawater intrusion and recharge water. The Neogene formations consisting of clay, silts, coastal sands, and alluvium had lower Na+, Cl−, EC, and TDS values than the Paleogene which is more influenced by marine sediments. Thus, these findings call for improved groundwater monitoring to track changes in water quality since several parameters including sodium, magnesium, chlorides, TDS, EC, and pH were higher than recommended values for drinking purposes. However, the majority of the water samples were suitable for human consumption.Item Mining and sustainable development goals in Africa(Elsevier, 2024-03) Mvile, Benatus Norbert; Bishoge, Obadia KyetuzaEvery country seeks to assure development that satisfies the requirements of the current generation without jeopardising the ability of future generations to meet their own needs. This concept was proposed in the World Commission on Environment and Development’s report, Our Common Future as Sustainable Development (SD). All United Nations members adopted the seventeen goals in 2015 to accomplish the SD. These goals are referred to as sustainable development goals (SDGs) and include 169 targets that must be met by all countries by 2030. The mining sector is critical to achieving the SDGs. While Africa is endowed with much mineral wealth potential for achieving SDGs by 2030, most of these countries are facing the problem of the “resource curse” together with other socioeconomic, environmental, and political challenges, such as civil war and extreme poverty. This review examines pertinent past and current studies to provide an overview of the relationship between the mining sector and SDGs in Africa. Relevant data and information were collected, selected, evaluated, interpreted, and presented in themes, graphs, and tables from diverse bibliographic sources, such as the Web of Sciences, Google Scholar, and grey literature. This study revealed that mining does not involve a single primary point of interaction with a single SDG. Instead, it contributes to multiple goals at the same time. This is because mining operations and businesses have numerous beneficial and negative effects on communities, ecosystems, and economies. It contributes to eliminating extreme poverty, reducing hunger, and improving human health and education in communities. It generates foreign revenue and creates jobs, allowing governments to enhance their socioeconomic infrastructure. However, the mining industry is still overwhelmingly male-dominated, and contributes to environmental problems such as climate change and other social constraints such as political instability.Item Optimization of solvothermal liquefaction of water hyacinth over PTFE-acid mediated kaolin catalyst for enhanced biocrude production(Elsevier BV, 2024) Ishaq Kariim; Ramadhani Bakari; Yusuf Olatunji Waidi; Wajahat Waheed Kazmi; Sunita Kumari Malla; Ji-Yeon Park; Muhammad Wasi Syed; Ali Hassan Bhatti; Ahmed Omer; Hulda Swai; In-Gu Lee; Thomas KiveveleThe invasive nature of water hyacinth and the need for renewable energy sources have necessitated this research. Catalyst development through enhanced pore structure and process parameters optimization are requirements for effective mass transport during the biomass valorization and improved biocrude formation during solvothermal liquefaction process. In this present study, the effects of temperature (250–340 ◦C), residence time (10–20 min) and catalyst loading (10–13 wt%) on biocrude, biochar, gas yield, and biomass conversion were optimized using a Box-Behnken experimental design. The developed catalyst through the application of polytetrafluoroethylene (PTFE) for pore structure enhancement was characterized using SEM, BET and XRD techniques. The process optimization found maximum biocrude yield (32.0 wt%), minimum biochar yield (19.4 wt%) and maximum conversion efficiency (80.6%) at 340 ◦C, 20 min residence time, and 13 wt% catalyst loading. The GC-MS result of the biocrude produced at the optimum conditions (13 wt% catalyst loading) consists of ketones (32.2%), acids (22.3%) and had 65.2% carbon, 7.3% hydrogen, HHV of 29.4 MJ/kg and H/C ratio of 1.34 while an increment in catalyst loading of 20 wt% enhanced the overall biocrude properties with HHV of 35.50 MJ/kg. This result depicts the suitability of the PTFE modified acid treated kaolin for high quality biocrude production through valorization of water hyacinth into a candidate for renewable energy material.Item Analysis of methods used to validate remote sensing and GIS-based groundwater potential maps in the last two decades: A review(Elsevier BV, 2024) Bennett, G.The integration of remote sensing data, machine learning and geographic information system in managing and analysing spatial data helps in generating maps showing groundwater potential. These maps are important tools for aiding stakeholders and decision-makers in groundwater resources to make informed decisions during groundwater development and management; to ensure the reliability of these maps, validation with the field data is conducted. This study analysed 125 scientific articles spanning the period from 2002 to 2023. The results show that around 85% of articles contain validated maps, indicating a significant number of researchers adhere to validate the remote sensing and GIS-based maps with field data, which is crucial in scientific research. However, 15% of articles contain non-validated maps. This is an alarming figure; therefore, journals should be strict in ensuring that validation is adhered to. In the reviewed articles, a total of 10 methods were used to validate groundwater potential maps using various parameters such as well yield, well/spring discharge rate, aquifer transmissivity, well specific capacity, and presence of wells/springs. This study will also add to the knowledge of selecting appropriate methods for validating remote sensing and GIS-based groundwater potential maps. The use of field data reflecting aquifer productivity is more appropriate for validation of groundwater potential mapsItem Estimation of groundwater recharge from groundwater level fluctuations and baseflow rates around Mount Meru, Tanzania(Elsevier BV, 2024) Bennett, G.; Shemsanga, C.; Kervyn, M.; Walraevens, K.Estimating groundwater recharge, direct runoff and baseflow is essential for understanding groundwater resource availability and managing groundwater systems. This study estimates groundwater recharge, direct runoff and baseflow on two slopes of Mount Meru: the northern and southern slopes using the water-table fluctuation (WTF) method and baseflow separation technique. High-frequency groundwater level measurements in five shallow wells over three hydrological years from 2018 to 2021 were analysed, while streamflow data in four gauging stations over nine hydrological years from 2010 to 2019 were used. The results of the WTF method show that the aquifer undergoes an average recharge of 544 mm/year and 90 mm/year on the south western and north-eastern slopes, respectively. On average, this recharge is about 53% and 13% of the annual rainfall on each slope. The baseflow results show that the aquifer on the south-eastern and north-western slopes recharges an average of 88 mm/year and 54 mm/year, respectively, which is on average about 12% and 7% of annual rainfall, respectively. In general, the high recharge on the south-western slope is attributed to the high rainfall, and the high hydraulic conductivity and high hydraulic diffusivity of the pyroclastic deposits compared to the debris avalanche deposits on the north-eastern slope. In addition, debris avalanche deposits show homogeneous recharge conditions, while pyroclastic deposits show heterogeneous recharge conditions. The WTF method can be useful to identify areas of preferential recharge so that preferential groundwater flow paths can be mapped for focused recharge of surface runoff during the rainy season.