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Abstract Anthropogenic and hydrogeological factors are detrimental factors on the then brine lake, Beseka. The lake is in a state of dramatic change in its nature. The aim of this systematic review is to identify knowledge gaps related to the change in water quality and its suitability for different uses. The study also assesses trends in Lake Beseka's (LB) water quality. Previously, it was believed that volcanic lakes were harmful to the environment and unusable for the welfare of humans, animals, and other living things. However, LB in Ethiopia is a special or uncommon case to leave doubt to this general believes. This assessment shows the rapid transformation of the lake’s waters to safer and usable one from its brine form. To evaluate the water quality of Lake Beseka, various parameters and techniques (indices) can be used. Between 1961 and 2021, the lake’s salinity decreased from 74100 to 2520 µS/cm (1,654 µS/cm in April, 2024). Other important Water Quality Index parameters that show sharp decline can be mentioned. Sodium content declined from 17,800 to 630 mg/L, chlorides declined from 5480 to 210 mg/L, and sulfates, declined from 4680 to 192 mg/L. Eutrophication-related lake issues are being evaluated. Large-scale water quality parameters demonstrate rapid alterations brought on by freshwater discharge into lakes, which may shed light on their use for livestock and crop production. Although it is not currently advised for use, it has demonstrated an unpredicted dilution trend and is getting close to the FAO standards. It is crucial to take into account options to lessen the effects of the adjacent Awash River by upgrading infrastructure and changing the lake's natural flow in order to address the issues with average water quantity. As a result, the Lake Beseka water source will continue to be a useful resource for many years to come. This study suggests that volcanic lakes, such as Lake Beseka, may be crucial in addressing future water security issues in the basin.

Background: An essential component of environmental sustainability and sanitation is the management of dry toilets, especially waste disposal. Understanding the composition of the brown water from dry toilets, putting the proper composting technique in place, and guaranteeing safe disposal and reuse procedures are all necessary to handle the waste successfully. It has been discovered that brown water, sometimes known as feces, can be used for brick-making, fuel, fertilizer, and other purposes. Methods: This review focuses on dry toilet technology, management processes, and sanitation systems in Ethiopia and other underdeveloped nations. It utilizes secondary information and searches from Google scholars, Library catalogs, and Researchers to comprehend dry sanitation systems, including their implementation, use, and maintenance. Keywords used in the search include “in-situ treatment,” “fecal sludge treatment,” “fecal slurry management,” and “brown water treatment.” Results: The review used a total of 108 articles and books, agricultural research, and reports on the feces’ physical, chemical, and biological characteristics. It also discussed risks associated with the mismanagement of feces, including parasitic diseases in exposed humans. The main aim of the review was to develop an understanding of brown water uses, composition, and management and select the proper method of composting with dry toilets. Conclusion: Dry toilets in developing countries are utilized for ecological sanitation and agriculture, with feces potentially used as fertilizer. Utilizing feces as fertilizer is a sustainable, eco-friendly, and environmentally responsible practice that can increase productivity while maintaining a clean environment.

Abstract Visible‐light active anatase/brookite/rutile (A/B/R) ternary N‐doped titania (N/TiO2) crystals are successfully prepared by a facile sol‐gel method using titanium butoxide and benign N‐dopant source, guanidinium chloride. Systematically varying the aging time (1, 4, 8, and 12 d), its influence on physicochemical properties of as‐obtained spherical heterojunction nanomaterials is studied. Detailed characterizations confirm that a substantial amount of anatase (88% to 50%) is transformed to rutile (2% to 38%) via intermediate brookite phase (9% to 25%) as the function of aging time; not only the A/B/R phase content of the samples is tuned by sol‐gel aging time of the precursors solution but also their optical‐response and methylene blue photocatalytic properties are profoundly dictated. Notably under visible‐light irradiation, the photostable rutile rich mesoporous A/B/R triphasic N/TiO2 (50% A, 12% B, 38% R) aged for 12 d demonstrates higher degradation activity (97%) with a faster degradation rate (0.033 min−1) than both lesser aged N/TiO2 and undoped titania. This enhancement is attributed to the synergistic effect of interstitial‐N‐doping and optimal A/B/R interfacial charge transfer that leads to higher light absorption, lower bandgap energy and well‐separated charge carriers. The current work provides a new perspective for designing highly active visible‐light heterostructure nanomaterials with controllable phase composition.

Road traffic accidents (RTAs) and the resulting traffic congestion are global concerns mainly in metropolitan environments. The need for road safety is directly correlated with the rapidly increasing impact of urbanization on infrastructure and day-to-day living. In this study, we have introduced an innovative approach integrating a Random Forest (RF) model, crash rates, and spatial network analysis to provide safe route recommendations for drivers aiming to reduce RTAs and congestion. Based on historical accident data from 2014–2019, the analysis of the RF model and crash rate served as a prediction of the likelihood and occurrence of RTAs. In applying the spatial network analysis, lower predicted crash counts from spatial joining were taken into consideration, as well as areas with lower crash rates that have had fewer incidents in the past. An alternative safe route and an optimum route that covers 32.27 km in 50.78 mins of travel time and 28.6 km in 41.58 mins of travel time were successfully identified, respectively. Having demonstrated 78 % predictive capability on the target variable, the RF model has proved its worth. Analyzing historically lower accident counts on segments leading to minimal crash rates validates the accuracy of the identified safe route. This advanced method significantly aids in improving traffic safety by making drivers and travelers aware of potentially high rates of accidents and traffic congestion on road segments. It assists travelers with their trip planning to anticipate potential risks and suggest safer alternate routes, making it a valuable contribution to the field.

In this investigation, several electrochemical and advanced oxidation processes (AOPs), including photolysis (UV), direct/alternating current-electrocoagulation (DC/AC/EleC), and photo-direct/alternating current-electrocoagulation (UV/DC/AC/EleC) process were examined regarding their capacity in order to reduce the amount of chemical oxygen demand (COD) and color in distillery industrial wastewater (DIW), as well as the effect these factors have on the amount of electricity required to treat the wastewater. Experimental results showed that compared to single UV, DC/EleC, AC/EleC, and hybrid UV/DC/EleC processes, the hybrid UV/AC/EleC process provided excellent color-100 % and COD-100 % removal efficiencies with a lowered usage of energy of 8.54 kWhr m−3. The influence of critical operational variables such as treatment time (30–240 min), photo (8–40 W), pulse duty cycle (0.14–0.86), current (0.15–0.90 Amp), pH (1.50–11.50), chemical oxygen demand (3000–9000 mgL−1), inter electrode spacing (1–4 cm), electrode combination (Fe/Fe, Fe/Al,Al/Fe, Al/Al), and electrolyte concentration (1–5 g L−1) on the efficiency of% color and COD removal, as well as the energy utilization of DIW were examined applying a hybrid UV/AC/EleC method. The synergistic index between UV and the AC/EleC process was also examined and discussed in this work. The UV/AC/EleC technique is the most advantageous choice in comparison to the other approaches since it can be applied to properly and efficiently remove pollutants from wastewater and industrial effluent.

A magnetite-diatomite nanocomposite (MDM) adsorbent was synthesized using the co-precipitation method, wherein a magnetite precursor was intercalated into diatomite clay minerals sourced from the Ethiopian Rift Valley. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy energy dispersive x-ray (SEM-EDX), Brunauer-Emmett-Teller (BET) and magnetometry measurements were used to look into the structure and magnetic properties of the adsorbent. Batch experiments were conducted to study the remarkable Cd (II) adsorption capacity of MDM and the ease of separating the used adsorbent with a bar magnet. The most important adsorption parameters, namely, initial pH, adsorbent dose (g), initial (Cd (II) concentration (mg), and contact time (min), were optimized using Box-Behnken design (BBD). The MDM has shown exceptional Cd (II) removal under optimum conditions, with a maximum adsorption capacity of 31.4 mg/g from aqueous solution. Based on the results of isotherm and kinetic studies, the Temkin and pseudo-second-order models were found to provide the most accurate fit for adsorption equilibrium when compared to the alternative models. The thermodynamic studies, under standard conditions revealed that, Cd (II) uptake is exothermic and spontaneous. The finding of this study confirms that the MDM adsorbent is easily reusable, extractable from the solution using an external magnet, and capable of recovering around 80 % of Cd (II) when HNO3 is used as a desorbing agent. The study demonstrates a cost-effective and environmentally friendly approach to remediate Cd (II) pollution in wastewater. Furthermore, the superior Cd (II) adsorption capacity, combined with the ease of separating using a bar magnet and high reusability, highlights the potential of this novel adsorbent as a sustainable and efficient solution for addressing Cd (II) contamination in various wastewater treatment applications.Thereby contributing significantly to advancements in the field of heavy metal removal from aqueous solutions.

The study was focused on preparing activated carbon from one of the predominant agro-wastes, teff straw (TS), through chemical activation and investigating the optimum process condition for removing the reactive yellow 145 dye (RY 145) from simulated textile effluent and chemical oxygen demand (COD) from textile industry effluent. The prepared activated carbon (TSAC) was characterized using Fourier transform infrared (FTIR), scanning electron microscopy (SEM), point of zero charge (pHpzc), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) surface area. Response surface methodology (RSM) was adopted to optimize the process variables. Optimum parameters for the removal of RY 145 dye were contact time, pH, adsorbent dose, and initial dye concentration of 120 min, 2, 0.4 g, and 0.3 g/L, respectively, and 97% removal efficiency was achieved. The experimental data that well-fitted with the pseudo-second-order kinetic model, while examining isotherms, was the Langmuir model. Furthermore, the TSAC reusability study confirmed that TSAC can be used multiple times in dye removal from wastewater. These results suggested that a low-cost and eco-friendly bio-based adsorbent, TSAC, could be a promising and reusable adsorbent that could be an alternative for commercial activated carbon to be applied in polluted wastewater treatment. HIGHLIGHTS RSM was applied to optimize the RY 145 dye adsorption process by TSAC.; TSAC removed 98.71% of the RY 145 dye from simulated textile industrial wastewater.; TSAC removed 81.09% of COD from real textile wastewater.; The adsorption efficiency after the fourth desorption cycle was 89.93%.;

In developing countries like Ethiopia, ensuring the sustainability of water supply systems is a significant challenge. To achieve the Sustainable Development Goal 6 of providing clean water to people worldwide, understanding customer perceptions and satisfaction is crucial. This study conducted questionnaire surveys and interviews with key stakeholders in Adama town to assess customer satisfaction and service quality dimensions. Of 435 participants, 275 (63.22%) were females and 160 (36.78%) were males. The analysis revealed that all dimensions of service quality significantly affected customer satisfaction at a 5% level of significance. Specifically, tangibility, responsiveness, and assurance had a highly significant effect on customer satisfaction (p = 0.001). However, reliability, tangibility, and responsiveness scored below 50% in the overall Customer Satisfaction Index, indicating customer dissatisfaction. On the other hand, assurance and empathy scored above or equal to 50%, suggesting satisfactory levels of customer satisfaction. The study highlighted the importance of addressing Adama's pressure and billing problems to improve the empathy dimension. Enhancing services in these areas would contribute to overall customer satisfaction. The findings of this study are valuable for appropriate municipal service planning and management, facilitating service enhancement and cost recovery efforts. HIGHLIGHTS The overall customer satisfaction index was 41% which implied that the customers were unsatisfied.; Tangibility, responsiveness, and assurance have a highly significant (p-values < 0.001) effect on customer satisfaction.; Female respondents (41%) were more satisfied than males (21%) with AWSSE's services provision.;

Magnetite-diatomite nanocomposite was synthesized through co-precipitation methods as an effective Cr(VI) removal adsorbent. The properties of diatomite, thermochemically modified diatomite (TMD), and magnetic–diatomite nanocomposite (MDN) were investigated using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, Brunauer–Emmett–Teller, and complete silicate chemical analysis. The MDN shows 98.89% adsorption removal at optimized conditions using the response surface methodology of Box–Behnken Design. The kinetic data for Cr(VI) sorption on MDN were well described by pseudo-second order, which indicates the Cr(VI) adsorption was mainly due to chemisorption. The isotherm data show that the Langmuir and Freundlich models better described Cr(VI) ion sorption data. The thermodynamic parameters ΔG°, ΔH°, and ΔS° were estimated, and the results indicate Cr(VI) sorption on MDN was a spontaneous (ΔG° < 0) and exothermic process (ΔH° < 0). The proper Fe3O4 loading into TMD improves the gram susceptibility (Xg) of MDN for magnet separation. The regeneration of nanocomposite material revealed over 80% Cr(VI) removal efficiency after five consecutive adsorption–desorption cycles. The produced MDN was tested for the removal of Cr(VI) from real tannery wastewater. The obtained results suggest the possibility of using this nanocomposite as an effective, efficient adsorbent to remove Cr(VI) laden wastewater. HIGHLIGHTS Easy magnetic recyclable adsorbent.; Efficient Cr(VI) removal adsorbent from Cr(VI) laden tannery effluent.; Easy synthesis and low-cost material.; Highly stable with magnetic reusable potential.; Composite with high electron density and porous material.;

The growing problem of industrial pollution in developing countries, especially Ethiopia, has sparked serious issues about the quality of the water, particularly when it comes to the effluent from wet coffee processing industries. In response, this study investigates the potential of utilizing natural coagulants, Acanthus sennii C., Moringa stenopetala B., and Aloe vera L., either individually or in combination, for the treatment of coffee effluent. Methodologically, the study systematically varies operational parameters, including coagulant dose, pH levels, stirring speed, and stirring time, to evaluate their impact on coagulation efficiency. Experimental data undergo statistical analysis, employing ANOVA, while computational optimization techniques are employed using Design Expert software to determine optimal conditions. Notably, the blended form of the three coagulants emerges as particularly promising, yielding optimal conditions of 0.750 g/L coagulant dosage, pH 8.76, agitation speed of 80.73 rpm, and agitation time of 19.23 min. Under these optimized conditions, the blended coagulant achieves remarkable removal efficiencies, approximately 99.99% for color and 98.7% for turbidity. These findings underscore the efficiency of natural coagulants, particularly in blended form, for sustainable wastewater treatment in wet coffee processing.

Estimating low flow quantiles is essential for regulating minimum flow requirements and ensuring water availability, ecological health, and overall system sustainability. This study aims to quantify regional low flows by analyzing low-flow time series in data-limited environments. We utilized annual minimum 7-day instantaneous streamflow data collected from gaging stations. Discordancy measure assessments revealed that all sites were homogeneous, forming a single region. We employed Easy-Fit Statistical Software to select the best-fit probability distribution model and determine estimation parameter values. Through goodness-of-fit tests (GOFs), the Generalized Pareto model emerged as the most suitable, predicting low flow quantiles for 100-year returns. Rigorous application of GOFs ensures the statistical soundness of the model, capturing underlying data patterns. A correlation coefficient determination (R2) of 0.989 demonstrates the high satisfaction of the selected distribution model. The developed regression line for the region exhibited strong agreement between predicted low flows and catchment area. Thus, accurate estimation proves valuable in environmental and human-influenced decision-making processes, providing insights into low-flow behavior and mitigating drought effects on aquatic ecosystems.

Fluoride is a concern for human health at high concentrations, but it is also a valuable compound with multiple applications. Thus, having a system that gives the opportunity to remove and recover this valuable element from water is highly interesting. Reverse osmosis (RO) is a promising technology in the removal of fluoride from water. Nevertheless, the residual retentate highly concentrated in fluoride is still a concern. The aim of this study was to evaluate the performance of an integrated process consisting of RO and membrane crystallization to remove fluoride from water and to recover it as a pure fluoride salt. Pure water permeability and fluoride rejection of a commercial RO membrane was tested under different conditions. In addition, the performance of an osmotic membrane crystallization setup was evaluated, considering the effect caused by the flow rates and the concentration of both the feed and the osmotic solution on the mass transfer coefficient. The crystallization process allowed the production of pure NaF crystals with octahedral morphology with a face-centered cubic crystal system.

Background: The energy crisis is a growing problem around the world, requiring the creation of alternative energy sources that can generate less carbon dioxide and benefit the ecosystem. Reutilization of wastewater is becoming the emerging energy solution. Wastewater contains a large amount of organic matter that can be oxidized in microbial fuel cells (MFCs) to produce electricity. MFCs use biodegradable materials to create energy in the presence of microorganisms. Methods: Purposive sampling technique was employed to collect samples from critical polluting sources. The samples were certainly maintained in a refrigerator at 4°C. Several mixes for sample were prepared and tested analytically- for physio-chemical and bacteriological characterizations of each substrate status at pre- and post-treatment stages. Electricity generating capacity of MFCs that employing different substrates was investigated experimentally using batch reactors. The cross-sectional methodology was employed to study possible power generation. Results: The maximum voltage output of 118.93, 144.84, and 89.76 mV were produced keeping the resistance unlimited for MFC1 (urine substrate), MFC2 (blackwater substrate), and MFC3 (graywater substrate), respectively. MFC that utilized graywater as a substrate brought the tiniest quantity of electricity; however, it stood the most stable. The highest COD reduction (65.83%) in the process was reported in urine substrate and the highest BOD5 removal (69.18%) was reported in black water substrate. Conclusion: The experimental results provided a promising indication of MFCs viability, providing hope for future power generation and alternative wastewater treatment option in developing countries.

The intensive use of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide has resulted in the presence of its residues in the environment, which leads to contamination of surface and groundwater. In this study, a fixed-bed column experiment was conducted for the removal of 2,4-D from an aqueous solution using termite mound soil (TMS). Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), atomic absorption spectrometry (AAS), and Brunauer–Emmett–Teller (BET) techniques were used to characterize the adsorbent. The effect of significant variables, such as the initial 2,4-D concentration (50 mg/L and 75 mg/L), flow rate (2.5 ml/min and 5 ml/min), solution pH (2, 4, and 6), and bed height (3, 6, and 9 cm), on the breakthrough characteristics of the adsorption system was assessed. In addition, the Thomas and Yoon–Nelson models were applied to predict the breakthrough curves and to determine the characteristic parameters of the column that are useful for process design. The findings showed that at a lower pH (2), a lower flow rate (2.5 ml/min), a lower 2,4-D concentration (50 mg/L), a higher bed depth (9 cm), and 840 min breakthrough time, a higher removal percentage (80.2%) of 2,4-D was achieved. The experimental data were in good agreement with the Thomas and Yoon–Nelson models. For the Yoon–Nelson model, the rate constant increased with an increase in the flow rate, initial ion concentration, and bed height. The time required for a 50% breakthrough decreased with an increase in the flow rate, bed height, and initial ion concentration. For the Thomas model, the rate constant increased with an increase in the flow rate but decreased with an increase in bed height and initial concentration. Overall, the study showed that termite mound soil in a fixed-bed column adsorption system presents an excellent potential for removing 2,4-D from aqueous solutions.

In the developing countries, the coffee production has no controlled disposal of coffee wastewater which has high concentrations of organic and inorganic substances and adversely affects water receiving bodies. This leads to many serious health problems in nearby areas such as ears and skin irradiation, stomach pain, nausea, respiratory problems, and freshwater zone eutrophication. In this study, the coffee processing wastewater were treated by the selected natural coagulant such as acanthus tribe, aloe vera and moringa stenopetala. The goal of this study was to optimize operating parameters on the removal of efficiency of nitrate and phosphate by using response surface methodology. The operating parameters were selected in the range of pH: 3 to 11, coagulation dose: 0.75–1.75 g, mixing rate: 40–120 rpm, and stirring time: 15–45 minutes. Coagulation or aggregation process was experimentally examined by the analysis and survey of selected natural coagulants for removal of nitrate (NO3−), and phosphate (PO43−). Design Expert (11.1.02) was used to statistically analyze the experimental data using ANOVA and the corresponding responses to evaluate the optimal state for the variables. Parameter optimization findings for pH, coagulant dosage, agitation rate, and duration were evaluated. The results of experimental analysis, when the three coagulants were mixed, the optimum conditions for the coagulant dose, pH, stirring speed, and stirring time obtained from the numerical optimization system were 0.750 g, 8.76, 80.73 rpm, and 19.23 min, respectively. The removal efficiency of mixed coagulant of Acanthus tribe, Moringa and aloe vera for NO3− and PO43− were 99.12% and 99.63%, respectively and the more effective coagulants results were obtained in the blended form.

AbstractSafety on road networks is the utmost important factor to consider for public well-being and transportation efficiency. This study introduces a new approach that combines Getis-Ord spatial statistics and crash rate analysis to identify significant road traffic accidents (RTAs) characterized by hotspots on road segments in Addis Ababa’s road network. The study’s results visually portray the crash locations, associating them with the underlying road network, which demonstrates a notable concentration of accident hotspots, between the years from 2014 to 2019 on Addis Ababa’s roads network. The RTAs spatial analysis resulted in the identification of hotspots on 33 road segments, 3 intersections, and 10 roundabouts/squares. Among the identified hotspots, the road segment recognized as Djibouti Street, extending from Bole Edna Mall to the 22 “mazoriya” roundabouts, stands out as the most significant accident hotspot. It exhibits an average of 37.5 crashes per kilometer per year, encompassing a road segment length of 1141 m. Using both methods in this study is crucial for validating findings by identifying high-crash segments and enhancing their reliability and hotspot accuracy. This unique validation method links each traffic accident’s spatial data with the road network using both crash rate and spatial statistical analysis, effectively pinpointing accident hotspots. Given the limited resources, this approach enhances awareness of accident-prone locations, enabling the prioritization of safety measures to improve road safety. It effectively addresses spatial analysis gaps related to RTAs in Ethiopia and holds practical significance by identifying and prioritizing safety measures aimed at reducing accidents within Addis Ababa’s road network.

Heavy metals pollution of both surface and groundwater sources of sub-Saharan Africa is alarmingly increased due to unplanned urban populations. Inadequate policies for water management, political commitment, and financial resources forced 65% of rural communities of sub-Saharan Africa to live in economic water stress areas. Sugarcane bagasse (SCB) shows high heavy metals (HMs) adsorption capacity (20–700 mg/g) through chemical entrapments to carbon-oxygen containing functional group and interior pore filling of porous surface. Various modifications like a physical/thermal, chemical, and composite form of bagasse show better adsorption performance for HMs removal. Kinetic and isotherm studies of HMs adsorption equilibrium data over SCB show that both Langmuir and Freundlich adsorption isotherms (cooperative adsorption) as the main adsorption mechanism. In addition, SCB shows potential bio-adsorbent properties for the selective adsorption of target HMs based on their physicochemical properties and shows good repeatability in acid environments. It is believed that information on this review will shed light on the current and future prospects of raw and modified SCB for HMs adsorption removal capacity. Sugarcane bagasse shows a remarkable selectivity for HMs adsorption removals based on their physicochemical properties and shows good potential capability for future utilizations in real wastewaters of developing countries. HIGHLIGHTS Bio-adsorbent (e.g. sugarcane bagasse) can be regenerated.; Sugarcane bagasse has high adsorptive capacity for both anion and cation heavy metals.; Cooperative adsorptive mechanism is well explained by Freundlich and Langmuir isotherms.;

The environmental industry has demonstrated an increasing interest in employing electrocoagulation (EC) process to treat industrial wastewater/effluent for recycling/drinking purposes. An iron (Fe)/aluminum (Al) plate-based batch recirculation electrocoagulation technology for wastewater treatment in the distillery industry is discussed in this work. The impact of different operational parameters, including COD, wastewater pH, current, inter-electrode spacing, combination of electrodes, recirculation flow rate, concentration of electrolytes, and treatment duration on % color, % COD reduction efficiency, and energy consumption was examined. The experimental outcomes demonstrated that, the color removal was 100 %, COD removal was 99.90 %, and energy consumption was 7.73 kWh m−3 for COD of 3600 mg L−1, current of 0.56 Amp, combination of electrodes of Fe/Fe, inter-electrode spacing of 1 cm, wastewater pH of 7, flow rate of 15 L h−1, concentration of electrolytes of 5 g L−1, and treatment time of 180 min, respectively. It was found that, a longer treatment period, higher electrolyte concentrations and current, lower COD concentrations and recirculation flow rates, Fe/Fe electrode pairings, a pH of 7, and a smaller inter-electrode spacing all contributed to increased % COD reduction efficiency. The quantity of solid sludge formed were studied with the help of operational parameters, and the results were reported. Under the optimized process conditions, the wastewater treated can be fully recovered as clean water. As a consequence of this, the results of the experiments have shown that the batch recirculation electrocoagulation process has the potential to be a more promising solution to the problem of eliminating contaminants from wastewater and industrial effluent.

Currently, millions of people are exposed to dangerous levels of chemical and biological water pollution in drinking water due to source contamination. The rising of populations and industrialization or agricultural wastewaters were causes of water contaminations. The aim of this study was to design, develop and performance evaluation of point of use drinking water purification technology using MoringaOleifera seed coupled followed by scoria coag-filtration media. Experimental laboratory based aquas solution of contaminated water was prepared for evaluations. Moringa Oleifera seed coagulation/flocculation and sedimentation tests were carried out using jar test with the batch experiment. The potential treatment of the sequential ordered unit process stages were evaluated by the determination of physicochemical parameters of the water; such as turbidity, Color, PO4−3, Fe+3 and F−concentration. The factor that affects the purification where coagulant doses, pH, and contact time. Based on this, the physicochemical parameter analysis indicated that turbidity from (150-8NTU), PO4−3 (20–5.95 mg/L), Fe+3 (7–2.93 mg/L) and F− (9–2.83 mg/L), Moringa Oleifera seed dose (10–40 mL/L) extract paste. The maximum pollutant removal efficiency was achieved at 35 mL/L of Moringa Oleifera seed extractdose, within 6.5–7.5 pH range. Then VSco filtration was conducted after jar test under small column experiment as a function of contact time (0, 2, 4 h s). The VSco removal capacity showed that the removal of turbidityfrom (8–2.54NTU), PO4−3 (5.95–1.07 mg/L), Fe+3 (2.93–0.43 mg/L) and F− (2.83–1.94 mg/L) were achieved after 4hr detention time. The percent removal of turbidity, PO4−3, Fe+3 and F− increases remarkably with increasing of their initial concentration. At an initial concentration of turbidity (150NTU), PO4−3 (20 mg/L), Fe+3 (7 mg/L) and F−(9 mg/L), the removal efficiency were 98%, 84%, 85% and 60% respectively. Therefore, we recommend Moringa Oleifera seed –Vscoas an economic, efficient and simple Point of Use drinking water treatment technology.

The present research work investigated the removal efficiency of acid-activated bentonite blended with a sugarcane bagasse ash (SCBA) adsorbent for the removal of reactive red 198 (RR198) from a synthetic dye solution. The effect of the adsorption parameters of bentonite on SCBA blending ratio, dye solution pH, adsorption contact, adsorbent dosage, and initial dye concentration was investigated, and the parameters were optimized for maximum RR198 removal from the synthetic dye solution. At an optimum condition of 1:1 bentonite to the SCBA blending ratio, a solution pH of 2, 3.7 g/L of adsorbent dosage, and 15 mg/L of initial dye concentration 150 min of adsorption time, the properties of adsorbents such as adsorbent specific surface area, crystalline phase structure, functional groups, and surface morphologies of the adsorbents were investigated. At optimum conditions, 97% RR198 removal efficiency of the adsorbent was achieved. In order to determine adsorption kinetics and isotherm models, different adsorption models were employed. It was observed that the adsorption of the RR198 dye into the acid-activated bentonite blended with the SCBA adsorbent was represented well by the Langmuir isotherm model and the adsorption kinetics order was found to be the pseudo-second order. HIGHLIGHTS Regenerable and low-cost adsorbents.; Removal of reactive dye using blended inorganic and organic adsorbents.; Principle of waste to wealth.; Improving the quality of industrial wastewater effluents.;

Increasing urbanization and industrialization are impacting on water quality globally. In the Awash River basin, Ethiopia, these drivers are impacting on water quality with further impacts created due to changes in water management releasing geogenic contaminants. The resulting water quality has potential to cause significant ecological and human health impacts. The physicochemical and heavy metals saptio-temporal variability and their associated risks to human health and ecology were assessed across twenty sampling stations in the Awash River basin. Over twenty-two physicochemical and ten heavy metals parameters were analyzed using different instruments including inductively coupled plasma mass spectrometer (ICP-MS). Elevated levels of heavy metals (As, V, Mo, Mn, and Fe) were detected in the surface water, surpassing the drinking water quality standards set by the World Health Organization (WHO). Seasonal variation was evident with peak concentration of As, Ni, Hg, and Cr were recorded in the dry season. A water quality index, hazard quotient, hazard index, heavy metal pollution index and heavy metal evaluation index were formulated to assess the potential risks to both human health and the environment. The highest values of heavy metal pollution index (HPI) above the threshold (>100) were observed in stations at Lake Beseka with HPI values ranged from 105 to 177. Similarly, the highest values of the heavy metals evaluation index (HEI) were observed in stations situated at cluster 3. The evaluation of health risk that is not related to cancer through hazard quotient demonstrated that in the case of both dermal and ingestion contact, cluster C3 > C1 > C4 > C2 and C3 > C4 > C2 > C1 were observed in children and adults, respectively. Overall, measures to reduce potential pollution risks must be taken in accordance with the standards in the river basin. Nevertheless, further research on the toxicity of heavy metals that pose risks to human health is also necessary.

Adsorption offers an efficient, cost-effective, and eco-friendly method for the treatment of dye-laden wastewater. This work presents reactive red 198 (RR198) removal by adsorption using bentonite clay (BC) blended with sugar cane bagasse ash (SCBA). The adsorbent's surface morphologies, crystalline phase structures, functional groups, and specific surface before and after adsorption were examined using SEM, XRD, FTIR, and BET respectively. Central composite design (CCD) under response surface methodology (RSM) was applied to optimize independent and dependent variable values. The optimal parameters for RR198 removal using the blended adsorbent were 107 minutes contact time, 0.934 g/L adsorbent dose, and 15 mg/L initial dye concentration, and 85.2% RR198 removal efficiency was achieved. The sorption isotherms and kinetics were evaluated using various existing models. The Freundlich isotherm model (R2 = 0.95) and the pseudo-second-order equation best described the adsorption parameters and the RR198 adsorption kinetic mechanism, respectively. Desorption and reusability experiments in batch study confirmed that BC blended with SCBA can be used multiple times for dye removal from wastewater. HIGHLIGHTS Bentonite blended with SCBA as adsorbent removed RR198 from synthetic solution successfully.; The highest RR 198 removal efficiency from water was at pH 2.; CCD under RSM was applied to determine optimal parameters of independent and dependent variables.;

Land allocation has been an important issue in land use planning research studies. Land allocation involves different multifunctional activities of maximizing environmental, economic and social benefits. Multi-criteria decision making (MCDM) method is the most popular tool to optimize land allocation problems by considering decision variables, conflicting objectives, and criteria. Hence, decision-makers face problems on how to optimize the land allocation while minimizing the conflicting trade-offs existing in the decision analysis. With this review study, we aim at identifying and extracting information on MCDM methods to solve land allocation problems from English language articles published between 2000 and 2019 and indexed by four scientific literature databases (Web of Science, Science Direct, Scopus, Google scholar). To this end, we applied a systematic literature review approach, i.e. the Preferred Reporting Items for Systematic Reviews and Meta-Analysis procedure (Moher et al., 2009), with a structured database search expression. 120 articles were selected of which, after careful screening of title, keywords and abstract, 69 were retained for detailed review. This review study report compiles comprehensive information by classifying the papers into application area, optimization objectives, criteria used, decision techniques, publication year and study region. In summary, we found that in the last two decades, the use of the MCDM method has increased, particularly in Europe and China. AHP (analytical hierarchal process) is frequently used for multi-attribute land allocation problems with reference to ecotourism and ecosystem management. LP (linear programming) and SA (simulating annealing) methods are predominantly used to optimize multi-objectives complex agricultural and forest land allocation problems respectively.

In many developing countries, such as Ethiopia, water quality and the risk of water-related diseases are serious public health issues. The present study goal was to assess the drinking water quality from source to household tap water. To characterize and analyze drinking water quality parameters, 21 water samples were collected, of which 11 water samples were collected from sources (spring, borehole, and river), 4 from service reservoirs, and 6 from tap water. The mean values of the parameters were as follows: total dissolved solids (TDS) (142.79 mg/L), temperature (22.08°C), turbidity (9.49 NTU), electrical conductivity (EC) (250.14°μS/cm), pH (7.45 mg/L), fluoride (1.15 mg/L), nitrate (NO3−) (2.91 mg/L), total hardness (TH) (57.45 mg/L), calcium (41.7 6 mg/l), magnesium (10.74 mg/L), phosphate (0.44 mg/L), sulfate (3.99 mg/L), residual chlorine (1.53 mg/L), alkalinity (196.39 mg/L), and microbiological (total coliform and coliform/CFU) which were the main physiochemical parameters analyzed for the study. The findings revealed that the majority of the water quality parameters tested were within the WHO and National Drinking Water Quality Standards (NDWQS). However, some of the parameters such as temperature, turbidity, fluoride, and residual chlorine did not meet the standards. The mean temperatures at the source, reservoir, and tap water were 22.01°C 22.5°C,and 21.83°C, respectively. Turbidity levels in source samples ranged from 10 to 45 NTU, with a mean of 24.5 NTU, exceeding the WHO’s recommendation of less than 5 NTU. The Boko Alamura well had a high fluoride content (3.9 mg/l), which was above the WHO and NDWQS permissible limits. There was no free residual chlorine in the tap water sample. The results show that the Hawassa drinking water supply did not contain total or fecal coliform in any of the samples tested. The overall WQI for the water source, reservoir, and tap water was also determined to be 89, 71, and 69.7 points, respectively. Therefore, based on the WQI result, Hawassa drinking water quality is good for the source, reservoir, and tap water.

Road accidents are a significant negative outcome of transportation systems, causing injuries, fatalities, traffic congestion, and economic losses. As cities expand and the number of vehicles on the road increases, traffic accidents (TAs) have become a significant problem. Studies have shown that urban development plays a more significant role in transportation safety than previously thought. Low-income countries have higher fatality rates than high-income countries, according to the Permanent International Association of Road Congress (PIARC) and the World Health Organization (WHO). Predicting and preventing the occurrence of accidents and congestion is necessary worldwide, especially in developing countries where fatality rates are higher. The objective of this study is to examine and make a comparative analysis in low-income and high-income countries of the existing literature on the global challenge of car accidents and use its prediction techniques to enhance road safety and reduce traffic congestion. The study evaluates various approaches such as logistic regression, decision tree, random forest, deep neural network, support vector machine, random forest, K-nearest neighbors, Naïve Bayes, empirical Bayes, geospatial analysis methods, and UIMA, NSGA-II, and MOPS algorithms. The research identifies current challenges, prevention ideas, and future directions for preventing accidents and congestion on the road network. Integrating GIS-based spatial statistical methods and temporal data and utilizing advanced optimization algorithms and machine learning methods can result in accurate prediction models that can help identify accident hotspots and reduce congestions and enhance traffic safety and mitigate their occurrence. Effectively preventing urban traffic congestion requires the integration of spatial data into precise accident prediction models. By employing spatial analysis, road safety planning can be enhanced, high-risk areas can be identified, interventions can be evaluated, and resources can be optimally allocated to facilitate effective road safety measures and decision-making, especially in settings with limited resources. Therefore, it is crucial to consider ML and spatial analysis techniques and advanced optimization algorithms to enhance traffic flow control, in road safety research and transport planning efforts.

Improvement in subgrade soil has always been an area of concern for highway and geotechnical engineers. Weak subgrade soil results in a greater thickness of the pavement layer, which increases the cost of pavement construction. It further leads to large deformations, which in turn cause continuous deterioration of the paved surface. To solve this problem, various engineering solutions and soil improvement mechanisms were previously proposed. This study was designed to investigate the stabilization of weak subgrade soil with nylon synthetic fiber (NSF) in a compromising combination. Previously, some investigations used a lower fiber content with a higher fiber length, whereas others used a lower fiber length with a higher fiber content. However, this investigation was uniquely designed to stabilize weak subgrade soil with the consideration of appropriate fiber length (10 mm and 20 mm) and content (0.5%, 1%, 1.5%, and 2.5%). The engineering properties of the soil, the effect of NSF on weak subgrade soil, various fiber content and aspect ratios, and the optimum content and critical fiber aspect ratio were investigated in a laboratory. The effect of fibers on compaction, CBR values, and CBR swell values has also been studied. Laboratory results on the modified compaction tests showed that maximum dry density (MDD) was increased with the increment of fiber content, whereas optimum moisture content (OMC) remained constant. The soaked CBR and CBR swell values of natural soil were 1.80% and 8.95%, respectively. Due to reinforcement, the percentage increase in soaked CBR value at the optimum NSF content is 265.3, 310.0, 282.8, and 342.2 for aspect ratios of 33.33, 66.67, 25, and 50, respectively, with reference to natural soil. Also, the percentage decrease in swelling is 34.7, 52.75, 43.55, and 36.9, respectively. Moreover, the CBR value increases with the increase in aspect ratio by keeping the diameter constant and decreases with the increase in aspect ratio by keeping the length constant. It was also observed that increasing the length and diameter of NSF further increased the CBR value of reinforced soil. This increment was substantial at a fiber content of 1.5% for an aspect ratio of 50 (length = 20 mm, diameter = 0.4 mm). There was also a decrease in the CBR swelling value with an increase in fiber content. Finally, this investigation concluded that the use of NSF is a solution to weak soils with regard to moisture and performance problems.

In today’s world, where the need for construction projects is increasing from time to time, especially in developing countries such as Ethiopia, sustainability issues and principles were not exercised by construction professionals during the material selection process. At the initial stage, the designer considers materials he/she is familiar with. However, their assumption may not work because the structure that is going to be developed may be different from the previous one. Thus, the designer shall consider sustainability issues during the design period. This article will guide construction stakeholders in the selection of sustainable building materials, specifically masonry materials in the Ethiopian construction industry. The research was carried out in the Addis Ababa Lideta subcity, to identify sustainable building materials for masonry work. The selection process is not depending on a single factor rather it depends on multifactors. The identification was carried out through exploring factors affecting the selection of sustainable building materials for masonry work. The weights of identified factors were determined by pairwise comparison among the factors under consideration. The research is of the empirical type which uses mathematical formula, matrix concept, and analytical hierarchy process (AHP) as a model. In this method, pairwise comparisons were made among the criteria and subcriteria so that the weights of the criteria or subcriteria/or alternative on the bases of the indicated criteria were computed. Then, prioritization was made on the bases of the weight of the criteria. Finally, an alternative with a high score shall be selected. The article identifies the major factor affecting the selection of sustainable building materials for masonry work as social benefit, performance capability, sustainability of the material to reduce environmental impact, waste minimization, resource efficiency, and life cycle cost of the material. Under each criterion, there are number of subcriteria contributed to them. On the basis of the above criteria, 4 alternatives (stone, brick, CEB, and cement block) were proposed from which compressed Earth block (CEB) was selected.

The feasibility of fluoride adsorption from aqueous solutions using naturally available bentonite clay in both modified and unmodified forms is investigated in this report. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy analysis was applied to describe the structure and nature of modified and unmodified bentonite clay. The physicochemical characteristics of the adsorbent were also investigated for moisture content, pH, apparent density, specific surface area, cation exchange capacity and its point-of-zero charge. SEM images reveal particles are dispersed homogeneously and are irregular in shape. XRD and EDX analyses reveal that the bentonite is composed of seven materials: calcite, silica, alumina, hematite, bornite and green cinnabar, and chloride which are considered as impurities. Raw bentonite clays have shown very low fluoride removal efficiency (47.19%). Modification of the clay surface with HCl and aluminum oxide, on the other hand, increased fluoride removal efficiency to 79.77% and 94.38%, respectively. At 5 mg/L initial fluoride concentration, 10 cm bed depth packed dose of adsorbent, and 180 min breakthrough time, a 2.88 mg/g of fluoride removal capacity was observed. As a result, aluminum oxide modified bentonite clay was chosen for further investigation and the results are not presented here. HIGHLIGHTS Clay minerals adsorption experimentation for low fluoride concentrations (5, 10, and 12 mg/L) was successful.; Most of the experimentation done so far are in batches using clay-based minerals and leads to shorter reaction times and thus are not at equilibrium.; Column experimentation using clay minerals was difficult, but this study used the clay as a filter media through surface modification of the adsorbent.;

Abstract Wastewater generated from different sources affects the health of living organisms and the natural environment due to the availability of different pollutants. Electrocoagulation (EC) is a good technology implemented for wastewater treatment before discharging to an environment as effluents. The electrocoagulation process is an effective method to the remove the color, chemical oxygen demand (COD), turbidity, and consumption of less energy from wastewater by considering different operating parameters. In this study, the major operating parameters for the electrocoagulation process such as pH (3–7.50), electric current (0.03–0.09 A), electrolytic concentration (1–3 g/L), the distance between electrodes (1–2 cm), electrolysis time (20–60 min) and combination of electrodes (Fe–Fe and Al–Al) were studied. The maximum removal of color–94.40%, COD–97.02%, and turbidity–90.91% with required energy consumption –36kWhr/m3 was obtained at the electric current–0.09 A, electrolyte concentration–3 g/L, pH–7, electrode combination–Fe–Fe, and distance between electrodes–3 cm, respectively. The studied parameters were affected the removal % color, % COD, % turbidity, and also the consumption of energy depending on the desired setup of fixed values of the parameter. Consumption of energy and electrode dissolution is related to the cost of operating in electrocoagulation in addition to the cost of labor and the small amount of sludge produced for disposal.

Abstract Background Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) is among the economically most important freshwater fish species in East Africa, and a major source of protein for local consumption. Human induced translocations of non-native stocks for aquaculture and fisheries have been found as a potential threat to the genetic diversity and integrity of local populations. In the present study, we investigate the genetic structure of O. niloticus from 16 waterbodies across Ethiopia using 37 microsatellite loci with SSR-GBAS techniques. Results The samples are structured into three main clusters shaped either by biogeographic factors or stocking activities. High F ST values (Global F ST = 0.438) between populations indicate a high level of genetic differentiation and may suggest long term isolation even within the same drainage systems. Natural populations of the Omo-Turkana system and the lakes in the Southern Main Ethiopian Rift showed the highest genetic variability while low variability was found in stocked populations of lakes Hora, Hashenge and Hayq. Conclusions The results presented herein, may provide an essential basis for the management and conservation of the unique genetic resources in northern East Africa, and advance our understanding of biodiversity, phylogeny, evolution and development towards phylogenetically more accurate taxonomic classifications.

In the present study, a hybrid cotton fabric with an enhanced ultraviolet (UV) shielding property was developed by coating with functionally activated nanocarbon (FACN) which was grafted by polyaniline (PANI) using in situ polymerization. In light of this, Teff hay biomass was used to establish the activated nanocarbon (ANC), that was subsequently given a surface functionalization using a silane coupling agent. Using the response surface (RSM) statistical analysis, the study was optimized for the weight percent of ANC and PANI with respect to the cotton fabric that was found to offer remarkable UV protection, with an ultraviolet protection factor (UPF) of 64.563, roughly 17 times more than that of primitive cotton (UPF = 3.7). The different characterization techniques, such as UV absorption, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thermal behavior studies were investigated. In addition, the basic textile properties on optimized hybrid material were found to be appreciably increased. The results suggested that activated FACN made from Teff hay could be an effective alternative organic source material for developing UV protective hybrid cotton fabrics.

Sebeta town is one of the rapidly growing towns in Ethiopia. Its closeness to Addis Ababa city has attracted industrial, urban development, and population growth. This development has created problems with drinking water shortages in the community. This study aimed at determining the household's willingness to pay (WTP) amount toward improving water supply services and analyzing the influencing factors of WTP. A contingent valuation (CV) technique was applied in quantifying the households' WTP and the influencing factors toward the program. The field observations, key informant interviews, and household questionnaire interviews from 250 respondents out of the targeted 280 were employed in collecting field data. Results from CV revealed that 66% of the households were WTP toward improving the water supply services beyond their current monthly water bills. Households were WTP about 20 Ethiopian Birr (ETB) above the average current water bill of 161 ETB. The binary logistic model results statistically demonstrated that independent variables of gender, age, marital status, education level, years in Sebeta, and average monthly income were significantly influencing the household's WTP at p = 0.01 and 0.05. This study provides vital hints for further research and baseline information for local administration and communities about the water supply in the area and holistic appropriation of water tariffs in line with government policy. HIGHLIGHTS 250 respondents out of the targeted 280 were used in the study.; 66% of the households were WTP toward the program.; Households were willing to add 20.046 ETB above their current monthly water bill.; Gender, age, marital status, educational level, and monthly income were the influencing factors toward households’ WTP.;

Water pollution by organic contaminants is one of the most severe issues confronting the world today as a result of the rapid increase of industrialization, urbanization, human population growth, and advances in agricultural technologies. Several attempts have been made to address global water pollution issues by utilizing conventional wastewater treatment technologies. However, conventional wastewater treatment methods have several limitations such as low efficiency, high operation costs, generation of secondary waste, require additional chemicals as oxidants and extra energy. Therefore, Heterogeneous photocatalysis has gained a lot of attention in the degradation of persistent organic pollutants because it combines high efficiency, environmental friendliness, cheap cost, and safety. Subsequently, the designing of novel nanocomposite photocatalysts with strong visible light-harvesting ability, efficient charge separation and transportation, and superb stability is imminently desired for wastewater treatment. Recently, the notion of combining g-C 3 N 4 with TiO 2 to design high photocatalytic performance heterojunction photoactive nanocomposites for organic pollutant degradation has received a lot of attention. Meanwhile, the construction of g-C 3 N 4 /TiO 2 -based heterojunction nanocomposites may enhance the ability of harvesting visible light, boost charge separation and transfer efficiency, and robust photocatalytic activity. Firstly, this review concisely explained the main sources of water pollution, as well as potential treatment approaches and the fundamental mechanism of heterogeneous photocatalysis. Subsequently, the details of properties, synthesis techniques, photoactivity modification strategies, and photocatalytic applications of g-C 3 N 4 , TiO 2, and g-C 3 N 4 /TiO 2 heterojunction photocatalysts are presented. Following that, the recent advances aimed at improving the photocatalytic performance of various types of visible-light-driven g-C 3 N 4 /TiO 2 heterojunction photocatalysts for organic pollutant degradation in wastewater are presented in detail. Finally, some concluding remarks and perspectives on the challenges and opportunities for constructing different types of g-C 3 N 4 /TiO 2 -based heterostructured photocatalysts are presented.

Electrocoagulation (EC) is a process used by supply of electric current with sacrificial electrodes for the removal of pollutant from wastewater. The study was experimentally investigated taking into account various factors such as pH (3–7.5), current (0.03–0.09 A), distance between the electrodes (1–2 cm), electrolytic concentration (1–3 g/L), and electrolysis time (20–60 min) which is impact on the % removal efficiency of color, chemical oxygen demand (COD), turbidity and determination of energy consumption used for aluminum (Al) electrode used. The surface response design process based on the central composite design (CCD) has been used to optimize different operational parameters for treatment of hospital wastewater using EC process. The % color, COD and turbidity removal, and energy consumption under different conditions were predicted with the aid of a quadratic model, as were the significance and their interaction with independent variables assessed by analysis of variance (ANOVA). The optimal conditions were obtained through mathematical and statistical methods to reach maximum % color, COD, and turbidity removal with minimum energy consumption. The results showed that the maximum removal of color (92.30%), COD (95.28%), and turbidity (83.33%) were achieved at pH–7.5, current–0.09A, electrolytic concentration–3g/L, distance between electrodes–2 cm and reaction time 60 min. This means that, the process of EC can remove pollutants from various types of wastewaters and industrial effluent under the various operating parameters.

Climate extreme like drought significantly affect the quality of the environment and threaten food availability in developing countries like Ethiopia. In this study, satellite-based agricultural drought assessments were conducted in the 0main crop growing season (June to September) using Landsat 8 images of five periods (2015 to 2019) in the Rift Valley Region of Ethiopia. To assess the agricultural drought we used Normalized Difference Vegetation Index (NDVI), Land Surface Temperature (LST), Vegetation Condition Index (VCI), Temperature Condition Index (TCI), and Vegetation Health Index (VHI). The results indicate that the main crop growing season was experienced by drought and wet which vary from extremely dry to extremely wet. The value of VHI, the cumulative effects of TCI and VCI, revealed that 2016 was the most drought-prone while 2019 was the wettest year. Results of NDVI and LST showed a negative correlation. Results showed that drought was more severe in the lowland areas than highland areas in the study area. Accordingly, high drought was observed in the northern and central parts of the study area. It is obvious that the lowland areas face a precipitation deficit because of high temperature and evapotranspiration. This study suggests that satellite-based indices were crucial to provide early warning systems for the farming communities and to suggest adaptation options that minimize the potential impacts of agricultural droughts on people's livelihoods and wellbeing. Moreover, further research should be conducted by incorporating other social and biophysical factors to enhance the understanding of agricultural drought and its effect on the economy of the agricultural communities.

Nowadays, increased human activity, industrialization, and urbanization result in the production of enormous quantities of wastewater. Generally, physicochemical and biological methods are employed to treat industrial effluent and wastewater and have demonstrated high efficacy in removing pollutants. However, some industrial effluent and wastewater contain contaminants that are extremely difficult to remove using standard physicochemical and biological processes. Previously, electrochemical and hybrid advanced oxidation processes (AOP) were considered a viable and promising alternative for achieving an adequate effluent treatment strategy in such instances. These processes rely on the production of hydroxyl radicals, which are highly reactive oxidants that efficiently break down contaminants found in wastewater and industrial effluent. This review focuses on the removal of contaminants from industrial effluents and wastewater through the integration of electrochemical and advanced oxidation techniques. These processes include electrooxidation, electrocoagulation/electroflocculation, electroflotation, photo-Fenton, ozone-photo-Fenton, sono-photo-Fenton, photo-electro-Fenton, ozone/electrocoagulation, sono-electrocoagulation, and peroxi/photo/electrocoagulation. The data acquired from over 150 published articles, most of which were laboratory experiments, demonstrated that the hybrid process is more effective in removing contaminants from industrial effluent and wastewater than standalone processes.

Ozonation is one of the most effective and efficient advanced oxidation processes (AOPs) and has shown great potential in the treatment of industrial effluent and wastewater. In the present work, the ozone-Fenton process for % COD and color removal together with electrical energy per order (EE/O) determination for distillery industrial wastewater (DIW) was established. The process was developed by combining the ozone (O3) with the Fenton (Fe2+/H2O2) process. The ozone-Fenton (O3/Fe2+/H2O2) was compared with other treatment processes such as O3, Fe2+, H2O2, O3/Fe2+, O3/H2O2, and Fe2+/H2O2 for EE/O together with % COD and color removal efficiency for DIW. The removal of color at 100% and chemical oxygen demand (COD) of 96.875% were achieved with a minimum of EE/O of 0.5315 kWh/m3 using the O3/Fe2+/H2O2 process by operating at optimum conditions. The % COD and color values obtained using O3/Fe2+/H2O2 were significantly higher than those obtained using O3, Fe2+, H2O2, O3/Fe2+, O3/H2O2, and Fe2+/H2O2 processes. The % color, % COD removal, and its associated EE/O were evaluated by varying Fe2+, H2O2, O3 inlet and COD concentration, and initial wastewater pH using the O3/Fe2+/H2O2 process. The synergy effect of the O3 and Fe2+/H2O2 processes was evaluated and reported. Our experimental findings suggest that combining O3 with the Fe2+/H2O2 process could effectively treat industrial effluent and wastewater.

Recently, polymeric graphitic carbon nitride (g-C3N4) has been explored as a potential catalytic material for the removal of organic pollutants in wastewater. In this work, graphitic carbon nitride (g-C3N4) photocatalysts were synthesized using mixtures of low-cost, environment-friendly urea and thiourea as precursors by varying calcination temperatures ranging from 500 to 650 °C for 3 h in an air medium. Different analytical methods were used to characterize prepared g-C3N4 samples. The effects of different calcination temperatures on the structural, morphological, optical, and physiochemical properties of g-C3N4 photocatalysts were investigated. The results showed that rhodamine B (RhB) dye removal efficiency of g-C3N4 prepared at a calcination temperature of 600 °C exhibited 94.83% within 180 min visible LED light irradiation. Photocatalytic activity of g-C3N4 was enhanced by calcination at higher temperatures, possibly by increasing crystallinity that ameliorated the separation of photoinduced charge carriers. Thus, controlling the type of precursors and calcination temperatures has a great impact on the photocatalytic performance of g-C3N4 towards the photodegradation of RhB dye. This investigation provides useful information about the synthesis of novel polymeric g-C3N4 photocatalysts using a mixture of two different environmentally benign precursors at high calcination temperatures for the photodegradation of organic pollutants.

Abstract Background The need for enhancing the productivity of fisheries in Africa triggered the introduction of non-native fish, causing dramatic changes to local species. In East Africa, the extensive translocation of Nile tilapia (Oreochromis niloticus) is one of the major factors in this respect. Using 40 microsatellite loci with SSR-GBS techniques, we amplified a total of 664 individuals to investigate the genetic structure of O. niloticus from East Africa in comparison to Ethiopian and Burkina Faso populations. Results All three African regions were characterized by independent gene-pools, however, the Ethiopian population from Lake Tana was genetically more divergent (Fst = 2.1) than expected suggesting that it might be a different sub-species. In East Africa, the genetic structure was congruent with both geographical location and anthropogenic activities (Isolation By Distance for East Africa, R2 = 0.67 and Uganda, R2 = 0.24). O. niloticus from Lake Turkana (Kenya) was isolated, while in Uganda, despite populations being rather similar to each other, two main natural catchments were able to be defined. We show that these two groups contributed to the gene-pool of different non-native populations. Moreover, admixture and possible hybridization with other tilapiine species may have contributed to the genetic divergence found in some populations such as Lake Victoria. We detected other factors that might be affecting Nile tilapia genetic variation. For example, most of the populations have gone through a reduction in genetic diversity, which can be a consequence of bottleneck (G-W,

Abstract Freeze desalination, i.e., desalination of water by freezing it, may be an option to treat polluted water at individual household level. Taking into account the widespread fluoride contamination of Ethiopian water resources and with the reason that most households in semi-urban and urban areas do have easier accessibility of refrigerators, this study aimed to investigate the defluoridation capacity of freeze desalination and its energy consumption for different water sources. For this purpose, synthetic solutions that emulate the major ion compositions of natural waters (hereafter called simulated water), tap water, and double-distilled water to which variable concentrations of fluoride ions were added were evaluated using home-use insulated refrigerator (BEKO, RRN 2650). The effects of conditions such as initial fluoride concentration, multi-ion existence, fraction of ice frozen, volume of the container, and freezing duration were evaluated in relation to the produced ice quality. It was found that nearly 48% and 62% removal of fluoride were achieved from tap water spiked with 10 mg/L F− and 10 mg/L F− aqueous solutions, respectively, with a total water recovery of 85 to 90%. The energy consumption predicted to produce the ice from tap water spiked with 10 mg/L F− and double-distilled water alone was found to be 93.9 and 91.8 kJ/L, respectively. The results showed that freeze desalination can be a potential technique for fluoride removal from water to be used as drinking water at household level in semi-urban and urban areas as well as in colder regions.

The objective of this study was to evaluate the treatment efficiency of a coupled stillage anaerobic digestion, which was performed in scoria-packed continuous reactors and following aerobic degradation. The optimum organic loading rate was determined for the continuous anaerobic digestion of a molasses ethanol distillery stillage with and without wet air feed pretreatment. The pretreatment of the molasses ethanol distillery stillage brought a significantly higher chemical oxygen demand removal in anaerobic digestion with an increased loading rate of 2000 mg/L d when compared with the raw stillage. The results also showed a complete removal of the biological oxygen demand following the coupling of anaerobic digestion with aerobic degradation. During the later stillage aerobic treatment, 68% of the chemical oxygen demand was removed within 8 hours of retention time. Despite the color, the removal of organics in stillage due to integrating wet air pretreatment, continuous anaerobic digestion, and aerobic degradation was successful. The pretreatment and hybrid technique also appears as a promising technique toward the sustainable management of stillage, thereby meeting discharge limit set for the ethanol industry by regulators.

Visual characteristics are among the most important features for characterizing the phenotype of biological organisms. Color and geometric properties define population phenotype and allow assessing diversity and adaptation to environmental conditions. To analyze geometric properties classical morphometrics relies on biologically relevant landmarks which are manually assigned to digital images. Assigning landmarks is tedious and error prone. Predefined landmarks may in addition miss out on information which is not obvious to the human eye. The machine learning (ML) community has recently proposed new data analysis methods which by uncovering subtle features in images obtain excellent predictive accuracy. Scientific credibility demands however that results are interpretable and hence to mitigate the black-box nature of ML methods. To overcome the black-box nature of ML we apply complementary methods and investigate internal representations with saliency maps to reliably identify location specific characteristics in images of Nile tilapia populations. Analyzing fish images which were sampled from six Ethiopian lakes reveals that deep learning improves on a conventional morphometric analysis in predictive performance. A critical assessment of established saliency maps with a novel significance test reveals however that the improvement is aided by artifacts which have no biological interpretation. More interpretable results are obtained by a Bayesian approach which allows us to identify genuine Nile tilapia body features which differ in dependence of the animals habitat. We find that automatically inferred Nile tilapia body features corroborate and expand the results of a landmark based analysis that the anterior dorsum, the fish belly, the posterior dorsal region and the caudal fin show signs of adaptation to the fish habitat. We may thus conclude that Nile tilapia show habitat specific morphotypes and that a ML analysis allows inferring novel biological knowledge in a reproducible manner.

Dyes and other chemicals laden wastewater is a main environmental concern for increasing the textile industries in many parts of the world. Textile industries consume different kinds of manmade dyes or other chemicals and release huge extents of highly polluted water into the environment. This excessive dye laden wastewater has great impacts on photosynthetic activity in aquatic plants and animals, for example, fish. It may also affect human health due to the presence of components like heavy metals and chlorine in manmade dyes. Thus, wastewater effluent from textile industries must be treated before discharge into the water body. Treatment technologies observed in this review paper include biological treatment methods (fungi, algae, bacteria, and microbial fuel cells), chemical treatment methods (photocatalytic oxidation, ozone, and Fenton’s process), and physicochemical treatment methods (adsorption, ion exchange, coagulation, and filtration). This review also includes the hybrid treatment methods and their cost per m3 of treated wastewater analysis. There are alternative wastewater treatments systems at different steps of effluent generated from the textile operational unit recommend in this review work.

This study investigates the spatial distribution and speciation of chromium in water, soil, and edible plants in tannery-contaminated areas at Modjo city, Ethiopia. Modjo city is one of the industrial zones in the country, which is dominated by tanneries due to the ease of effluent discharge and water use from the nearby Modjo River crossing the city. The river, which received chromium-containing effluent from the tanneries, is also used for urban gardening of edible plants besides other domestic purposes. 12 water and 12 soil samples from contaminated areas and 6 samples from different edible plants grown nearby tanneries were collected following the standard procedure to predict the level of chromium contamination in the environment and its health risk. The total chromium in Modjo River was 20.6 mg L−1 in the upstream region which later was significantly reduced (r = –0.93, p0.05) to the downstream sampling points. The lowest Cr (III) and Cr (VI) concentrations in the soil were 2.78 ± 0.37 and 4.57 ± 1.01 mg kg−1, respectively, which are higher (p beetroot > lettuce > cabbage > tomato > green pepper. The chromium in the plants from the contaminated area was significantly higher (p

The effect of a mild, wet air pretreatment and the subsequent anaerobic digestion (AD) was examined on the recovery of a complex and toxic molasses ethanol distillery stillage. The biogas yield and organics removal due to pretreatment were compared with the raw stillage AD. The application of a scoria support in this industrial residue AD process stability was also assessed. Consequently, a statistically significant cumulative specific methane recovery difference (p-value = 0.000) with an almost complete biological oxygen demand (BOD) removal and a significant chemical oxygen demand (COD) reduction, which were 100% and 92% respectively were achieved. Additionally, the biogas recovery rate was hastened due to pretreatment. The application of scoria, whose property has been instrumentally inspected, has helped stabilize the pH in the AD systems. In a comparative approach, this study suggests the energy benefit and an ecofriendly discharge of stillage by the ethanol industry towards sustainability.

Many people worldwide are exposed to extreme levels of fluoride in drinking water. It is, therefore, critical to develop inexpensive, locally available, and environmentally friendly adsorbents for fluoride-laden water defluoridation. In the current study, virgin scoria (volcanic rock) from Ethiopia, was modified with zirconium oxide and used as an adsorbent in a fixed-bed column aiming at the removal of fluoride from water. The adsorption capability of zirconium oxide-coated scoria (ZrOCSc) was compared with unmodified virgin scoria (VSco). XRD, FTIR, XRF, SEM, ICP-OES, and the pHPZC tests were evaluated to explore the adsorption mechanisms. Thermal analysis of VSco and ZrOCSc revealed lower total weight losses of 2.3 and 3.2 percent, respectively, owing to the removal of water molecules and OH species linked to metal oxides contained in the material. The effect of test conditions such as the pH of the solution and the influent flow rate on the adsorption capacity of the adsorbent was carefully studied. ZrOCSc exhibited the maximum removal capacity of 58 mg/kg, which was 4.46 times higher than the observations for VSco (13 mg/kg) at pH 2, and an initial flow rate of 1.25 mL/min. Breakthrough time increased with decreasing initial pH and flow rate. The adsorption experimental data under various test conditions were examined by the Thomas and Adams–Bohart models. Both models were found very effective in describing the experimental data with a correlation coefficient (R2) of ≥0.976 (ZrOCSc) and ≥0.967 (VSco). Generally, coating VSco with zirconium oxide improved the adsorption performance of VSco; hence, a ZrOCSc-packed fixed bed could be employed for the decontamination of high levels of fluoride from groundwater. However, further examination of the adsorbent using natural groundwater is advisable to produce a definitive conclusion.

Log D the logarithm (log10) of the distribution coefficient (D), is one of the important parameters used in Lipinski's rule to assess the druggability of a molecule in pharmaceutical formulations. The distribution of a molecule between a hydrophobic organic phase and an aqueous buffer phase is influenced by the pH of the buffer system. In this work, we used both the conventional algebraic method and the generalized ‘dynamic’ approach to model the distribution coefficient of amphoteric, diamino-monoprotic molecule and monoprotic acid in the presence of salt or co-solvent. We have shown the equivalence of these methods by analysing the recently reported experimental data of amphoteric molecules such as nalidixic acid, mebendazole, benazepril and telmisartan. Keywords: Dynamic approach, Log D analysis, Monoprotic, Diprotic, Mono alkaline, Amphoteric, Salt effect, Solvent effect, Diamino-monoprotic molecules

Abstract Background Diarrheal disease attributable to water and sanitation can be prevented using point-of-use water treatment. In Ethiopia, a small number of households treat water at point-of-use with appropriate methods. However, evidence on factors associated with household use of these treatment methods is scarce. Therefore, this study is intended to explore the household use of appropriate point-of-use water treatment and associated factors in Ethiopia. Methods The data of 2005, 2011, and 2016 Ethiopian demographic and health surveys were used for analysis. Households reportedly treating water with bleach, boiling, filtration, and solar disinfection in each survey are considered as treating with appropriate treatment methods. Household water treatment with these treatment methods and factors associated was assessed using bivariate and multivariable regression. In addition, a region level difference in the treatment use was assessed by using multilevel modeling. Results The number of households that reported treating water with appropriate water treatment methods was 3.0%, 8.2%, and 6.5% respectively in 2005, 2011, and 2016. Household heads with higher education had 5.99 (95% CI = 3.48, 10.33), 3.61 (95% CI = 2.56, 5.07), and 3.43 (95% CI = 2.19, 6.37) times higher odds of using the treatment methods respectively in 2005, 2011, and 2016 compared to household heads who had no education. There was a significantly high number of households that used appropriate water treatment methods in 2011 (AOR = 2.78, 95% CI = 2.16, 3.57) and 2016 (AOR = 2.18, 95% CI = 1.64, 3.89) compared to 2005 data. In pooled data analysis, the reported use of the treatment methods is associated with household head education, residency, drinking water sources, and owning radio and television. From a multilevel modeling, within-region variation is higher than between-region variations in the use of treatment methods in each survey. Conclusions Below 10% of households reportedly treating water at point-of-use in each survey attributable to different factors. Designing intervention strategies for wide-scale use of treatment methods at the country level is fundamental.

In the present study, polyaniline was coated on the surface of sisal fibers through in situ oxidative polymerization which was further characterized using FT‐IR, UV‐Vis, XRD, SEM and EDX instruments. The composite was tested to remove hexavalent chromium Cr(VI) from simulated wastewater on batch experimentas a function of contact time, solution pH, particle size, adsorbent dose and adsorbate dose. Peaks in the range of 1480‐1580 cm‐1 from FT‐IR spectra confirmed polyaniline is rich in amino polyfunctionalities. Another peak at 1160 cm‐1 proved introduction of polyaniline in the doped state. An EDX spectrum exhibits a characteristic peak of C, N, O and Cl atoms that verify deposition of polyaniline on the surface of sisal fibers. It was observed that adsorption of Cr(VI) is highly susceptible to pH change with the adsorption removal of 93.1% achieved at pH 4. Studies on adsorption reaction revealed adsorption process followed pseudo second orderkinetics confirming chemisorption as a rate determining step. The isotherm data were suitably fitted tothe Langmuir model with maximum adsorption capacity (qm) of 17.86 mg/g when all adsorption variables were optimized.

Abstract Treatment of landfill leachate wastewater by electrocoagulation process using an aluminium electrode was investigated in a batch electrochemical cell reactor. Response surface methodology based on central composite design was used to optimize the operating parameters for the removal of % color and % total organic carbon (TOC) together with power consumption from landfill leachate. Effects of three important independent parameters such as current density (X 1), inter-electrode distance (X 2) and solution pH (X 3) of the landfill leachate sample on the % color and % TOC removal with power consumption were investigated. A quadratic model was used to predict the % color and % TOC removal with power consumption in different experimental conditions. The significance of each independent variable was calculated by analysis of variance. In order to achieve the maximum % color and % TOC removal with minimum of power consumption, the optimum conditions were about current density (X 1)—5.25 A/dm2, inter-electrode distance (X 2)—1 cm and initial solution of effluent pH (X 3)—7.83, with the yield of color removal of 74.57%, and TOC removal of 51.75% with the power consumption of 14.80 kWh/m3. Electrocoagulation process could be applied to remove pollutants from industrial effluents and wastewater.