Removal of Physicochemical and Microbial Impurities of Water Using Modified Homemade Filter

Background: There are many different methods, which are used to purify water. Some are conventional and expensive, while others are traditional and small scale, still having interesting results in killing pathogenic organisms and reducing the concentration of some chemicals and other impurities, especially for rural communities of developing countries who are suffering from water borne diseases. But because conventional water treatment methods are not affordable in rural communities of developing countries, other small-scale methods are needed. An experimental study was conducted to test the effect of modified homemade filter in reduction of turbidity, fecal coliform, fluoride and its effect on pH and temperature. Method And Materials: Representative water samples were taken from’ kochi’ stream and laboratory analysis was done both for the raw water samples and the filtrates in school of environmental health laboratory, Jimma University. Filter tanks fitted with half-inch pipe were constructed and filled with stone (10 cm), gravel (9 cm), sand (40 cm) and crushed brick (10 cm) for fluoride test and local charcoal (10 cm), instead of the crushed brick for physical and biological test. Filter tanks without crushed brick, and without local charcoal were used as control. For the determination of fecal coliform, pH and temperature, turbidity and fluoride, MPN technique, pH meter, turbidimeter and Alizarin spectrophotometry method were used, respectively. Results: With a flow rate adjusted initially to 0.35 L/min the test resulted an average concentration of fluoride 1.42 mg/l (71.6%) from 5mg/l after filtered in a Modified Homemade Filter (MHMF1) with crushed brick. After a month operation the MHMF2 (with local charcoal) reduced the faecal coliform to 1 /100ml (99.95%) and turbidity to 0.13 FTU (99.83%), which was improved as the time of filter run increased and the flow rate decreased. CONCLUSION: The study showed that filtration of raw, fluoridated water with the study media could remove physical, chemical and biological impurities up to significant values for developing countries. The filter unit is very light in weight for easy transportation and costs 210 Ethiopian Birras of March 2004. Communities who have no access for treated water supplies can have this method as alternative, appropriate and cost effective technology with careful handling and timely cleaning.Ethiop J Helath Sci. Vol. 16, No.2 July 200

Freeze desalination as point-of-use water defluoridation technique

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 10mg/L F- and 10mg/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 10mg/L F- and double-distilled water alone was found to be 93.9 and 91.8kJ/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

Mobile trace elements in sediments from lakes Hawassa, Koka, and Ziway in the Ethiopian Rift Valley

acceptedVersio

Solar disinfection: an approach for low-cost household water treatment technology in Southwestern Ethiopia

Disinfection of contaminated water using solar radiation (SODIS) is known to inactivate bacteria. Its inactivation efficiency depends on local conditions where the disinfection is made. This study was aiming to test the efficiency of solar disinfection using different water parameters as low-cost household water treatment technology. Inactivation of microbes was tested using fecal coliform as test organism. The SODIS experiment was carried out at turbidity 2NTU, pH 7, and various water temperature (38.1°C, 41.8°C, 45.6°Cand 51.1°C) and solar intensities, using clear and black plastic bottles filled to different depths. The results show that the rate of microbial inactivation in relation to depth of water, turbidity, container type, intensity of light and color of container was statistically significant (p < 0.05). However, bottle placement, exposure and water pH were unrelated to microbial inactivation. Bacterial re-growth was not observed after solar disinfection. By adjusting the parameters, complete and irreversible fecal coliform inactivation was achieved within an exposure time of less than four hours in the areas where the solar irradiance is about 3.99 kW/m(2) and above. Our results indicate that application of SODIS could play a significant role in the provision of safe water in rural communities of developing countries where there is ample sunshine, specifically in sub-Saharan African countries

Session 3 - What are concepts or conditions of success for a networked VET learning and teaching (oriented on competence, working practice, flexible, etc.) and especially for a networked Further Education system in VET?

Session 3 Concepts or conditions of success for networked VET learning and teaching, especially for Further Education. Participants presented their concepts and conditions of success for a competence-based and networked VET Education and Further Education. Following the theoretical approaches of sessions 1 and 2, session 3 presents ideas and models for Further Education concepts that were tested in practice. They come from nine African universities and one German university. The authors provide supportive and obstructive factors for competence-oriented Further Education in VET

Spatiotemporal distribution and bionomics of Anopheles stephensi in different eco-epidemiological settings in Ethiopia

Background: Malaria is a major public health concern in Ethiopia, and its incidence could worsen with the spread of the invasive mosquito species Anopheles stephensi in the country. This study aimed to provide updates on the distribution of An. stephensi and likely household exposure in Ethiopia. Methods: Entomological surveillance was performed in 26 urban settings in Ethiopia from 2021 to 2023. A kilometer-by-kilometer quadrant was established per town, and approximately 20 structures per quadrant were surveyed every 3 months. Additional extensive sampling was conducted in 50 randomly selected structures in four urban centers in 2022 and 2023 to assess households’ exposure to An. stephensi. Prokopack aspirators and CDC light traps were used to collect adult mosquitoes, and standard dippers were used to collect immature stages. The collected mosquitoes were identified to species level by morphological keys and molecular methods. PCR assays were used to assess Plasmodium infection and mosquito blood meal source. Results: Catches of adult An. stephensi were generally low (mean: 0.15 per trap), with eight positive sites among the 26 surveyed. This mosquito species was reported for the first time in Assosa, western Ethiopia. Anopheles stephensi was the predominant species in four of the eight positive sites, accounting for 75–100% relative abundance of the adult Anopheles catches. Household-level exposure, defined as the percentage of households with a peridomestic presence of An. stephensi, ranged from 18% in Metehara to 30% in Danan. Anopheles arabiensis was the predominant species in 20 of the 26 sites, accounting for 42.9–100% of the Anopheles catches. Bovine blood index, ovine blood index and human blood index values were 69.2%, 32.3% and 24.6%, respectively, for An. stephensi, and 65.4%, 46.7% and 35.8%, respectively, for An. arabiensis. None of the 197 An. stephensi mosquitoes assayed tested positive for Plasmodium sporozoite, while of the 1434 An. arabiensis mosquitoes assayed, 62 were positive for Plasmodium (10 for P. falciparum and 52 for P. vivax). Conclusions: This study shows that the geographical range of An. stephensi has expanded to western Ethiopia. Strongly zoophagic behavior coupled with low adult catches might explain the absence of Plasmodium infection. The level of household exposure to An. stephensi in this study varied across positive sites. Further research is needed to better understand the bionomics and contribution of An. stephensi to malaria transmission. Graphical Abstract

Erratum: Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017

Interpretation: By quantifying levels and trends in exposures to risk factors and the resulting disease burden, this assessment offers insight into where past policy and programme efforts might have been successful and highlights current priorities for public health action. Decreases in behavioural, environmental, and occupational risks have largely offset the effects of population growth and ageing, in relation to trends in absolute burden. Conversely, the combination of increasing metabolic risks and population ageing will probably continue to drive the increasing trends in non-communicable diseases at the global level, which presents both a public health challenge and opportunity. We see considerable spatiotemporal heterogeneity in levels of risk exposure and risk-attributable burden. Although levels of development underlie some of this heterogeneity, O/E ratios show risks for which countries are overperforming or underperforming relative to their level of development. As such, these ratios provide a benchmarking tool to help to focus local decision making. Our findings reinforce the importance of both risk exposure monitoring and epidemiological research to assess causal connections between risks and health outcomes, and they highlight the usefulness of the GBD study in synthesising data to draw comprehensive and robust conclusions that help to inform good policy and strategic health planning

Treatment of Polluted Water Using Natural Rock Material at the Household Level

No abstract - Available on PD

Adsorptive removal of Cr (VI) from wastewater using magnetite–diatomite nanocomposite

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.