Browsing by Author "Feleke Adey"

Now showing 1 - 6 of 6
  • No Thumbnail Available
    Item
    A Comparative Study of Four Indigenous Cattle Breeds for Tick Resistance and Tick- Borne Diseases in Ghibe Valley
    (Addis Ababa University, 2003-06) Feleke Adey; Petros Beyene (PhD)
    The purpose of the study was to obtain information on the resistance levels of four indigenousbreeds of cattle (Abigar, Gurage, Horro and Sheko) to natural infestation with ticks in theGhibe Valley. Monthly collection of ticks from randomly selected cohort of 15 heifers ofeach breed, in the period January through October 2002, showed the most common tickspecies to be: Amblyomma variegatum (39.5%), Boophilus decoloratus (39.1%), A. cohaerens(10.5%) and Rhipicephalus evertsi evertsi (6.7%). Species of least abundance include, R.praetextatus, Haemaphysalis aciculifer, Hyalomma marginatum rufipes, R. bergeoni, R.lunulatus, R. muhsame and R. pravus, altogether comprising 4.2% of the overall tick species.The monthly abundance of adult and immature ticks, their feeding sites on the hosts and themale to female sex ratio were determined. Resistance to ticks between breeds was evaluatedbased on the cumulative log transformed counts of total ticks, fully engorged females andadult ticks and was analysed by the method of least squares. The results revealed that thecount of total ticks in Horro and Gurage (mean count of 5 ticks per month per breed) waslower than those of Abigar and Sheko (7 ticks per month per breed) (P< 0.001). The meancount of fully engorged females in Horro and Gurage cattle breeds was also lower (2 ticks permonth per breed) than Abigar and Sheko (3 ticks per month per breed) (P< 0.05). The meancount of adult ticks was the lowest in Horro (4 ticks per month per breed), followed byGurage (5 ticks per month per breed), Abigar and Sheko (6 ticks per month per breed) (P<0.01). Based on the three parameters, Horro and Gurage breeds were found to exhibitsignificantly higher resistance to ticks than Abigar and Sheko breeds. Packed Cell Volume(PCV) of the study animals was monitored monthly during the study period and negativecorrelation was found between tick burden and PCV levels in all the animals (P< 0.05).Infection with tick- transmitted parasites/ pathogens: Anaplasma marginale (84.2%), Babesiabigemina (87.1%) and Theileria mutans (54.2%) was confirmed serologically by indirect ELISA. Sera were also screened using indirect ELISA to investigate the animals for anti- Amblyomma variegatum antibody responses by using larval homogenate. Comparisons between antibody responses of each breed showed the presence of variations in IgG responses between the cattle breeds. Higher IgG response was found in Horro than the other three breeds (P< 0.05). The relationships between infestation with A. variegatum and the level of IgG were positive in Abigar (r = 0.3, P> 0.05), Gurage (r = 0.4, P< 0.05) and Sheko (r = 0.5,P< 0.05) breeds, while weak negative correlation (r = - 0.2, P> 0.05) was observed in Horro breed, indicating the possible role of IgG in the acquisition of host resistance to ticks.
  • No Thumbnail Available
    Item
    Evaluation of Coagulation Efficiency of Protein Extracts from Lupinus Albus L., Moringa Stenopetala (Baker F.) Cufod., Trigonella Foenum-Graecum L. and Vicia Faba L. for Water Purification
    (Addis Ababa University, 2020-08-08) Adele Neway; Feleke Adey
    Access to clean drinking water is a basic human right. However, an estimated 1.2 billion people across the world consume unclean water daily. An interest has been growing towards natural coagulants as the health and environmental concerns on conventional chemical coagulants are rising. Natural coagulants have the potential to serve as alternative water treatment agents. In this study, Lupinus albus, Moringa stenopetala, Trigonella foenum-graecum and Vicia faba protein extracts were evaluated as natural coagulants for water treatment. The protein extracts were purified from crude extracts using a protein purifier, and protein concentrations were determined by spectrophotometric method. Small volume coagulation efficiency tests were conducted on raw water taken from Legedadi water treatment plant. These were done using completely randomized design (CRD) experiment with settling times of 0 min (initial time), 90 min, 180 min and 270 min and, protein extract doses of 5 mg/L, 10 mg/L, 15 mg/L and 20 mg/L. Raw water as negative control and polyelectrolyte as positive control were also included. The optical density (OD) values were measured for all the samples. At 270 min and 20 mg/L, the coagulation efficiency percentages for Lupinus albus, Moringa stenopetala, Trigonella foenum-graecum and Vicia faba protein extracts were 71%, 89%, 12% and 67% in the water sample collected in April, 2019 respectively. Similarly, Lupinus albus, Moringa stenopetala and Vicia faba achieved 17%, 92% and 12% at 270 min settling times and 5 mg/L, 20 mg/L and 10 mg/L concentration in the water sample collected from August, 2019 respectively. Negative control (raw water) and polyelectrolyte (positive control) were also 6 − 10% and 89 − 94% at 270 min settling time in April and August, 2019 respectively. Among the four protein extracts, Moringa stenopetala showed the highest coagulation efficiency similar to polyelectrolyte. This study concluded that Moringa stenopetala protein extract can be used as natural coagulant for water purification in both sampling times.
  • No Thumbnail Available
    Item
    Microbial diversity and Molecular Biomonitoring for Efficient Treatment of Tannery Wastewater: Laboratory and Field- Scale Studies
    (Addis Ababa Universty, 2013-11) Feleke Adey; Assefa Fassil (PhD)
    This dissertation reports on culture- dependent and culture- independent characterization of microorganisms of from tannery wastewater, with special reference to degradation of selected retanning chemicals, In the culture- based study, four bacterial strains isolated ll'om a temporary storage site of composite tanncry wastewater were reported to grow and utilizc the retanning agcnts named as Basyantan AN and Retanal MD80 as their carbon and nitrogen sources. Ultra Performance Liquid Chromatography (UPLC) analysis of compounds in the retanning agents from batch cultures over a period of 14 days revealed an average of 18, 26 and 33% degradntion of the three detected peaks of Basyantan by isolate B45. The same isolate also showed an average of 34% degradation of Retana!' Kinetic studies conducted on this isolnte showed the dependence of growth on the concentration of Retanal as a substrate, with a maximum grO\\1h rate (Jlma,)of 1450 cells mr'.hr" and a half saturation constant (Ks) of 10.16 mg.r'. On the basis of 16S rRNA gene amplification, sequencing and phylogenetic analysis, the four isolates werc identified as Micrococcus luleus strain B lR, Brevibacleriulll pilyocalllpae strain B4500R, Lysinibacillus sphaericlls strain R 1902R and Enlerococcus gallina/'lllJl Strain R280 I R. Bench- scale study involving a sequencing batch reactor (SBR) run for 42 days for studying the biodegradation of Basyantan and Retanal revealed a pronounced degradation up to 100% regarding peak 2 of Basyantan. Dynamics of sludge microbial sub- communities as followed by T-RFLP showed the dominance of membcrs of the class Burkholderaceae and a less diverse community in the first five batches of the SBR run; which was then succeeded by members belonging to the phylum Bacteroidetes and classes Rhodocycalaceae, Rhodobacteraceae, Pseudomonadaceae and Bradyrhizobiaceae; with increased diversity towards the end of the run. Flow cytometric analysis of bacterial cells in the sludge was used to create pattcrns mirroring dynamics of bacterial community over the period of SBR run. The patterns were resolved in 30 sub, clusters eight of which wcre sOlicd and members identified. Correlation of the bacterial abundancc in thc sortcd sub- clusters with the measured abiotic data showed the prcsence of a strong (p< 0.0 I) positive correlation bctween degradation of Basyantan and Retanal with mcmbers of Bacteroidetes and Protcobactcria, indicating the key degradation role played by thesc members. Ficld- scale study on the structure and diversity of the microbial community in the sludge of the Anaerobic- aerobic reactors as well as the root area of a constructed wetland treating tannery effluent located in Modjo tannery was conducted using the 16S ribosomal RNA gene scquencing performcd for cach of the reactors. The results revealed a total of 31 different phylotypes with the dominant members belonging to FirllliclIIes, Bacleroidia, Proleobacleria, Sphingobacleria and S)'Ilergislia in the anaerobic and aerobic reactors. In the constructcd wetland, members of thc group C)'({l1obaCleria were also identified in addition to Firmicules, 13acleroidia and Proleobaclel'ia. Thc presence of members of groups that arc associated with reduction of sulfate and removal of chromium, nitrate and degradation of synthetic aromatic compounds indicates their implication in the current performance of the treatment system. Furthermore, physicochemical data (total Nitrogen, total Carbon, pH, Sulphate, Nitrate) have been recorded in the anaerobic, aerobic and constructed wetlands and analyses of these data elucidate the key factor structuring the observed microbial communities.
  • No Thumbnail Available
    Item
    Performance of Lab- scale Filtration System for Greywater Treatment and Reuse: A Case of College of Natural and Computational Science Campus, Addis Ababa University, Ethiopia
    (Addis Ababa University, 2020-07-04) Tusiime Anna; Zewge Feleke ; Feleke Adey
    Greywater management through treatment using filtration systems and reuse is one way to achieve water security in Ethiopia. The College of Natural and Computational Sciences (CNCS) campus of AAU is facing the problem of water shortage especially in the evening hours when normal water supply is cut off resulting into poor sanitation. Reusing greywater (GW) that comes from dormitories for non- potable uses is one of the options to supplement water supply. The pollution levels of GW is quite low as compared to black water. This quality allows greywater to be treated by simple treatment technology like filtration. The aim of this study was to evaluate the performance of a lab- scale filtration system for greywater treatment and reuse using sand and granular activated carbon as filter media. The specific objectives of this study were to: 1) Characterize the raw greywater generated at CNCS campus; 2) Compare the treatment efficiency of lab-scale filtration systems that use gravel + sand and gravel + sand + GAC; and 3) Evaluate willingness to use treated greywater for selected non-potable uses. Raw greywater quality was characterized by determining its physico-chemical and microbiological parameters in the laboratory. The treatment efficiency was determined by comparing the mean values before filtration and with those after filtration. The systems was examined for its efficiencies at different hydraulic retention times (HRT) (12, 24, and 36 hrs) and at different filter columns, one with gravel + sand and the other with gravel + sand + GAC operating at constant HLR (0.15m/h). The willingness to use treated greywater for selected non-potable uses was evaluated through interviews (using questionnaire). Results showed that the raw greywater was polluted and was above reuse standards except nitrates and Total phosphorus, therefore treatment was necessary. For both filter columns, the treatment efficiency of the system increased with HRT at 12 h and 24 h and later on it decreased at 36 h, except for EC and NH4-N, which decreased with increase in time. The removal of contaminants was significant higher (p < 0.05) at 24 h and with no significant different (p > 0.05) between filters except in removal of NH4-N. The pollution reduction was from 60.8 % - 100 % for selected parameters (pH, turbidity, EC, BOD, COD, NH4-N, NO3, TP, TC, and FC) in filter column B and from 47.2 % - 100 % for filter column A. The results also indicated that over 80% of the respondents were willing to use the treated greywater for selected non-portable uses, for the fact that the treated greywater was meeting the reuse standards. Thus, a filtration system is efficient and can be employed to treat GW for non-portable uses at CNCS to improve hygiene, sanitation and water shortage.
  • No Thumbnail Available
    Item
    Profiles of Physicochemical Characteristics, Antibiotic Residues, Antibiotic Resistance Genes and Bacteria Community Structure of Batu Tannery Wastewater Released to Little Akaki River
    (Addis Ababa University, 2020-06-10) Admassu Tesfaye; Assefa Fasil ; Feleke Adey ; G Love Nancy
    Tanneries produce one of the highest COD wastewaters afterusing large volume of water and different chemicals to produce semi-finished and finished leather products. In Ethiopia, most of the tannery wastewater is discharged directly into water bodies with little or no treatment. These days, different treatment systems are constructed to treat tannery wastewaters that necessitate research to evaluate the efficiency. To this end, a research was conducted on Batu Tannery wastewater treatment plant to evaluate the physicochemical characteristics, bacteria community dynamics, antibiotic residues and antibiotic resistance genes in the different stages of the tannery wastewater treatment plant. The raw tannery wastewater showed variable strength from time to time, andthe highest mean COD (7204+8) mg/l, ammonia-N (190±3.6) mg/l, total nitrogen (308±2)mg/l, and total chromium (22±2.7)mg/lwere observed in April samples. The range of pH remains between 8.0 and 9.0 in raw tannery wastewater and 7.2 and 8.6 in the final effluent. The tannery effluent affected the physicochemical characteristics of the downstream river water of Little Akaki, except temperature and pH. The tannery effluent released to the Little Akaki River caused an increase in the physicochemical values by an average of 3.8%, 9% and 9.5% for COD; 23%, 10.4% and 12.5% for TN; 13.5%, 18.4% and 14.8% forammonia_N; and 31.5%, 28% and 52.8% for total chromium in the November, February, and April samples, respectively. However, only the COD, sulfate and total chromium cause significant (p < 0.05) difference in the downstream river water after tannery effluent was released. 16S rRNA amplicon-based bacterial community analysis from the treatment plant revealed that Firmicutes (48.5%), Bacteroidetes (32.6%) and Proteobacteria (11.5%) were the most represented bacterial phyla across the treatment plant. At the genus level, the dominant genera were Clostridium (15%), Synergistes (5%), Psychrobacter (4%), Acinetobacter (2.5%), Bacteroidetes (1.8%), Anaerovorax (1.3%), Arcobacter (1.3%) and Shewanella (1%). Most of the core bacteria communities in the tannery wastewater were common signatures of gastrointestinal bacteria of ruminants. Some of the core bacteria arepotential pathogens tohuman including the Clostridium, Acinetobacter, Arcobacter and Shewanella. Antibiotic residues and antibiotic resistance genes were detected in the tannery wastewater. The antibiotic residues of tetracycline, oxytetracycline, erythromycin, penicillin G, trimethoprim, sulfadiazine, sulfadoxine, sulfamethoxazole and ciprofloxacin were present in all samples of the tannery wastewater, but penicillin V, amoxicillin, streptomycin, ampicillin and vancomycin were not detected in the same samples. The antibiotic resistance genes tet(A), tet(O), tet(M), erm(B), Sul(I), Sul(II) and Otr(A) were also detected in the tannery wastewater samples. An assessment on the use trend of antibiotics in livestock indicated that antibiotic contamination to tannery wastewater was highly likely to come from the misuse ofantibiotics in livestock disease treatment.
  • No Thumbnail Available
    Item
    Recovery and Removal of Phosphorus via Struvite (MgNH4PO4. 6H2O) Crystallization in Fluidized Bed Reactor from Domestic Wastewater
    (Addis Ababa University, 2021-09-20) Tamru Eskinder; Kebede Shimelis ; Feleke Adey
    Phosphorus is a vital nutrient for food production which is produced from limited, non-renewable resource called phosphate fossil. At the present rate of utilization, the world’s reserve of phosphate fossil will be exhausted soon. However, wastewater contain huge amount of phosphorus which can be recycled to reduce depletion of phosphate fossil. Beside this fact, phosphorus should be removed from wastewater before discharging it into water bodies, to avoid eutrophication. One of the promising methods of phosphorus recovery in to useful end product is struvite crystallization. The present study focuses on recovery of phosphorus via struvite crystallization from domestic wastewater in fluidized bed reactor. Response surface experimental design was implemented to optimize process parameters such as pH (8 – 12), ammonium to phosphate molar ratio (1 - 4), magnesium to phosphate molar ratio (0.5 – 2.5) and reaction time (1hr. – 5 hr.) using model solution. The optimized value for pH, ammonium to phosphate molar ratio, magnesium to phosphate molar ratio and reaction time were found to be 10, 2.9, 1 and 4 hr. respectively. Under this optimized value 81% and 74% phosphorus removal efficiency was achieved from model solution and domestic wastewater respectively. Similarly, 1.29 and 2.9 gram of struvite yield was obtained from 10 litter of model solution and domestic wastewater respectively. Although higher amount of struvite yield (2.9 gram) was obtained from domestic wastewater, struvite crystal purity was lower (68.7%). Elemental composition of crystals precipitated under optimized condition indicate that octahedral struvite crystals was the dominant compound which was further identified by scanning electron microscope, Fourier transform infrared spectroscopy and X-ray diffraction. This study also investigated the potential of Basaka Lake water as locally available magnesium source for struvite crystallization. Seventy nine percent (79%) and sixty eight percent (68%) phosphate removal efficiency were achieved from model solution and domestic wastewater respectively by employing Basaka Lake water as a source of magnesium. Overall, struvite crystallization from domestic wastewater is a sustainable eco-friendly approach for removal of phosphorus via struvite which can be used as fertilizer in agricultural sector.