Adsorption of chromium from electroplating wastewater using activated carbon developed from water hyacinth.

Industrial wastewater polluted with high concentrations of Cr is commonly discharged into water resources without proper treatment. This gives rise to the deterioration of water quality and imposes adverse effects on public health. Therefore, this study is aimed at removing Cr from electroplating wastewater using activated carbon produced from water hyacinth under a full factorial experimental design with three factors and three levels (pH,2,5 and 8, adsorbent dose 0.5,1and1.5 in 100 mL and contact time 30, 60 and120 min). A phosphoric acid solution of 37% was used to activate the carbon, which was then subjected to thermal decomposition for 15 min at 500 °C. The activated carbon was characterized by the presence of a high surface area (203.83 m2/g) of BET, cracking of adsorbent beads of SEM morphology, amorphous nature of XRD, and many functional groups of FTIR such as hydroxyl (3283 cm-1), alkane (2920 cm-1), nitrile (2114 cm-1) and aromatics (1613 cm-1). The minimum Cr adsorption performance of 15.6% was obtained whereas maximum removal of 90.4% was recorded at the experimental condition of pH 2, adsorbent dose of 1.5 g/100 mL, and contact time of 120 min at a fixed value of initial Cr concentration of 100 mg/L. Similarly, the maximum Cr removal from real electroplating wastewater was 81.2% at this optimum point. Langmuir's model best described the experimental value at R2 0.96 which implies the adsorption is chemically bonded, homogeneous, and monolayer. Pseudo-second-order model best fits with the experimental data with R2 value of 0.99. The adsorbent was regenerated for seven cycles and the removal efficiency decreased from 93.25% to 21.35%. Finally, this technology is promising to be scaled up to an industrial level.

Evaluation of the physicochemical properties of honey produced in Doyogena and Kachabira Districts of Kembata Tambaro zone, Southern Ethiopia.

This study was conducted to evaluate the Physicochemical properties of honey produced in Doyogena and Kachabira districts, of Kembata Tambaro Zone, Southern Ethiopia. For the laboratory evaluation a total of eighteen (18) honey samples were collected. Of the total of 18 honey samples, 12 (6 from highland and 6 from midland) were purposively taken directly from the beekeepers from frame beehives and 6 honey samples were randomly taken from six retailor shops. The main parameters analyzed were color, moisture, electrical conductivity, ash, reducing sugar, fructose to glucose ratio, glucose to water ratio, fructose, glucose, fructose plus glucose, sucrose, Hydroxyl methyl furfural, power of hydrogen and free acidity. These parameters were evaluated in the Holetta bee research center laboratory and results were analyzed by Statistical analysis system software. The result of laboratory work indicated that the mean value of moisture, electrical conductivity, ash, reducing sugar, fructose to glucose ratio, glucose to water ratio, fructose, glucose, fructose plus glucose, sucrose, Hydroxyl methyl furfural, power of hydrogen and free acidity was, 18.83 ± 0.69 g/100g, 0.58 ± 0.03 mS/cm, 0.25 ± 0.02 g/100g, 68.55 ± 0.56 g/100g, 1.05 ± 0.03, 1.78 ± 0.08, 34.22 ± 0.55 g/100g, 32.61 ± 0.70 g/100g, 66.83 ± 0.44 g/100g, 2.54 ± 0.40 g/100g, 3.42 ± 1.95 mg/kg, 4.03 ± 0.21 and 13.39 ± 1.43 meq/kg respectively. There was a significant difference (P < 0.05) between districts in terms of moisture and power of hydrogen. Significant difference (P < 0.01) was declared between agro-ecologies in terms of the moisture, glucose to water ratio and free acidity. Moreover, a significant difference (P < 0.05) was seen between agro-ecologies concerning electrical conductivity and ash. There was a statistically significant difference (P < 0.01) between the honeys of the retailer shop and farm gate sources concerning moisture content, electrical conductivity, ash, reducing sugar, glucose to water ratio, sucrose, Hydroxyl methyl furfural and free acidity. The result of the study indicated that all the physicochemical parameters of honey evaluated lie within the range of national and international standards. Because of the good quality of honey of the study area, it is advised to exploit the potential for export market with better intervention.

Assessment of Major Causes of Calf Mortality in Urban and Periurban Dairy Production System of Ethiopia.

A cross-sectional calf mortality study was conducted in urban and periurban dairy farms in Addis Ababa, special zones of Oromia and Amhara regions in July and August 2015. The objectives of the study were to estimate the annual mortality and to assess the major causes of calf mortality in the dairy farms. One-year retrospective data on calf mortality were collected from 330 farms by face-to-face interview using the pretested and structured questionnaire format and direct observation of farm practices. A logistic regression analysis was performed in order to identify the predictor variables associated with early calf mortality. Data were analysed using Statistical Package, Stata SE for Windows, version 12.0. The annual mean calf mortality from birth-to-weaning was reported as 18.5% (95% CI: 12.6, 24.3%). The prenatal loss due to fetal death and stillbirth was 10.1% (95% CI: 6.7, 13.6%). The overall annual loss due to fetal death and calf preweaning mortality was 26.7% (95% CI: 21.2, 32.2%). Age-specific mortality declined with increased age, and the highest mortality was recorded during the first month of life extending up to the third month of age. Disease was the most important causes of calf mortality (73.2%). Among the diseases, diarrhea (63%) and respiratory disorders (17%) were the important causes of calf mortality. Malpractices in calf management were identified, including restricted colostrum and milk feeding, poor care and supplemental feeding, and poor health management. Interventions in dairy cattle health and farm husbandry are recommended to control calf mortality.