The effects of time and carbon height on the removal of chromium from wastewater were investigated in fixed down flow adsorption columns containing mango seed shell activated carbon (MSSAC) for the purpose of converting the waste to wealth. The Hutchin's bed depth service time (BDST) model was used to study the columns performance at 10% and 90% breakthrough concentrations. The BDST model constants were determined. The BDST equation obtained at flow rate of 1.61l.hr and influent chromium concentration of 3.151mg/L was used to predict the adsorbent performance at other flow rates and initial chromium concentrations. Results obtained revealed that there was a gradual decrease in the percentage of chromium adsorbed with time; the percentage adsorbed became zero at 72.33, 467.5 and 572 hours respectively for 3cm, 3.5cm and 4cm carbon heights. The breakthrough curves for chromium adsorption deviated from the characteristic S-curve for most dynamic studies because 100% removal of chromium was not attained even at the commencement of the column operation because of the high initial concentration of the adsorbate adopted in this study. It was observed that for a given breakthrough concentration, the service time decreased with increase in both flow rate and initial chromium concentration. Chi-square test performed on the developed BDST models revealed the reliability of the models for the prediction of the columns performance particularly at lower breakthrough concentrations. It was therefore recommended that MSSAC can be used for the removal of chromium from wastewater in adsorption columns; however there is the need for pilot studies on live wastewater to investigate the effect of interference.
The assessment of safety hazards is fundamental to an effective risk management in any industry. Food and beverage production involves a variety of industrial processes with associated hazards. Effective safety practices are used to reduce workplace hazards and promote safety in the work environment. This paper evaluated safety hazards and safety practices in the food and beverage industry (FBI) in South-South, Nigeria. A structured questionnaire designed in accordance with World Health Organization standard was administered to a total of 144 workers, out of which 134 (93.0%) were completed and returned. The questionnaire was fashioned to extract information on types of hazards, awareness of safety hazards, implementation of hazards and risks control measures and the effectiveness of safety hazards and risk management programmes in the food and beverage industry. A modified four-point Likert Scale was used to analyze and evaluate the questionnaire. A Proportional Importance Index (PII) was used to rank each factor variable in the questionnaire. The study identified the major hazards in the FBI as working at height (with PII = 3.3, respondents = 91%); high voltage areas (PII = 3.1 and respondents = 90%), loud noise (PII = 3.0, respondents = 80%), machines and equipment vibration (PII = 2.8, respondents = 69%) and faulty machines and equipment (PII = 2.7, respondents = 65%). The level of awareness on safety hazards amongst the workers was statistically significant (p < 0.05, 95%CI; PII = 3.1 - 3.6). The outcome of intervention showed that FBI-2 improved from 79.62% to 96.82%, FBI-3 improved from 89.81% to 96.18%, FBI-4 improved from 78.34% to 95.54% on worker’s knowledge on the assessment of hazards and risk in the FBIs. There was effective implementation of safety hazards and risks management programmes and controls in the FBI. Administrative control measures are used to reduce hazards and workers make adequate use of personnel protective equipment. There is need to evaluate the risks associated with identified high ranking hazards and develop a risk management framework for the industry based on ISO 31000 and other relevant safety regulations and guidelines.
This paper compared the differences and similarities in the rainfall intensities predicted by four standard IDF equations for return periods between 5 and 40 years and for storm durations between 15 and 30 minutes. The empirical models employed for comparison on the development of standard IDF equations using historic data for Benin, Calabar, Port Harcourt, Onitsha and Warri meteorological stations, all in Southern Nigeria were available in literature. The strength and weakness of the different models were assessed using the mean ± standard deviation as range between intensities estimated for 5 and 40 years, and percent relative error between the observed and predicted rainfall intensities as performance criteria. The results obtained showed that there were significant differences in the rainfall intensities as predicted by the equation types. However, the IDF types-1 and 2 equations displayed lower range values in intensities for all returned periods. Types-1 and 2 equations predicted the lowest relative error of less than or equal to 6% in all stations considered. Because IDF studies are associated with hydrologic extremes, both types-1 and 2 equations are therefore recommended for hydrologic design of flood control structures. The study has advanced the understanding of the equations and further insight in their utility as hydrologic design tools.
The hospital is a high risk environment for the transmission of infections to health care workers, visitors, patients and the surrounding community. Healthcare workers are exposed to a variety of hazards which predisposes these “indispensable carers” to various life threatening infections and diseases. This study is aimed at evaluating the occupational hygiene and infection control practices in Federal Medical Center (FMC) Owerri and FMC Yenayoa, both located within southern Nigeria. Descriptive cross sectional study using a structured questionnaire and walk-through safety checklist was employed. A total of 379 healthcare workers were selected through disproportionate stratified sampling from the two facilities. The questionnaires were self-administered and analyzed using SPSS Version 22.0. Frequencies, chi-square were computed and multivariable logistic regression analysis was used to identify the predisposing factors to which health workers are exposed; 60.7% of respondents were male, dominant age group; 30 – 39yrs, nurses represented a larger proportion (34.8%) of healthcare workers in this study; 51.7% and 48.3% of respondents in FMC Yenagoa and FMC Owerri respectively had a good knowledge of hazards and controls. There was a significant difference with chi-square as, 9.710 p-Value <0.008. Good level of attitude was 44.7% in Owerri and 21.2% in Yenagoa, chi-square 18.295 p-Value <0.001. Overall level of occupational hygiene and infection control practices was poor in both facilities. Health care workers had a very high level of exposure to ergonomic hazards (88.9%) and biological hazards 47.6% in Owerri and 55.3% in Yenagoa. Nurses were 5 times more at risk of ergonomic hazards (95%CI) – 5.96 (2.19–16.24) p-Value < 0.001, while Medical Laboratory scientists were 5 times more at risk of chemical hazards (OR = 5.98, 95CI: 3.05–11.69, p-Value <0.001). The checklist revealed that both facilities were of imminent high risk category. Health care workers at FMC Yenagoa had higher exposures to all five categories of hazards than FMC Owerri. Working in FMC Owerri predisposes workers to higher health hazards than in FMC Yenagoa. There was better administrative controls including trainings and immunizations in FMC Yenagoa than in FMC Owerri.
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