Investigating the Rate of Uptake of TPH, TOC, Organic Matter and Some Heavy Metals by Melon Grass in a Crude Oil Polluted Soil in the Tropical Region
Author(s): Modestus Chidera UWAZIE, Okechukwu Dominic ONUKWULI, Akinpelu Kamoru BABAYEMI, Jonah Chukwudi UMEUZUEGBU
Abstract: This study was on the risk management analysis of labour and equipment for effective production output in quarries, in Ondo, Oyo and Ogun States of Nigeria with aim of identifying the work hazards encountered by quarry workers, assessing the level of risk faced by quarry worker’s, examining the likelihood of occurrence of hazards at quarry workplace and precautionary measures put in place. Sixty quarry workers were randomly selected across both skilled and unskilled division and were administered with a structured questionnaire to know the various hazards and hazard management during their operations in quarry. Data collected were analysed using descriptive statistics, frequency tables and charts. Potential Hazards faced by respondents according to the analysis are electric shocks (69.23%), noise pollution (86.15%), dusts impact (86.15%), fly rocks during blasting (52.31%), excessive workload (73.85%), long hours of work (80.00%), slips and trips (93.85%) and wet floors/road (50.77%). Victims include the community people (64.62%), operators (69.23%), visitors (56.92%) and new workers (63.08%). Risk control measure mostly used was first aid facilities and this was adequate. Workers are also likely to experience fly rocks (26.2%), long hours of work (49.2%), wet floors/road (33.8%), hydrocarbon fuel spillage (52.3%), runoff from sites (33.8%) and soil erosion to farmlands (32.3%), dust impact on visuals (55.4%). Quarry workers (64.6%) attest they do not attend safety seminars because they are not given by the management. A proportion of 24.6% of the quarry workers has not been involved as causalities of any hazard despite the regular (always) breakdown of workers (40.0%) at the workplace. The results of the water analysis revealed the level of heavy metals like Lead (Pb), Cadmium (Cd), Magnesium (Mg) and Chromium (Cr) are higher than the permissible limit recommended by WHO; hence the water sources pose a great threat to the health of the people and workers.
Dynamics of Polyaromatic Hydrocarbon Degradation Under Monitored Bioattenuation System
Author(s): Chioma Bertha EHIS-ERIAKHA, Vincent Aizebeoje BALOGUN
Abstract: Bioattenuation encompasses processes that lead to reduction of the mass, toxicity, mobility, or volume of contaminants without human intervention. This study was designed to determine the dynamics of polyaromatic hydrocarbon degradation under a monitored bioattenuation bioremediation system. Preliminary analysis was conducted to determine the extent of pollution by chemical analysis and to enumerate the microbiological population in the sample by standard microbiological methods. The identities of the hydrocarbon degrading bacteria population were ascertained using 16SrRNA molecular typing algorithm. The experimental duration was 35 days and the microcosm was monitored at weekly interval under a controlled system. A 4% spike in crude oil level was conducted to increase the concentration of PAH in the sample to 989.1 mg/kg. Total viable heterotrophic and hydrocarbon degrading bacteria populations were CFU X 108g and the dominant class of microbes was Grammaproteobacteria and genus Pseudomonas. The overall degradation rate was recorded at 52%. Anthracene was 100% degraded while benzo(b)fluoranthene, fluorine and pyrene had above 50% removal. All other PAHs present in the sample experienced some level of degradation except acenaphthylene, dibenz (a,h)anthracene and chrysene which increased slightly in concentration. The natural attenuation process was effective in degradation of the pollutant within the experimental period.
Evaluation of Thermo-Mechanical Properties of Insulating Refractory Bricks Made from Indigenous Clay Mixed with Gmelina Seed Shells Particulates
Author(s): Eugenia Obiageli OBIDIEGWU, Ezenwanyi Fidelia OCHULOR, Henry Ekene MGBEMERE
Abstract: Due to scanty or lack of good insulating refractory materials in commercial quantity, most of the manufacturing and processing industries in developing countries such as Nigeria depend mainly on imported insulating refractory bricks to line their furnaces. This is to improve energy efficiency and reduction in energy loss. Despite the abundant resources of fireclay in the country for the production of insulating refractory bricks, these industries depend mainly on the imported refractory bricks. This leads to the high cost of the final product. This work studied the characteristics of insulating refractory bricks from Nigerian clay and Gmelina seed shell particulate. The chemical composition of the raw materials were analysed using Atomic Absorption Spectrometer. The samples were obtained by mixing both clay and Gmelina seed shells such that the composition of the Gmelina seed were 0 %, 20%, 25 %, and 30 %. The compressed bricks were dried and sintered at a heating rate of 2.5oC/min to temperatures ranging from 950oC to 1100oC at 50oC intervals, The results of the physical, thermal and mechanical characterisation showed that when Gmelina content were between 25-30 wt% at temperatures between 1000oC to 1100oC, the porosity increased from 26.1 – 72.4%, bulk density decreased from 3.4 – 1.5 g/cm3, Cold crushing strength increased from 126 – 1162 kN/m2 and thermal conductivity decreased from 0.28 – 0.12 W/mK. These results indicate that Gmelina particles helped to produce bricks with enhanced insulating properties. In conclusion, this work discovered a new refractory material (Gmelina seed shells which are in abundance in Nigeria). This can increase the physical, thermal and mechanical characteristics of a refractory brick. Also, this work could benefit the manufacturing and pottery industries, and in the production of refractory materials.
Reliable Estimation of Compressive Strength of Sandcrete Blocks in the Context of Limited Test Samples
Author(s): Stephen Adeyemi ALABI, Tolulope Abidemi ALABI
Abstract: Sandcrete blocks are the primary material used in Nigeria as partition walls and sometimes as load-bearing walls. The quality of the constituent materials, the curing methods, and the mixing methods are known to influence quality. However, the quality of blocks is usually evaluated using the compressive strength, fB. However, different studies have shown that there is no unique fB value for block due to high inherent variability. The uncertainty associated with fB is reportedly evaluated using a traditional statistical method that requires a significant amount of test results. Extensive data are usually not available due to the practical challenges in the preparation of the compression test sample. This study, therefore, utilizes the Markov chain Monte Carlo (MCMC) Bayesian probabilistic approach to solve the challenges of restricted testing data as well as the uncertainty inherent in the test results to ensure the quality of the block produced. The framework begins with the development of a general probability model called the likelihood function to evaluate the marginal posterior probability based on a limited number of fB data. The mean and coefficient of variation (COV) values of the MCMC generated sample and the direct measurement of fB were 0.94 N/mm2 and 13.10%, and 1.03 N/mm2 and 19.20% respectively. The difference between the average values of the samples from the MCMC approach and the direct measurement is 0.09 N/mm2, representing a relative difference of 8.77%. On the other hand, the COV difference is 6.10%, showing a considerable variation of 31.80%. The slight difference between the average values shows that the mean values are in good agreement with each other, inferring that the probabilistic MCMC-based method performs excellently. It can be concluded that integrating prior knowledge, limited compression test data, and Bayesian inference methods into the design process can contribute to a more reliable structure even with higher permissible stress. Factors such as the degree of uncertainty in the design of walls and the consequences of the collapse of walls or structures can be logically integrated into the design specifications.
Methyl Ester Fatty Acids Profiles of African Mahogany Biodiesel Produced at Varied Molar Ratios, 0.50% NaOH Catalyst Concentration, Constant Time and Temperature
Author(s): Zamani Donald ISHAYA, Gyang Yakubu PAM, Dangana Mallam KULLA, Abubakar Ishaq JUMARE
Abstract: World environmental degradation and energy supplies insecurities occasioned by climate change, air pollution and coronary diseases has contributed to the increased interest in new energy sources. This study focused on the production and characterization of the methyl esters fatty acid (MEFA) of African Mahogany (AM) at varied oil to methanol molar ratios (MR) of 1:6, 1:9 and 1:12, while other key parameters of 0.50 % NaOH catalyst concentration at 60 o C, for 1-hour were kept constant. The oil from the African mahogany seed kernel was extracted using a Mechanical expeller and a yield of 44.88% – by weight was obtained. AM percent free fatty acid was reduced from 17.39 to 0.46 mg (KOH)/ g (of the oil) by 4-runs of H2SO4 acid esterification. This was followed by alkaline (NaOH) transesterification conducted and the biodiesels were produced at the varied oil to methanol molar ratios. The chemical composition cum profile of the produced biodiesels were determined using the gas chromatograph and mass spectrometer (GCMS). The results indicated increasing yields of MEFA from AM at molar ratio (MR) of 1:6 was 55.99 %, then AM. at MR of 1:9 was 65.97 %, and AM. at MR of 1:12 to 79.48 %. Similarly, the principal composition of Octadecenoic acid methyl ester increased from 16.55% in crude AM oil to 30.22 %, 39.89 % and 46.62 % in the biodiesel produced as the molar ratios were increased from 1:6 to 1:12. Thus, a mathematical model y = 1.763×2 + 1.167x + 46.604 (MR = 1 < x < 5) having the predictability R² = 1 for AM feedstock was established.
Assessment of Selected Engineering Properties of Sandcrete Blocks from Akinyele Local Government Area, Oyo State
Author(s): Ajibola Ibrahim QUADRI, Mubaarak ABDULHAMEED
Abstract: Previous works of research have indicated that quality standards are being ignored by actors in Nigerian Construction industry. This paper investigated and reported the strength properties of sandcrete blocks produced in Akinyele Local Government Area of Oyo State, Nigeria. A total of 30 blocks were acquired, three (3) blocks each of 6″ (450 mm × 150 mm × 225 mm) and 9″ (450 mm × 225 mm × 225 mm) were collected from five (5) industries randomly. Soil samples were also collected and tested. The tests carried out were, sieve analysis, specific gravity, compressive strength, and water absorption rate. The compressive strength of all the blocks was below standard requirement as their values range between 0.22 N/mm2 and 0.46 N/mm2 for the (9″) blocks, 0.3 N/mm2, and 0.6 N/mm2 for the (6″) blocks. It could be concluded that sandcrete blocks from the selected industries in the Local Government Area did not meet 2.1 N/mm2, the minimum strength required for non-load bearing walls. Therefore, they should not be used as non-load bearing units. It is recommended that professional bodies and government agencies responsible for quality assurance of building units should enforce compliance of block industries with the minimum required specifications.
Cyanide Biosorption from Aqueous Solution by Iron-impregnated Palm Kernel Fibre Adsorbent: Equilibrium, Kinetics and Optimization
Author(s): Michael Sunday OLAKUNLE, Olusegun Ayoola AJAYI, Francisca Unoma NWAFULUGO
Abstract: Cyanide poisoning in water bodies often results from human activities via cassava processing, which is highly undesirable in water bodies. This work describes the preparation of palm kernel fibre ash (PKFA) adsorbent via wet beneficiation, calcination and impregnation with Iron (II) nitrate for cyanide adsorption from its aqueous solution. The raw palm kernel fibre (PKF), calcined PKFA and Fe2+ impregnated PKFA (Fe-PKFA) were characterized using a scanning electron microscope (SEM) and Fourier Transform Infrared (FTIR), whereas UV spectrophotometer was used to monitor the cyanide concentration. Box-Behnken experimental design method of the response surface methodology (RSM) was employed to study the effect of temperature, contact time, adsorbent dosages, and initial concentration on the adsorption efficiency of the adsorbents at fixed pH 7. Optimal adsorption efficiency of 85.43% was obtained with 60 ppm initial concentration, 3 g of calcined Fe-impregnated adsorbent dosage at 42 minutes contact time and temperature of 35 oC. The developed model for the adsorption process gave R2 value of 0.9985 which shows that the model is significantly high, and there was good agreement between the experimental and simulated values. The adsorption process was best described by the pseudo-second order and intra particle diffusion kinetic models. The Temkin adsorption isotherm gave the highest regression coefficient and the variation of adsorption energy was 14.47kJ/mol which indicated an exothermic process. The results revealed that the Fe2+ impregnated PKFA adsorbent can serve as a good and sustainable adsorbent for cyanide biosorption from wastewater.
Development of Mathematical Modelling for Predicting Spray Mass Flux on Tree Canopies
Author(s): Buba Baba SHANI
Abstract: This study is to develop a mathematical model that could theoretically estimate spray mass flux of spray materials of a selected sprayer at different operating conditions in an orchard farm. Investigation were conducted and data were collected on randomly selected orchard tree of population of (n)100. A paired t-test was conducted and the result revealed that the calculated t- values (0.769) is less than the table value (3.25) at 0.01 level of significance, with (r 2) of 0.98, the Root mean Square Error (RMSE), the standard deviation (S d) 0.059 and 0.0065 respectively. All the inputs variables of the model developed indicate high degree of precision with which the treatment values were compared and are a good index of reliability of the experimental results and the sensitivity of developed predicted models to change in the constituent independent variables is negligible and not significant.
Development of Model Systems Using Aspen Plus for Syngas Production from Waste via Gasification
Author(s): Henry Ikechukwu ILEHOMON, Patience Oshuare SEDEMOGUN
Abstract: The need for Energy is paramount to human existence. Biomass Gasification utilizes the process of synthesis gas “Syngas” production which can be used as an alternate to conventional means of energy generation. This Research encompasses the development of model systems using ASPEN Plus for syngas production from waste via gasification. The feed stock proximate and ultimate analysis used was obtained from previous authors whose research was done within Minna, Niger state. These obtained data were used to develop a model system using ASPEN PLUS simulation software and the Syngas composition H2, N2, CO, CO2, CH4. From table 5, model 3 and 4 of the Syngas composition where compared with the effective Syngas range of values, H2– 2-5%, CO- 35-40%, H2– 20-40%, CO2– 25-35%, CH4– 0-15%, which was within the range for effective Syngas. The obtained simulated Results show that the waste generated from these locations can generate an effective amount of Syngas that can be used for Energy Generation.