josiah ayotamuno | RIVERS STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY (original) (raw)

Papers by josiah ayotamuno

Civil and Environmental Research, 2015

World Applied Sciences Journal

Compositional distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in Nigerian oil... more Compositional distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in Nigerian oil-based drill-cuttings have been studied for evidence of petrogenic and/or pyrogenic effects with recommendations for the strict enforcement of the ban on the use of oil-based mud in drilling by government regulatory agencies and prior bio-treatment of the drill cuttings before final fate. Laboratory analysis of the drill cuttings with a Gas Chromatogram Model 6890N equipped with a flame ionization detector showed that the total initial PAHs concentration of the drill-cuttings was 223.52mg/kg while the initial individual PAHs concentrations ranged from 1.67 to 70.7 mg/kg, dry weight, with a 90% predominance of the combustion-specific 3-ring PAHs. The ratio of anthracene to (phenanthrene + anthracene) = 0.31 was found to be greater than the 0.10 pyrogenic source-criterion for PAHs fraction of molar-mass 178g/mol while the ratio of fluoranthene to (pyrene + fluoranthene) = 0.40 was found to...

African Journal of …, 2011

... present study, therefore, aimed to investi-gate the potentials of saline (that is, brackish) ... more ... present study, therefore, aimed to investi-gate the potentials of saline (that is, brackish) water to enhance the bioremediation of a sludge containing hydrocarbons. ... N, 7014'E). The fresh water was collected from Orashi River (4057'N, 6031'E) and the saline water from Elelenwo ...

The Environmentalist, 1990

Management of Environmental Quality: An International Journal, 2004

Until recently, Port Harcourt was known as the "garden city of Nigeria" because of its neatness a... more Until recently, Port Harcourt was known as the "garden city of Nigeria" because of its neatness and the overwhelming presence of vegetation and flowers all over the metropolis. But today, the presence of piles of refuse dotting the entire city may have turned Port Harcourt rather to a "garbage city". Indiscriminate dumping of wastes -industrial, commercial and householdsuch as food waste, paper, polyethene, textiles, scrap metals, glasses, wood, plastic, etc. at street corners and gutters, is still very common. The situation is so bad that traffic flow is obstructed, while there is likelihood that leachates from such dumps, after mixing with rain water, have the potential to contaminate drinking water. The basic solid waste management processes of collection, transport, segregation and final disposal appear to be very inefficient. This research carefully assessed the present system of solid waste management in Port Harcourt, with the aim of identifying the main bottlenecks to its efficiency and the way forward. The subject matter of solid waste management is the main object of discussion throughout this article.

Journal of Hazardous Materials, 2000

Applied Energy, 2009

ABSTRACT The rates of energy that moving vehicles dissipate to road surfaces as well as noise emi... more ABSTRACT The rates of energy that moving vehicles dissipate to road surfaces as well as noise emissions and their propensities for pitting (and hence their repair costs per year) all depend upon the structural properties of these surfaces. Thus, to increase the strength of bituminous concrete (i.e. a typical flexible road-surface) has been one of the major recent aims in highway engineering. The present study explored techniques that will increase these strength properties by modifying the material, using rubber latex, through rubberization and hence, improve the strength of the flexible trafficked surface when in contact with vehicles. At the optimal design asphalt (i.e. bitumen) content of 4.68%, the successive addition of various percentages of the rubber latex produced a design value of 1.65% rubber content, which increased the stability of the roadway from 1595 to 2639Â N (i.e. an 65.5% increase) and the density from 2447 to 2520.8Â kg/m3 (i.e. a 3.02% increase). This shows that the addition of rubber latex to bituminous concrete (a flexible road-surface) increased sustainability and the strength (in terms of stability and density). Similarly, the air voids and voids in the mineral aggregate (VMA) were reduced by introducing latex from 4.22% to 3.45% (i.e. a 17.06% reduction) and 16.25% to 13.43% (i.e. an 17.4% reduction), respectively. Whereas, the reduction in voidage volume added strength to the bituminous concrete by increasing its stability and density, the reduction in VMA had no positive impact on the strength properties of the flexible road-surface.

International journal of food, …, 2009

The potentials of bioaugmentation and composting as bioremediation technologies for the removal o... more The potentials of bioaugmentation and composting as bioremediation technologies for the removal of polycyclic aromatic hydrocarbons (PAHs) from oil-field drill-cuttings have been compared. From a mud-pit close to a just-completed crude-oil well in the Niger Delta region of Nigeria, 4000 g of drill cuttings was obtained and homogenized with 667 g of top-soil (to serve as microbes carrier) in three separate reactors (A, B and C). The bioaugmentation of indigenous bacteria in the mix was done by adding to reactors A and B a 20-ml working solution (containing 7.6x10 11 cfu/ml) of pure culture of Bacillus and Pseudomonas, respectively, while a 20-ml working solution (containing 1.5x10 12 cfu/ml) of the mixed culture of Bacillus and Pseudomonas was added to reactor C. The bio-preparation was added to each reactor (excluding the control) every two weeks for six weeks. The composting experiment was conducted in a sufficiently well lagged, very low thermal conductivity, 10-litre reactor in which 4000 g of drill cuttings, 920 g of topsoil and 154 g of farmyard manure and poultry droppings were homogenized. Mixing and watering of the set-ups was done at 3 days interval under ambient temperature over a period of six weeks. Results showed that the initial individual PAHs concentrations of the drill cuttings ranged from 1.67 to 70.7 mg/kg dry weight, with a predominance of the combustion-specific 3-ring PAHs (representing 90% of a total initial PAHs concentration of 223.52 mg/kg). This indicates that anthropogenic sources of the PAHs were more of pyrogenic than petrogenic. There were far more PAHs reductions at the end of the experiment with the bioaugmentation method than with the composting method particularly at the initial and final stages of the experiment, which indicates that the performance of the bioaugmentation method was better than the composting method. Maximum composting temperature observed was 54 o C. Considering the impact of the environmental bacterial isolates (i.e. Bacillus and Pseudomonas) used to degrade the PAHs of the drill cuttings, the Pseudomonas degraded the 3-ring and 4-ring PAHs relatively better than did the Bacillus. However, the Bacillus degraded the 5-ring PAHs relatively better than the Pseudomonas only in the first two weeks of treatment. It was also observed that the cometabolism of the 3-or 4-ring PAHs could not have a synergetic effect on the 5-ring PAHs when the mixed culture was tested. Instead, this resulted in the limited degradation of the 5-ring PAHs particularly in the fourth week of the experiment.

African Journal of …, 2009

The effectiveness of 2 bacterial isolates (Bacillus subtilis and Pseudomonas aeruginosa) in the r... more The effectiveness of 2 bacterial isolates (Bacillus subtilis and Pseudomonas aeruginosa) in the restoration of oil-field drill-cuttings contaminated with polycyclic aromatic hydrocarbons (PAHs) was studied. A mixture of 4 kg of the drill-cuttings and 0.67 kg of top-soil were charged into triplicate plastic reactors labeled A1 to A3, B1 to B3, C1 to C3 and O1 to O3. These were left quiescent for 7 days under ambient conditions before adding to reactors A1 -A3 and B1 -B3 respectively, 20 ml working solution of pure cultures of Bacillus sp and Pseudomonas sp each of cell density 7.6 x 10 11 cfu/ml. Another 20 ml working solution containing the both cultures at cell density 1.5 x 10 12 cfu/ml was added to reactors C1 -C3. The working solution was added to each reactor (excluding the controls, O1 -O3) every 2 weeks mixing and watering of the set-ups was done at 3 days interval under ambient temperature of 30 o C over a period of 6 weeks. After 6 weeks of treatment, results showed that the predominant 3-ring PAHs, which made up 90% w/w, of the total PAHs concentration of 223.52 mg/kg, were degraded below detection and the 4-ring PAHs were reduced from 4 to 0.6% by the Pseudomonas while the Bacillus reduced the 3 and 4-ring PAHs respectively to 0.2 and 0.8%. This showed that the Pseudomonas degraded the 3 and 4-ring PAHs relatively better than the Bacillus. Both strains of bacteria degraded the 5 and 6-ring PAHs below detection limits. Furthermore, within the 3-ring PAHs each of the strains of bacteria reduced phenanthrene to approximately 0.2%, whereas both degraded the homologues acenaphthylene, acenaphthene and fluorene as well as anthracene below detection limits. For the 4-ring PAHs, the Pseudomonas degraded fluoranthene and benzo[a]anthracene while the Bacillus also degraded benzo[a]anthracene below detection limits. The Pseudomonas was able to reduce pyrene and chrysene to 0.3 and 0.2% respectively; whereas the Bacillus reduced fluoranthene, pyrene and chrysene to 0.1, 0.01 and 0.4% respectively. However, treatment with the mixed culture resulted in the limited degradation of the 5-ring PAHs particularly in the fourth week, which may be due to the phenomena of cometabolism and inhibition. The pseudo-first-order degradation rate constant of persistent PAHs ranged from 1.9 x 10 -4 to 9.3 x 10 -2 day -1 . Statistical analyses of results, using the 2factor analysis-of-variance, showed that the treatments applied resulted in significant (p < 0.05) differences in the biodegradation of the PAHs of the drill cuttings after the 6 weeks of treatment.

African Journal of …, 2008

The adsorption rate of chromium (VI) on commercial activated carbon during the treatment of the f... more The adsorption rate of chromium (VI) on commercial activated carbon during the treatment of the flocculation effluent of liquid-phase oil-based drill-cuttings has been investigated in terms of contact time and initial chromium (VI) ion concentration. Homogenizing 1 g of the activated carbon with 100 ml of the flocculation effluent of known initial concentrations (1.25 6.25 mg/l, in turn) in a flask, at a constant stirring speed of 80 rpm at 25 o C for 180 min, the pseudo-second-order kinetics was observed to be more suitable in predicting the adsorption rate of chromium (VI) ion in the treatment process as experimental data fitted the model relatively better than the pseudo-first-order kinetics with R 2 = 0.9999. Adsorption took place in two steps: an initial high rate step before reaching a plateau at equilibrium in the low rate step. Equilibrium was attained in a contact time of 60 min and the equilibrium adsorption capacity of the activated carbon was 78.6%. Equilibrium adsorption data fitted the Freundlich isotherm well with R 2 = 0.981. The intensity of adsorption was 1.32, which indicates a strongly favourable adsorption. This showed that a large proportion of the chromium (VI) ion was adsorbed at low concentration of the adsorbate in solution.

Recent Patents on Biotechnology, 2016

International Journal of Food Agriculture and Environment, 2007

... Auteur(s) / Author(s). AYOTAMUNO Josiah M. (1) ; KOGBARA Reginald B. (1) ; Affiliation(s) du ... more ... Auteur(s) / Author(s). AYOTAMUNO Josiah M. (1) ; KOGBARA Reginald B. (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). ... soils. ; surface water. ; Localisation / Location. INIST-CNRS,Cote INIST : 27691, 35400015997548.0560. Nº notice refdoc (ud4) : 18536124. ...

International Journal of Food Agriculture and Environment, 2006

Laboratory-scale studies were carried out using a nutrient formula produced from Eicchornia crass... more Laboratory-scale studies were carried out using a nutrient formula produced from Eicchornia crassipes plant to achieve bioremediation of crude oil impacted mangrove soil. In a 70 day study, the culturable heterotrophic bacterial population of the Eichhornia crassipes recipe increased from 6.26×10 5 Cfu/g to 2.69×10 7 Cfu/g. The control setup had its total culturable bacterial count increased from 5.76×10 5 Cfu/g to 1.24×10 6 Cfu/g. Statistical analyses showed significant difference for the two conditions (p ≥ 0.05). The total culturable heterotrophic fungal count in the Eichhornia crassipes recipe treatment increased from 5.36×10 5 Cfu/g to 2.50×10 7 Cfu/g respectively. The total culturable hydrocarbon utilising bacteria in Eichhornia crassipes treated polluted mangrove soil increased from 2.52×10 4 Cfu/g to 3.81×10 7 Cfu/g. Statistical analyses showed significant difference at p ≥ 0.05 level for the two conditions (Eicchornia crassipes nutrient treated soil and control). The total culturable hydrocarbon utilising fungal counts increased significantly for both the control and Eichhornia crassipes treatment. There was no regular trend in pH changes in all the conditions. The conductivity value of the Eichhornia crassipes recipe treated soil decreased progressively. Phosphate, nitrate, %total organic carbon, Total Hydrocarbon Content (THC). Studies using Gas chromatographic analyses showed that in the Eichhornia crassipes recipe treated polluted mangrove soil, 0, 58.92 and 75.36% were lost at zero hour, 28th day and 70th day respectively. In addition, in the control experimental setup , 0, 7.14 and 13.42% of TPH were lost at zero hour, 28th day and 70th day respectively. There was no significant difference between the control experiment and Eichhornia crassipes (p = 0.054). The use of organic nutrient sources such Eichhornia crassipes recipe/nutrient powder is of good use as source of limiting nutrient needed for bioremediation of crude oil impacted medium.

Mathematical analyses were used to develop model that predicts the influence of some hydraulic an... more Mathematical analyses were used to develop model that predicts the influence of some hydraulic and hydrologic parameters on the perennial flooding of some parts of the Calabar Metropolis. The parameters were obtained from ten sampling locations all within Calabar metropolis. An empirical model was developed to predict discharge based on the independent variables of cross sectional area of drains, degree imperviousness, gradient, sum of channel length, and basin area. The model developed gave a good multiple regression coefficient of 0.982 with a standard error of 0.709 at a significance level of 0.10. The R2 value of the regression model shows that 96.4% of the total variation in the storm water discharge is accounted for by the five regressors. Incorrect sizing and spread of drains as well as the existing slopes employed in the generation of the drains’ invert during construction have been seen as some of the key factors that foster flooding in the Metropolis. Designers are encoura...