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Author: NWOSU, IFEANYI C.

Title: Characterization of Wastewater in Selected Urban Drains in Owerri, Imo State, Nigeria.

Affiliation: Civil Engineering Department
School of Engineering and Engineering Technology
Federal University of Technology, Owerri Imo State

Date: June, 2016

ABSTRACT
This study characterized wastewater constituents in selected urban drains of Owerri. The study also analyzed stormwater runoff and wastewater discharged from various drains in selected areas of the city of Owerri, Imo State. Quadratic regression and curve fitting modeling of the wastewater characteristics from the collection points (distances) was carried out. Comparison was also made with the effluent limitation guidelines given by National Environmental Standards and Regulation Enforcement (NESREA),WHO and other available  standards for wastewater disposal. Laboratory analysis of the samples included the following parameters: five-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), pH, Chlorides, Sulphates, Alkalinity and Total Hardness. The pH values obtained ranged from 6.0 – 8.2 with an average of 7.1.The sulphates ranged from 10.0 - 650 mg/l .The chloride was 20 - 650mg/l. The range of alkalinity values was 70 - 650mg/l. The range of total hardness was 90 - 620mg/l. The total solids ranged from 200 - 22000mg/l. The BOD5 ranged from 50 - 1200mg/l. The COD ranged from 80 - 1800mg/l. It was also noted that in most locations the TSS,COD and BOD5  were well above NESREA  limits while pH, sulphates and Chlorides were  within acceptable limits. Graphs of the various listed parameters against distance were plotted and the coefficients of correlation were determined. Characterization of wastewater is an important aspect of the design of the appropriate units of a wastewater treatment plant, besides result values obtained can further assist relevant authorities or interested individuals in planning, designing and managing an effective wastewater collection and treatment system so as to eliminate effects of environmental pollution and degradation in the region.

Author: NWAKWASI, NGOZI LIVINUS

Title: Modelling of Major Soil Nutrients Depletion in Crude Oil Contaminated Soil

Affiliation: Civil Engineering Department
School of Engineering and Engineering Technology
Federal University of Technology, Owerri Imo State

Date: June, 2016

ABSTRACT

 Modeling of major soil nutrients depletion in crude oil contaminated soil was carried out, using field experimental data generated from Research Farm Soil at the Federal University of Technology, Owerri, Imo State, Nigeria. The main objective of the study was to investigate the variation of nutrients, curde oil concentration and bacteria with time in the laboratory. To develop models for prediction of nutrient depletion with time and see how the models can be applied in field and bioremediation activities. The soil was artificially polluted with crude oil (bonny light) of different volumes/wt (i.e. 0.5, 1.0, 1.5, 2.0 and 2.5 litres per 10kg of soil), equivalent to 629 barrels/hectare, 1258 barrels/ha, 1887 barrels/ha, 2515 barrels/ha and 3144 barrels/ha respectively. Some physicochemical properties that reflects major soil nutrient content and fertility status (Nitrogen, Phosphorous, Potassium, Organic Carbon, Organic Matter and Soil pH) were determined, using standard methods. Results from the different levels of crude oil pollution over time showed that nitrogen content depleted from 0.287 to 0.123 within the first 14 days after pollution. Nitrogen content of the control sample was about three times higher than the values of nitrogen content at other various levels of crude oil pollution (0.021/0.0079) when averaged over a period of time (112 days). Similar results were obtained for phosphorous content which depleted five times over the control value when averaged over a period of time. Potassium content also showed a significant decrease from the control value, and was about 3 times lower when averaged over a period of time. There was, however, a slight increase in the organic carbon and organic matter content, which was about 1.5 times higher than the control value. The model values of major soil nutrients obtained from the various model equations were very close to experimental values. Hence the models are all suitable for determining the various contents of Nitrogen, Phosphorous, Potassium, Organic Matter and Organic Carbon in crude oil polluted site. The agitation/complaints over polluted farm lands in the Niger Delta region can now be resolved within the shortest possible time by utilizing the findings and model equations developed from the study. Hence, the cut-off between what really constitutes a poisonous dose and no-effect or tolerable dose in crude oil contamination can be determined using the models. 
 

Author: CHINEDU AFAM OKOYE

Title: Investigation of Compressive Strength of Stabilized Laterite-Sand Cubes

Affiliation: Civil Engineering Department
School of Engineering and Engineering Technology
Federal University of Technology, Owerri Imo State

Date: December, 2015

ABSTRACT
This thesis presents an investigation of compressive strength of stabilized lateritesand cubes. The study investigated the effect of two variables namely river sand and water-cement ratio on the compressive strength of laterite-sand cubes. The river sand content was between 0-20% by dry laterite weight and water-cement ratios of 1.2, 0.8 and 0.6 is adopted. Laterite soil classified as clayey sand using the USCS, having a moisture content of 12.69%, specific gravity of 2.67 and bulk density of 2445kg/m3 is used. Also, the river sand used is classified as poorly graded sand using the USCS, having a moisture content of 3.8%, specific gravity of 2.65 and bulk density of 1950kg/m3. A compactive effort of 5MPa is applied during moulding of the cubes having dimensions of 150mm. The cubes were cured by sprinkling water for 7 days under laboratory conditions and immersed in water for the remaining 21 days to ensure proper curing. Compressive strength test was carried out after a 28-day curing regime. The test recorded an average increase in strength of 23.09% between 1.2 and 0.8 water-cement ratio and 16.69% between 0.8 and 0.6 water-cement ratio. However, the relationship between the modified river sand content and the compressive strength was non-linear. An optimum river sand content of 20% recorded a compressive strength of 1.33N/mm2 for while an optimum river sand content of 14% river recorded a compressive strength of 1.87N/mm2 for 0.8 and 2.09N/mm2 for 0.6 water-cement ratios respectively. The linear regression model based method of ordinary least squares is used to generate equations that best describe the relationship between the compressive strength and the percentage river sand content. 
Keywords: Compressive Strength, River Sand Content, Water-cement ratio Compactive Effort, Linear Regression Model, Laterite-sand cubes. Method of Ordinary Least Squares.
 

Author: STANLEY EMEKA IWUOHA

Title: Buckling Analysis of Plates Subjected to Biaxial Forces Using Galerkin’s Method

Affiliation: Civil Engineering Department
School of Engineering and Engineering Technology
Federal University of Technology, Owerri Imo State

Date: September, 2016

ABSTRACT
This work studied the buckling analysis of plates subject to biaxial forces using the Galerkin’s method. Twelve boundary conditions were considered. The plate deflection equations were obtained using the polynomial series, and from the plate deflection equations, the expression for the critical buckling loads of the different plate boundary conditions were obtained for different aspect ratios, ∝ using the Galerkin’s functional. The aspect ratios, considered throughout this work, ranged from 1 to 2. A linear relationship was obtained between the buckling load on the y axis and those on the x-axis. Results of the critical buckling loads for the twelve cases were Obtained For The Various Aspect Ratios (1 To 2) And K (I.E. A Constant Which Relates Forces On The Y- axis with forces on the x-axis) values (0.1 to 1). The Critical buckling load results of a square simply supported plate at k equal to unity was obtained as 19.754. When compared with the value (19.744) obtained by Iyengar, Ventsel and Krauthermmer and Chajes, a percentage difference of 0.047 was obtained. At k equal to zero (i.e. for SSSS plates) and for different aspect ratios, the results of the present study showed a maximum percentage difference of 0.069 when compared with those given by Ibearugbulem et al. For other plate conditions such as those plates clamped on opposite edges and simply supported on opposite edges; two adjacent edges clamped and the other two simply supported; and those completely clamped, the critical buckling load values differed on the average by 0.1705%, 0.047%, and 0.650% respectively from those given by Ibearugbulem et al. at K equals zero. The highest buckling load coefficients were realized for a square plate that is fully clamped on all the edges. At k equals zero the value was 108.0006, while 12.3488 was the least buckling load coefficient, which was obtained for an all-round simply supported plate at k equals unity and an aspect ratio of 2. The plates with two opposite edges clamped, and the other two edges simply supported, the CSCS plates gave the highest biaxial buckling load coefficients for all k values at an aspect ratio of 1 (i.e. square plate), but, for other aspect ratios greater than 1 (i.e. rectangular plates) the SCSC plates gave higher results for all kvalues. From the results obtained and analyzed, it was therefore concluded that the orientation of the loads on the boundaries of the plates, affects its behavior. 

Author: CHIDIEBERE SAMPSON  EZENKWA

Title: Comparative Analysis of Rice Husk Ash and Saw Dust Ash on Tensile Strengths of Concrete

Affiliation: Civil Engineering Department
School of Engineering and Engineering Technology
Federal University of Technology, Owerri Imo State

Date: December, 2015

ABSTRACT
This study focuses on the comparative analysis of rice husk ash (RHA) and saw dust ash (SDA) on tensile strengths of concrete. RHA and SDA were obtained from open burning. The physical properties and chemical composition of the ashes were investigated. Ordinary Portland cement (OPC) was replaced with RHA, SDA, and RHA-SDA at 5%, 10%, and 15%. Concrete mix design was done using SCALE149 (Structural Calculations Ensemble) Software. Nine concrete cylinders of dimension 150×300mm with 100% OPC or 0% replacement with pozzolan were produced. Eighty one concrete cylinders were also produced for each of the percentage replacement of OPC with RHA, SDA, RHA-SDA, making a total of 252 concrete cylinders. The concrete cylinders were cured by immersion and tested for split tensile strength at 28, 90, and 150 days.  The results showed that RHA is a better pozzolana with combined (SiO2 + Al2O3 + Fe203) of  87.67%  compared to SDA which was 50.03% . The Split tensile strength decreased with increasing RHA, SDA, and RHA-SDA OPC percentage replacement. Laboratory values of 0.86N/mm2 and 0.78N/mm2 were obtained at 5% and 10% RHA-OPC replacement, 0.77N/mm2 and 0.58N/mm2 were obtained at 5% and 10% SDA-OPC replacement. Similarly, 0.82N/mm2 and 0.64N/mm2 were obtained at 5% and 10% RHA-SDA-OPC replacement. Split tensile strength of concrete with RHA, SDA, and RHA-SDA were lower at early age of curing but improved at later ages of curing. For example, at 5% RHA-OPC replacement, 1.42N/mm2 and 1.85N/mm2 were obtained at 90 and 150 days of curing.  At 5% SDA-OPC replacement, 1.28N/mm2 and 1.65N/mm2 were obtained at 90 and 150 days of curing. Similarly, at 5% RHA-SDA-OPC replacement, 1.35N/mm2 and 1.66N/mm2 were obtained at 90 and 150 days of curing, as against 1.34N/mm2 and1.61N/mm2  attained by the control at 90 and 150 days of curing. Models were developed to predict the tensile strengths of concrete containing RHA and SDA as binary and ternary blend with OPC at varying percentage replacements and curing ages. The models were tested and found to be adequate.