262 research outputs found
Composite Goodness of Fit in Reaeration Coeffcient Modeling
Determination of reaeration coefficient is an important factor in surface water quality modeling as it determines
the efficiency of the Streeter-Phelps model used for predicting dissolved oxygen deficit of any stream. This study
compared the efficiency of Atuwara model with ten other reaeration coefficients models by making use of three
data sets obtained from river Atuwara during the prevalent wet and dry seasons using composite goodness of fit
test which was developed by quantitatively combining statistical and graphical goodness of fit. The eleven tested
models were ranked in order of performance. Results show that the four top ranking models were developed
through a process that utilized data from multiple streams while models that were developed from data obtained
from the test subject alone performed less competitively. The outcome of the study also suggests that the usual
practice of selecting the best model based on statistical analysis alone does not necessarily yield the best result
and therefore recommended the incorporation of quantitatively analyzed graphs. The paper concludes that
selection of the best performing model among existing reaeration coefficient models using the composite
goodness of fit may present a cheaper and better alternative to conventional model development approach
Sustainable groundwater exploitation in Nigeria
In this study, a critical review of the groundwater resources history and management in Nigeria was done. The
aim was to identify reasons why groundwater is increasingly being exploited in recent times, and to explore ways through
which the exploitation could be done sustainably. This was achieved through literature review. It was observed that an
estimated 60% of Nigeria’s population get drinking water from ground resources. This high statistic is mostly the resultant
effect of infrastructural decay in the potable water supply sector of the country. In Nigeria, just 14 % of the country’s
population get regular water supply through piped sources while the remainder of the country’s 162.5 million people draw
their water supply mainly from surface and groundwater sources. Groundwater, in Nigeria, is accessed mainly in form of
shallow (hand-dug) and deep (boreholes) wells. Well water withdrawal activities are mostly un-regulated and, therefore, the
water sources are often subjected to avoidable abuses and pollutions. In particular, rapid urbanization, agricultural and
industrial activities are major contributors of pollutions to groundwater sources. Also, unavailability of data such as
geographical information on water quantity, hydrology, state of aquifer and withdrawal limits have contributed to the
unsustainable use of groundwater in Nigeria. It was recommended that proper regulation of groundwater resources and its
protection under the land use act of 1978 could be instrumental to its sustainable exploitatio
WASTE MANAGEMENT AND WATER QUALITY ISSUES IN COASTAL STATES OF NIGERIA: THE OGUN STATE EXPERIENCE
Waste dumping and inadequate waste management efforts are having adverse impact on the environment and humans in
Nigerian coastal cities. Nine of the 36 states in Nigeria border the Atlantic Ocean. Twenty-five percent of the Nigerian
population is found in the coastal states. These states, with the exception of Lagos, Ogun and Ondo, are more prone to
petrochemical wastes arising from petroleum exploration. Field investigations, surveys and literature searches were
conducted in order to accomplish the task of this research. Field studies included testing for dissolved oxygen, biological
oxygen demand, nitrates, phosphate, total solids and pH
Cadmium And Lead Contents Of Unpackaged Tapioca Exposed For Sale In Selected Markets In Lagos, South West Nigeria
The levels of cadmium and lead in unpackaged Tapioca, a cassava product, consumed as breakfast meal from five selected markets were investigated using the anodic stripping voltammetry. The levels of cadmium in tapioca ranged from 1.7 to 2.7ug/g, while the lead contents ranged from 5.2 to 7.6ug/g. Analysis of the results using the t- test shows that the lead level in tapioca samples from Agege, Orile Agege and Oyingbo did not differ significantly (p≤0.05) from each other. However, they differed significantly from those samples from Oke-Odo and Mushin. The cadmium levels in Tapioca samples from Agege, Mushin and Oke-Odo differed significantly (p≤0.05) from the samples of tapioca from Orile Agege and Oyingbo. The level of the contaminants did not exceed the level found in human milk in studies carried out by World Health Organization in selected countries. The results provide reliable information on the possible dangers arising from the consumption of unpackaged tapioca exposed to contaminants on high traffic motorways.  
Reaeration Coefficient Modelling: Case study of River Atuwara, Ota, Nigeria
This study was carried out on River Atuwara in Ota, Ogun State, Nigeria with the aim of developing a coefficient of re-aeration model applicable to River Atuwara and other rivers in the Nigerian environment. This was achieved by sourcing for data once every month from 22 sampling locations of interest within a pre-selected segment of the river over a period covering the dry and wet seasons. The data collected include hydraulic data (depth, width, velocity and time of travel) and water quality data such as Dissolved Oxygen (DO) and Biochemical Oxygen Demand (BOD). Excel Spreadsheet and MATLAB were used for data processing. Regression analysis was carried out where stream velocity and depth were the regressors and the re-aeration constant k2 (as a function of BOD, DO and Temperature) was the dependent variable.
A coefficient of re-aeration, k2, (Atuwara re-aeration model) was developed and validated statistically. Its performance was also verified by comparing the model with 10 other internationally recognized models. It was found that even though Atuwara model performed better than Agunwamba model and most of the other well cited models, both Atuwara model and Agunwamba model could be safely adopted for future water quality modelling researches in the Nigerian environment. Results of detailed water analysis of samples from River Atuwara shows high level of pollution hence it is unfit for human consumption without adequate treatment. It is recommended that River Atuwara and similar rivers in the country should be regularly monitored for quality control
Water Quality Modelling: Case study of the Impact of Abattoir Effluent on River Illo, Ota, Nigeria
This report presents results obtained from the investigation and water sampling exercise carried out on the segment of River Illo that passes through Sango in Ado Odo-Ota Local Government Area, Ogun State, Nigeria. The report reveals that while some people used water from the river for domestic, food production and recreation purposes, others discharge their wastes without any form of pre-treatment into it. The multipurpose usage of water from River Illo by local residents thus hinges public health on the self-purification capacity of the river alone.
Information on water use and waste disposal practices of the local residents were obtained through direct observation and oral interview of members of randomly chosen households built along the river within a distance of 2km. Single grab samples of water were obtained from the river at the site of an abattoir effluent discharge at distances 0m, 10m, 20m, 30m, 50m and 100m from the point of discharge. A seventh sample was also obtained 10m upstream of the point of effluent discharge to furnish information on ambient conditions of the river prior to pollution while an eighth sample which was prepared by diluting the water obtained at 0m with distilled water (i.e. 25% stream water, 75% distilled water) was included to serve as control sample. All water samples were transported (within 3 hours of isolating them from the river body) to the laboratory for analysis and the results were subjected to graphical, statistical and mathematical analysis.
Pollution from the abattoir caused a drop in dissolved oxygen level of the river from an ambient value of 4.6mg/l to 0.01mg/l at the point of discharge. The pollution also caused an increase of 447.5mg/l to 1071.5mg/l in T.S., 0.04mg/l to 4.4mg/l in ammonia, 170mg/l to 670mg/l in BOD, 0.05mg/l to 3.05mg/l in phosphorus, 50mg/l to 1066.7mg/l in alkalinity and 18mg/l to 820mg/l in Acidity. It was also found out that between 30m – 80m downstream of the pollution point, a threat of eutrophication is caused by plants growing in the river path. Despite this obstruction, the river recovered considerably to a D.O. level of 3.9mg/l at 100m downstream. Results from the dispersion modeling shows the self-purification capacity of the river, f, to be 1.1 within 30m distance from the point of discharge and 0.8 between 30m and 100m from the point of discharge. The results from the application of the Streeter-Phelps model showed that the eutrophication occurring between 30m – 80m is interfering adversely with the self-purification processes of the river. The percentage compliance of each of the eight water samples with Guideline Values (GLV) of WHO and FEPA was performed. None of the samples met the minimum requirements for BOD, COD and TSS, which are indicators of pollution.
It was concluded that River Illo is being polluted by abattoir effluents discharge thereby exposing the health of local residents who use the water from the river for domestic, recreation and food production purposes to avoidable risks. Suggested actions that could further complement the self-purification capacity of the river were offered
EVALUATION OF WATER QUALITY MODELLING PARAMETERS: TOWARDS THE EVOLVEMENT OF RE-AERATION COEFFICIENT FOR RIVERS IN THE NIGERIAN ENVIRONMENT
This study was carried out on River Atuwara in Ota, Ogun State, Nigeria with the aim
of developing a coefficient of re-aeration model applicable to River Atuwara and
other rivers in the Nigerian environment. This was achieved by sourcing for data once
every month from 22 sampling locations of interest within a pre-selected segment of
the river over a period covering the dry and wet seasons. The data collected include
hydraulic data (depth, width, velocity and time of travel) and water quality data such
as Dissolved Oxygen (DO) and Biochemical Oxygen Demand (BOD). Excel
Spreadsheet and MATLAB were used for data processing. Regression analysis was
carried out where stream velocity and depth were the regressors and the re-aeration
constant k2 (as a function of BOD, DO and Temperature) was the dependent variable.
A coefficient of re-aeration, k2, (Atuwara re-aeration model) was developed and
validated statistically. Its performance was also verified by comparing the model with
10 other internationally recognized models. It was found that even though Atuwara
model performed better than Agunwamba model and most of the other well cited
models, both Atuwara model and Agunwamba model could be safely adopted for
future water quality modelling researches in the Nigerian environment.
Results of detailed water analysis of samples from River Atuwara shows high level of
pollution hence it is unfit for human consumption without adequate treatment. It is
recommended that River Atuwara and similar rivers in the country should be regularly
monitored for quality contro
Wind Energy Study and Energy Cost of Wind Electricity Generation in Nigeria: Past and Recent Results and a Case Study for South West Nigeria
The study assessed the wind energy potential of ten selected sites in the south western region of Nigeria and carried out a cost benefit analysis of wind power generation at those sites. Twenty four years’ (1987 to 2010) wind speed data at 10 m height obtained from the Nigerian meteorological agency were employed to classify the sites wind profiles for electricity generation. The energy cost analysis of generating wind electricity from the sites was also carried out. The outcome showed that sites in Lagos and Oyo States were adequately suited for large scale generation with average wind speeds ranged between 2.9 and 5.8 m/s. Those from other sites may be suitable for small scale generation or as wind farms, with several small turbines connected together, to generate large enough wind power. The turbine matching results shows that turbines cut-in and rated wind speeds of between 2.0 and 3.0 m/s, and between 10 and 12.0 m/s respectively will be very suited to all the sites, particularly those in locations outside Lagos and Oyo States. The energy cost analysis shows that generation cost can be as low as 0.02 €/kWh and as high as 5.03/kWh, depending on the turbine model employed
Study of Auto Purification Capacity of River Atuwara in Nigeria
The aim of this paper was to study and predict the self-purification capacity of River Atuwara. This was done primarily by measuring the Dissolved Oxygen (DO) downstream of a pre-selected pollution discharge point on River Atuwara and then predicting the same using the modified Streeter-Phelps equations. Other data gathered from each of the 17 sampling stations on River Atuwara and used in the analysis included Biochemical Oxygen Demand, (BOD), pH, stream velocity, stream depth and distance. Predicted DO deficit trend lines were first fitted by retaining the original re-aeration coefficient component, k2, of the modified Streeter-Phelps equation (USGS equation) and subsequently by substituting it with Atuwara reaeration coefficient model. It was found that the latter displayed better predictive capacity. Results also demonstrated that the auto-purification capacity of the river which is already limited by the relatively low DO saturation level is further threatened by the wastes being discharged into it at varying intervals. Some of the wastes which are non-biodegradable and acidic were also found to be interrupting the auto-purification processes of the river. Water from River Atuwara requires treatment before it can be considered safe for consumption by its current users
WATER RESOURCES USE, ABUSE AND REGULATIONS IN NIGERIA
The evolvement processes of water laws in Nigeria, as well as their efficiency in the sustenance of
surface water resources, were studied. A cursory look was also taken into the mode of access to
water resources by households in Nigeria. This was done vis-Ã -vis the governmental effort at
providing potable water for its teeming population as well as the Land Use Act of 1978, which vests
absolute control and ownership of all water resources, ground and surface, in the land owner. About
47 million Nigerians still rely, exclusively, on surface water sources to meet their domestic needs.
Yet, pollution discharge into the surface water by individuals and industries go on unmitigated,
unregulated, and unpunished due to weaknesses in the existing laws. The involvement of the
scientific community in the regular calibration and monitoring of surface water quality as a tool for
managing the surface and groundwater resources, among other things, would be an advantageous
tool for curbing the pollution menace
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