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

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

Nigeria’s Legal Instruments for Land and Water Use: Implications for National Development

This chapter critically assesses the administration of land and water resources in Nigeria. Reasons why the Land Use Act has not met its objectives are discussed. It also assesses reasons why despite abundant water resources, numerous laws, and multiple governing institutions, Nigeria is still struggling to meet the national demand for water supply. The chapter concludes by suggesting specific amendments to the administration of both land and water resources. The main thrust of the suggested amendments is to address the current situation where government arrogates absolute authority on all land and water resources to itself. It is suggested that the government should consider adopting a multi-lateral relationship where government, private investors, traditional land owners, and prospective land buyers are co-decision makers in charting the future for the administration of land and water resources. This is aimed at eliminating associated problems such as delays, tenure insecurity and proliferation of peri-urbanization the current system

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