Pollution Studies on Ground Water Contamination: Water Quality of Abeokuta, Ogun State, South West Nigeria

Changes in water levels in wells reflect changes in recharge to, and discharge from an aquifer. Generally groundwater is rain water or water from surface water bodies, like rivers, lakes or streams that permeate into the soil and bedrock and is stored underground in the pores spaces between soil particles. Groundwater pollution occurs when hazardous substances come into contact and dissolve in the water in the soil or on the surface. Groundwater is generally less susceptible to contamination and pollution when compared to surface water, naturally impurities in rainwater or surface water which replenishes groundwater systems, get removed while infiltrating through soil strata. In Nigeria, groundwater is used intensively for irrigation and domestic purposes, a variety of land and water-based human activities are causing pollution of this precious resource. Its over-exploitation is causing aquifer contamination in certain instances, while in certain others its unscientific development with insufficient knowledge of groundwater flow dynamic and geo-hydro-chemical processes has led to its mineralization. Adequate supply of safe and portable fresh water is an inevitable factor for socio economic development.  Although the recent global attention focuses on how the current and foreseeable water crisis and associated consequences would be addressed, quite a lot of factors such as  low level of education, insufficient budgetary funding, inefficient government policies,  drought are increasingly contributing to the pollution of domestic water in Nigeria. Keywords: Nigeria, Groundwater, Pollution, soil strata, Qualit

GROUNDWATER QUALITY ASSESSMENT USING WATER QUALITY INDEX IN SOME PARTS OF ODEDA, SOUTH-WESTERN NIGERIA

Groundwater quality samples were collected from boreholes and hand-dug wells located in some parts of the study area and were assessed for some physico-chemical parameters including pH, Electrical Conductivity, Total Dissolved Solids, total hardness, chloride, sulphate, nitrate, calcium hardness, magnesium hardness, potassium, iron and alkalinity. The results showed that most of the water quality parameters fell below the WHO maximum permissible limits with a few exceptions in about three locations. The quality indices were determined for each location and the values were found to be 20.86 – 57.40 indicating that about 75% of representative samples of the locations were good while about 15% was classified as poor. This can be attributed to high concentration of nitrates, EC, sulphates and total hardness in a few sample locations. The general low water quality index may have resulted from better sanitary conditions and improved living standards as well as the fact that the study was conducted at the peak of the rainy season. This type of assessment could be used as a powerful tool for making decisions and implementing water related policies as it documents water quality results that is easily understood by stake holders

Laboratory scale bioremediation of crude oil impacted soil using animal waste compost

This study investigated various ways by which the rate of biodegradation of hydrocarbons {ex-situ treatment} can be enhanced in an efficient, cost effective and environmentally friendly manner. To achieve this, bioremediation processes were applied to a crude oil impacted soil. Tests were conducted to evaluate the biodegradation effect of the oil on the soil e.g. effect on density, electrical conductivity, etc. The percentage of organic matter and carbon was evaluated in order to determine the organic carbon interaction with the contaminated soil sample. The effect of contamination on the geotechnical properties of the contaminated soil was also evaluated using compaction test. Two types of compost - sheep waste compost and crude oil (SCRO), and goat waste compost and crude oil (GCRO) - with an application rate of {0g, 350g and 550g} were applied in the treatment. The results showed that all bioremediation agents applied enhanced the natural bioremediation of the contaminated soil and the most preferred results were obtained when treatments were done using SCRO compost. This study revealed that the remediation process was influenced by application period, type of oil, and compost rate

SEDIMENT QUALITY ASSESSMENT OF OKE-ITOKU RIVER, ABEOKUTA, SOUTHWEST NIGERIA

This research investigated contamination of sediments due to continuous tie and dye effluents discharge into Oke-Itoku River, Abeokuta, Nigeria. Surface and subsurface sediment samples were collected upstream, at point of discharge and downstream. The contamination factor (Cf), degree of contamination (Cd) and geo-accumulation index (Igeo) were also determined. Physico-chemical parameters such as Temperature, Total Dissolve Solids (TDS), Electrical Conductivity (EC), pH, Dissolved Oxygen (DO) and five selected heavy metals: Chromium (Cr), Copper (Cu), Cobalt (Co) and Lead (Pb) were measured. Results revealed mean TDS, EC, Temperature and DO pollution of 485.6±134.66 mg/L, 2153.6±1122.19 µS/cm, 32.46±0.570C and 4.01±0.43 mg/L respectively at the discharge point. The heavy metal concentrations for the surface and subsurface sediments obtained had a range of 11.5-18.3, 30.1-39 mg/L for Cr; 12.6-27.0, 23.8-42 mg/L for Cu; 16.2-31.0, 23.8-42.0 for Co and 1.8-3.2, 1.8-3.5 mg/L for Pb in surface and subsurface sediment respectively. Heavy metal contamination in the sediments of Oke-Itoku river showed order of enrichment of Co>Cu>Cr>Pb according to Cf, Cd and Igeo for the study area. There are only natural inputs of chromium and copper into the river while Cd, Co and Pb concentrations are due to anthropogenic input mainly from tie and dye by-products

Characterisation of activated charcoal, sawdust charcoal and rice husk charcoal as adsorbents in water treatment

This study is an investigation into the characterization of commercial activated charcoal, sawdust charcoal and rice husk charcoal as adsorbents for water treatment. The ground rice husk and waste sawdust collected, were sieved to obtain a nominal size of 1mm, washed and oven-dried for 12hours. The two materials were pyrolysized in a furnace for 30minutes, and the chars produced were later air-dried. The three charcoals (sawdust charcoal, rice husk charcoal, and the activated charcoal purchased from the market) were all subjected to X-ray Fluorescence (XRF) analysis, Scanning Electron Microscope (SEM) analysis and Energy Dispersive X-ray (EDX) analysis in order to characterize the filter materials. The SEM analysis showed that the three materials developed more pores, which is a property of an adsorbent. Likewise, the XRF and EDX analyses confirm that all the three adsorbents possess larger proportion of Silica, Carbon and Oxygen

EVALUATION OF TWO-STAGE SUBSURFACE FLOW CONSTRUCTED WETLANDS FOR ABATTOIR WASTEWATER MANAGEMENT

Abattoir wastewater is high in organic content, the waste recovery and treatment facility is expensive and this results in indiscriminate dumping into streams without adequate treatment. The effectiveness of using a two-stage subsurface flow constructed wetland to treat abattoir effluent was examined in this study. Diluted abattoir wastewater from Lafenwa Abattoir, Abeokuta, Ogun State, Nigeria was fed into a two-stage Vegetated Subsurface Bed Constructed Wetlands (VSBCW). The VSBCW consisted of 500 mm deep 10-15 mm diameter granite with 150 mm thick overlay of well graded sand planted with locally available Vetiveria nigritana. Grab samples were collected at selected points along Ogun river and measurement of physico-chemical parameters such as: Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Electrical Conductivity (EC), Total Dissolved Solids (TDS) and Total Suspended Solid (TSS) of the influent and effluent from the VSBCW were carried out. Irrigation with water and diluted abattoir wastewater to examine the variation in plant growth rate was also investigated. The results revealed a pollution load reduction as the wastewater moves away from the discharge point but inadequate to meet the FEPA (1991) standard for wastewater discharge into rivers. The VSBCW was observed to reduce the concentration of BOD5, COD, EC, TDS and TSS in the abattoir wastewater by 88.71, 87.28, 45.72, 56.89 and 72.27 % respectively. The growth rate of the V. nigritana reduced by 1.9% when irrigated with abattoir wastewater. The study revealed that locally available V. nigritana in VSBCW is effective in abattoir wastewater treatment and could be use to curtail the pollution caused by discharge of untreated wastewater into rivers.     &nbsp

Analysis of auto-purification response of the Apies River, Gauteng, South Africa, to treated wastewater effluent

The assimilative capacity of water bodies is an important factor in the integrated management of  surface water resources. The current study examined the auto-recovery processes of the Apies River from wastewater discharged into it from a municipal wastewater treatment facility, using a series of equations, including the modified Streeter-Phelps equation. Field data obtained include dissolved oxygen (DO), temperature, stream velocity, depth, and width. Water samples were also obtained at 10 sampling stations for the determination of biochemical oxygen demand (BOD) using standard methods. It was observed that the DO and BOD level (5.59 mg/L and 8.5 mg/L respectively) of the effluent from the wastewater treatment facility indicated better water quality than the Apies River background DO level (5.42 mg/L) and BOD level (13 mg/L). Also, at 270 m downstream of the effluent discharge point, another effluent stream (Skinnerspruit) adversely impacted on the Apies River with DO and BOD levels of 6.5 mg/L and 9.0 mg/L, respectively, compared to the Apies River background values of 6.81 mg/L and 8.0 mg/L, respectively. The stream, however, recovered well from both the background and imposed pollution sources as it had a computed positive auto-recovery factor of 1.74. Furthermore, the measured DO deficit was plotted against predicted DO deficit. The plot revealed a close match between the measured and predicted DO deficit, indicating that the model could be used for predicting DO deficit along other segments of the river. To further improve on the natural  auto-recovery processes of the Apies River, it was recommended that flow along the Skinnerspruit should be enhanced by clearing the observed aquatic plants growing within the channel. Also,  suspected pollution activities taking place further upstream on the Apies River should be investigated and appropriately addressed.Keywords: de-oxygenation; re-aeration; auto-purification; dissolved oxygen; biochemical oxygen  demand; strea

MECHANICAL PROPERTIES OF THREE SELECTED TIMBER SPECIES IN ABEOKUTA, OGUN STATE, NIGERIA

This study was conducted to determine the physical and mechanical properties of some common Nigerian timber species in Abeokuta, southwest Nigeria.. The timber species considered are: Ayinre (Albizia coriaria), Aga (Musanga cecropioides) and Orin dudu (Anogeissus leiocarpus). The physical properties of the selected timber species including moisture content and density were determined in accordance with timber design codes {EN 13183-1 and EN 408}. Mechanical properties of the timber species were determined using both four and three point bending tests based on standards such as EN 408 and ASTM D193. Characteristic values of the material properties were determined in accordance with EN 384. Mechanical properties and density of the selected timber species were modified to the equivalent moisture content of 18% in accordance to the standard code for Timber design in Nigeria (NCP). The least values of the mechanical properties obtained from the two standards mentioned above were considered

Characterisation of activated charcoal, sawdust charcoal and rice husk charcoal as adsorbents in water treatment

This study is an investigation into the characterization of commercial activated charcoal, sawdust charcoal and rice husk charcoal as adsorbents for water treatment. The ground rice husk and waste sawdust collected, were sieved to obtain a nominal size of 1mm, washed and oven-dried for 12hours. The two materials were pyrolysized in a furnace for 30minutes, and the chars produced were later air-dried. The three charcoals (sawdust charcoal, rice husk charcoal, and the activated charcoal purchased from the market) were all subjected to X-ray Fluorescence (XRF) analysis, Scanning Electron Microscope (SEM) analysis and Energy Dispersive X-ray (EDX) analysis in order to characterize the filter materials. The SEM analysis showed that the three materials developed more pores, which is a property of an adsorbent. Likewise, the XRF and EDX analyses confirm that all the three adsorbents possess larger proportion of Silica, Carbon and Oxygen

Estimation of Water Requirements of Selected Field Crops in South- West and South- East Nigeria

Estimation of crop water requirement of some selected field crops was carried out based on twenty-one years and ten years meteorological data at Abeokuta and Umudike respectively. These crops include as maize, pepper and tomato. Reference evapotranspiration was calculated using BlaneyCriddle model for Abeokuta and Penman Model for Umudike. The result obtained showed that the seasonal crop evapotranspiration (ETcrop) for maize, pepper and tomato were 378.33, 558.51 and 505.92mm/month in Abeokuta and 353.13, 130.97, and 464.82mm/month in Umudike. Effective rainfall (ER) was lower than the water requirement in the months of May and June for maize cultivation in Abeokuta, similarly, effective rainfall was lower that the water requirement in the months of March, April, May and August for pepper in Abeokuta. This indicates that supplemental irrigation was needed during these months. Irrigation water requirement (IR) was 11.73mm for soils of Umudike. The study also established that pepper and maize could be grown conveniently during their growing season without supplemental irrigation in Umudike. However, the sufficient water availability for crops in Umudike during their growing season will produce good yields and good quality crops compared to Abeokuta