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Dams are artificial lakes created to reserve water for a particular purpose. Reports on failure of dams are common things nowadays. Effects of dam's failure on man and environment are well known, which require preventive measures. This article presents a brief assessment of a dam in Nigeria and suggested necessary failure preventive measures. The dam site was visited (up and down streams), selected soil and geological properties of the dam were conducted with a particular attention to the release of water from the reservoir as seepage, or filling of the reservoir by silt from erosion. Hydrology and hydraulic data of the study area and spillway were obtained and analyzed. The study revealed that the soil is mainly sandy-loamy soil of averagely sand (73.99 ± 3.12), clay (8.53 ± 0.18), and silt (17.48 ± 1.88). Geological structure of the soil revealed that the study area is in basement complex. The reservoir capacity is 177,000,000 m 3 with about 18.5-m hydraulic high, silting rate of 0.301% per year. Hydraulic conductivity, transmissivity, and specific discharge were found to be of high side of 9.31 9 10 À4 m/s, 5.08 9 10 À4 m 2 /s, and 98.25 m/year, respectively. It was concluded that the current problems of the dam are high silting rate and seepage, big trees on the embankment and beside the spillway. All these may lead to failure of the dam in the following ways: lack of water in the reservoir due to seepage and silting, eutrophication and non-potable of the water due to silting and collapse of the embankment due to the presence of big trees. It was suggested that necessary and urgent solutions such as removal of trees from embankment, desilting and seepage control must be provided for safety of lives and properties. List of SymbolsQ Cumulative water available (m 3 ) Q r Water from rainfall (inlet, m 3 ) Q sp Seepage (outlet, m 3 ) Q ep Evaporation ? evapo-transpiration (outlet, m 3 ) Q wsp Water demand for water supply (220,000 people at 80 l/capita per day; m 3 ) Q ir Water demand for irrigation (at 7.00 mm of water per m 2 of land, m 3 ) Q sil Silting volume in the reservoir (outlet, m 3 ) APHA American Public Health Association A Cross-sectional area (m 2 ) = width 9 h C d Coefficient of discharge from the weir (0.5-0.95) g Acceleration due to gravity (9.81 m/s 2 ) Q flo Flow/discharge from the weir (m 3 /s) = 2.083 h Depth of the flow (m) C Runoff coefficient (0.25-1.0) I Rainfall intensity (mm/s) A w Catchment area (3,000 ha) R e Extraterrestrial radiation (J/m 2 /s), which depends on latitude and Julian day only T a Mean daily air temperature (°C), giving PE in units of m/s q wDensity of water (taken as 1,000 kg/m 3 ) kLatent heat flux (taken as 2.45 9 10 6 J/kg)

This paper is a report on an investigation conducted on adsorption of lead ions (Pb 2+ ) onto powdered corn cobs (PCC). Corn cobs were collected from a selected location in Nigeria. The corn cobs were crushed and pulverised into different particle sizes. Its compositions and adsorption properties of Pb 2+ onto PCC were studied. The effects of pH, particle size of PCC, and initial concentration of Pb 2+ on the adsorption properties were monitored. The adsorption capacities were analysed by using standard adsorption models. The models were evaluated statistically (total error, coefficient of determination (CD), model of selection criterion (MSC), and root mean square error). The study revealed that PCC contained 2.33%, 86.89%, 10.78%, 0.52%, and 4.56% ash, volatile, moisture, solubility in water, and solubility in 0.25 M of HCl by mass, respectively. Acid digestion of a gram of PCC indicated that PCC contained no chromium and lead, but contained 131 mg Fe, 54.79% carbon, 8.03% hydrogen, 0.41% nitrogen, 0.010 mg of Al, and 1.70 mg calcium. The isotherm models parameters were 28.509 L/mg and 0.141 mg/g; 0.138 mg/g and 11.494 L/mg; 0.142 L/mg and 0.013 mg/g; 0.129 mg/g and 25.641 L/mg, 28.509 L/mg, 3.795 mg/g and 2.336 for Langmuir, Freundlich, Temkin, activated sludge, and Redlich-Peterson. The PCC particle size, initial pH, and initial Pb 2+ concentration had effects on the adsorption parameters. The statistical evaluations showed that the best model for adsorption of lead ions from raw water onto PCC based on lower errors, high CD (0.88), reliability (97.5%), and MSC (1.86) was Freundlich and followed by activated sludge model. It was concluded that PCC is a good adsorbent like powdered eggshell and other carbon-based materials.

It has been estimated that about 80 percent of all the diseases in the developing countries are related to unsafe water supply and inadequate sanitation. Lack of access to improved sanitation and safe water [1] supply is a global crisis. The effects of inadequate water supply are more visible and prevalent in Sub-Saharan Africa. This paper presents an assessment of the existing water supply system at Wannune-Nigeria based on an onsite-physical inspection and discussion with some stakeholders. The assessment revealed that the existing water supply systems broke down due to poor and/or lack of proper operation and maintenance practice. This led to the dependence by residents on water from unprotected wells, rivers and streams. This is capable of causing some sanitation and water related diseases like cholera, diarrhea, among others. To improve the situation, a provisional design of a water supply system for Wannune was done. The system comprises a water treatment plant of 5,000 m 3 /d capacity, transmission mains of 41,000 metres length and three elevated reservoirs of 200, 500 and 1000 m 3 capacities for storage and transmission of the treated water.

Environmental pollution caused by the presence of toxic materials such as cadmium is becoming global problem and concern. This paper presents a report on kinetics of Cd 2+ removal from aqueous solutions through adsorption using powdered corn cobs (PCC). Corn cobs were collected from a selected location, washed to remove sand, air dried, ground and sieved into different particle sizes. The selected properties of PCC were determined using acid digestion method. Adsorption capacities through kinetics of Cd 2+ removal from synthetic solutions, typical raw water and domestic-institutional wastewater were studied. Effects of pH, PCC particle size, initial concentration of Cd 2+ and temperature on adsorption capacities were monitored through pseudo first-and second-order models, Elovich and intraparticle diffusion models to present adsorption rate parameters.The study revealed that PCC contained 86.89% volatile solids, had 4.56% acid solubility, 0.52 water solubility and 2.33% ash content. PCC removed Cd 2+ from aqueous solutions (synthetic, raw water, and wastewater). The relationship between time and concentration of Cd 2+ remaining in the solution followed exponential functions with squared correlation coefficient ranging from 0.9928 to 0.9993, 0.8701 to 0.9284, and 0.8514 to 0.9290 for synthetic solution, raw water, and typical domestic-institutional wastewater, respectively. Mechanism of cadmium adsorption onto PCC was in two separate stages linear portions in the first parts, while the final parts are curves indicating intraparticle diffusion. It was concluded that PCC is an effective adsorbent for Cd 2+ removal. The estimated production cost was 0.068 USD as against 0.50, 2.12, and 3.12 USD for producing adsorbents from empty fruit bunches; pencom shell and sugar cane based activated carbons, respectively.Cet article présente un rapport sur la cinétique du retrait du Cd2+ de solutions aqueuses par adsorption en utilisant de la rafle de maïs en poudre (RMP). Lesépis de maïs ontété collectésà partir d'un lieu sélectionné, lavés pouréliminer le sable, séchésà l'air, broyés et tamisés en particules de différentes tailles. Les propriétés sélectionnées de la RMP ontété déterminées en utilisant la méthode de la digestion acide. On aétudié les capacités d'adsorption par la cinétique du retrait du Cd2+ de solutions synthétiques, d'eaux brutes non traitées et d'eaux usées ménagères-institutionnelles. Les effets du pH, de la taille des particules de RMP, de la concentration initiale de Cd2+ et de la température sur les capacités d'adsorption ontété suivis par des modèles de pseudo-cinétique de premier ordre et de second ordre, Elovich et des modèles de diffusion intra-particule pour présenter des paramètres de taux d'adsorption. L'étude révèle que la RMP contenait 86,889% de solides volatils, avait une solubilité dans l'acide de 4,56%, une solubilité dans l'eau de 0,52 et une teneur en cendres de 2,331%. La RMP permettait de retirer le Cd2+ des solutions aqueuses (synthétiques, eau brute et eaux usées). La relation entre le...