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Sewage discharge is known to degrade the quality of receiving water bodies. This study assesses the impact of black water discharge on the physico-chemical parameters of River Zik in the University of Ibadan. Water samples were collected from five sampling sites along the stream located at progressive distances from the discharge point. Sampling was done three times over a period of three months (May to July 2012). The physico-chemical parameters tested were: pH, Biochemical Oxygen Demand (BOD 5 ), Dissolved Oxygen (DO), Electrical Conductivity (EC), Total Suspended Solids (TSS) and Nitrate. The overall mean values of the measured parameters were as follows: BOD 5 (381.1 mg/L); DO (3.9 mg/L); SS (1825.4 mg/L); pH (6.1); EC (618.5 μs/cm) and Nitrates (59.8 mg/L). The highest concentrations of BOD 5 , SS, EC and Nitrates were obtained at the point of sewage discharge into the stream. One-way ANOVA showed significant deviation from WHO standards for BOD 5 , SS, DO, EC and Nitrates (p < 0.05). This study showed that sewage discharge into River Zik have seriously contributed to the pollution of the stream to levels which pose health and environmental hazards to those using it downstream for domestic and agricultural purposes. This environmental hazards has been attributed to the little or near none existence of regulatory bodies responsible for regulating the strenght of black water discharge into sewers and/or recieving water bodies.

These A dewatering filter was designed and constructed to dewater sludge collected from Eleyele waterworks using slow sand filtration. Washed sand passing through sieve mesh size of 1.18 mm was used as the filter media. The flow rate of the filtrate was monitored for six (6) days and readings were taken at 30-minute intervals for 6 hours after each sludge loading of 15 L. The dewatered and dried sludge was investigated for use as brick material. The sludge and laterite samples were characterized using Atomic Absorption Spectroscopy. The major chemical components of  the sludge and laterite samples were silicon, aluminium and iron oxides. The laterite soil sample consisted of 60.47% SiO2, 17.77% Al2O3 and 8.18% Fe2O3 while the sludge sample consisted of 52.98% SiO2, 29.46% Al2O3 and 3.63% Fe2O3. Batching method by weight was used in mixing the materials in the ratios of sludge at 0%, 15% and 30% to produce laboratory scale bricks with dimensions of 70 mm by 70 mm by 70 mm and the properties of the bricks were investigated. The average compressive strength of the laterite bricks with dried sludge content of 0%, 15% and 30% were 3.15 N/mm2, 3.08 N/mm2 and 2.64 N/mm2, respectively. The results of this research demonstrated that a locally constructed sludge dewatering filter can be used to thicken waterworks sludge and laterite-sludge can be made from dewatered water works sludge.Keywords—Compressive strength, bricks, filter, media slow sand filtration, waterworks sludge

No abstract

Oil spill cleanup and subsequent restoration of the environment is majorly a function of spill cleanup methods applied. Some of these methods, though efficient, are, however, very expensive and require more personnel for their application and relative deployment in the field. The study was aimed at examining the efficiency of a locally and readily available, eco-friendly and low cost agricultural waste (coconut husk coir) as sorbent materials for spilled engine oil cleanup under static and dynamic marine water conditions. The sorbent material was prepared and used in three forms: raw coconut husk coir (CHC), modified coconut husk coir (MCHC), and reused coconut husk coir (RCHC). Under static and dynamic marine water conditions, oil sorption batch equilibrium experiments were used to study the engine oil sorption capacity and efficiency of the sorbent. Effects of sorbent dosage and sorption times on the oil sorption and efficiency of CHC, MCHC, and RCHC were studied and determined. At a constant sorption time of 60 minutes and varying sorbent dosages of 2-8 /320 ml of engine oil-marine water concentration, MCHC exhibited the highest oil sorption efficiency of 61.18% and 44.33% for dynamic and static conditions, CHC had 55.61% and 38.50% for dynamic and static conditions, whereas RCHC had 41.66% and 26.04% for dynamic and static conditions, respectively. It is statistically deduced from the results that sorption times and sorbent dosages have significant effects on the sorption efficiency of experimental coir for spilled engine oil removal. Though there is a need for proper blending or modifications of the sorbent material to enhance its affinity to oil and hydrophobicity, there are enough potentials in the materials for mild marine water current spilled engine oil cleanup.