A COMPARATIVE STUDY OF Moringa oleifera AND ALUMINUM HYDROXIDE CHLORIDE IN GREYWATER TREATMENT IN ABEOKUTA, OGUN STATE, NIGERIA.

Two methods of treating water using a natural coagulant and a chemical coagulant were assessed. The natural coagulant was Moringa oleifera seeds (a forest plant) i.e Treatment ‘A’ while the chemical used was Aluminum hydroxide chloride i.e Treatment ‘B’. The aim of this study was to compare the use of a natural coagulant with a chemical coagulant.  Samples were collected at Omida,  Ibara, Mama Cass, Mr Bigg’s and Sidipon village respectively. The filtrate of   Moringa oleifera seed extract was dosed into the greywater sample at 10% dosing range and made to run through a greywater treatment plant while Aluminum Hydroxide Chloride was also dosed at 10% dosing range and made to run through the treatment plant respectively. The greywater treatment plant   is a self designed treatment plant made to treat both water and wastewater. The raw water was firstly analyzed, after which the treated samples were taken to the laboratory for analysis.  Result for the physical, chemical and bacteriological analysis of treatment ‘A’ before and after treatment were as follows: pH (9.3, 9.7), EC (2995, 1175μs), Temperature (27.7, 27.6oc) , TDS (365, 155ppm),  TSS (0.32, 0.30ppm), TS (376, 155ppm), Sulphate (588, 314mg/l), Magnesium (400, 260mg/l), Nitrate (7.5, 6.1mg/l), Phosphate (285, 12mg/l) and total coliform count after treatment is given as (2.8x103 cfu/ml), while that of treatment ‘B’ before and after treatment were as follows: pH(11, 9.9), EC (3000,630), Temperature (27.7, 27.6oc), TDS (0.47, 0.45ppm), TS (416, 320ppm), Sulphate (571, 246mg/l), Magnesium (820,  860mg/l), Nitrate (4.4, 6.0mg/l), Phosphate(169, 6.1mg/l)  the  total coliform count after treatment was  given as ; (3.0x103cfu/ml). One-way Anova test was used to determine differences between results obtained using the two coagulants. The result indicated no significant difference at p=0.05 between the two treatments. Hence, result was further compared with World Health Organization Standard for Drinking Water.  Comparatively, the analysis obtained from water treated with Moringa oleifera was found to be more effective than the chemical coagulant, and can be easily made available for the use of the populace.   &nbsp

EFFECT OF UNTREATED SEWAGE DUMP ON THE QUALITY OF GROUNDWATER IN IDDO COMMUNITY, LAGOS, NIGERIA

This study was carried out to assess contamination of groundwater in Iddo as a result of many yearsof untreated sewage dump into the adjacent Lagos lagoon. Water samples were collected from fivedifferent sites in the lagoon at certain intervals. Similarly, water samples were collected from five boreholesand seven hand – dug wells sited in the immediate neighbourhood of the sewage dump sites.Sampling covered both the dry and wet seasons and tested for faecal coliform (FC) counts along withother parameters such as Biochemical Oxygen Demand (BOD) and salinity in order to determine theireffects on the density of faecal coliforms. Analysis of parameters was subjected to standard proceduresand data presented in simple statistics. Results for faecal coliform in boreholes ranged from 20-100 total plate count (TPC) /ml in dry season and 5-100 TPC/ml in wet season, while in well water, thevalues are >100 TPC/ml (dry season) and 30 TPC/ml – TNTC (too numerous to count) (wet season).In the lagoon water samples, faecal coliform counts are generally greater than 100 TPC/ml in dry seasonand varied between 100 TPC/ml and TNTC in wet season. BOD values of the lagoon varied fromND (not detected) to 2.8 mg/l (dry season) and 2.4-3.8 mg/l (wet season) with salinity values 3.27-3.45% and 0.70-0.96 % in dry and wet season respectively. Coliform values were higher than World HealthOrganisation standard in drinking water. Results of analysis showed that both surface water andgroundwater in Iddo community are heavily contaminated by the disposal of untreated sewage dump

TOWARDS EFFECTIVE PLANNING, DESIGN AND MONITORING OF DAMS IN NIGERIA

Besides serving as a center of tourist attraction, creating jobs for the unemployed, a rich source of fish and a fallback in times of drought, a dam also creates electricity from nothing other than the falling of water through its turbines. In Nigeria, like in many other parts of the world, dam projects are often seen as key to economic solution through hydroelectric power supply. The technology of dam construction in Nigeria is still experimental. There are so many unknown factors in dam design, construction and operation that may affect dam’s safety and performance. Relying on field experience from various parts of Nigeria, this paper examines the essential details necessary for consideration in dam planning and design using the complete and accurate information on the important variables such as technical, environmental, socio-cultural, economic or cultural factors. The results of these examined factors indicated that most of dam projects in Nigeria are not properly planned. The basic planning flaws include hydrologic, environmental and social factors which are seen by dam builders as obstacles to be ignored, covered up or surrogated to engineering in the project planning. Incorrect calculation of flood flows has lead to dam failures and reservoir siltation has drastically reduced the lifespan of dams, making one to conclude that the entire concept of dam safety as a design criterion is a new one. It appears that Nigeria will have to live with these flaws and some of these cost for sometimes to come. There is, therefore, the need for us to reduce these through proper planning, design and monitoring of our dams. It is recommended that a comprehensive dam safety study of all old dams (i.e. ≥ 20 years) be carried out. &nbsp

HUMAN HEALTH AND ENVIRONMENTAL RISK ASSESSMENT OF THE ALAKIA INDUSTRIAL DISTRICT OF IBADAN, SOUTH WEST NIGERIA

A scientific survey was conducted in February 2002 in three communities (Majawe, Osun-Abolowojaiye and Papa Adogba) communities of Alakia Industrial district of Ibadan to determine the extent of the damages caused by the negative impact of the industrial effluent discharges into the Elesin stream and emissions of gaseous pollutants into the atmosphere within the three communities. A socio-economic survey was also carried out to establish the impact(s) on human and livestock populations of the study area. A sample of non-affected areas served as control for comparison. The degree of pollution was established by the determination of the concentrations of the metals including Pb, Ca, N, K, Cd, Fe, Zn, Ca, Cr, Mn, Na, Mg, a specific non metal phosphorus as well as chlorides (Cl-) and Nitrates (N03-). The study established the presence of metals in concentrations higher than the recommended limits in effluent discharges in all the samples in the study area and a clear link between the effluent discharges and pollution with its severe damages in the area

QUALITATIVE AND QUANTITATIVE ASSESSMENT OF RAINWATER HARVESTING FROM ROOFTOP CATCHMENTS: CASE STUDY OF OKE-LANTORO COMMUNITY IN ABEOKUTA, SOUTHWEST NIGERIA

Quantitative and qualitative assessment of Rainwater harvesting system from rooftop runoff from acatchment at Oke-Lantoro Community in Abeokuta, Southwest Nigeria was determined using eightroof designs in respect to slope and six selected roofing sheet materials respectively. The resultshowed that the steeper the roof slope the more the rainwater harvested irrespective of rainfall amountand duration. The roof pattern with a large and steep slope designed with gutter tends to harvest morewater and at a higher rate. Physico-chemical analysis of the harvested water samples gave resultswhich varied from various drinking water quality regulatory standards. Sample from galvanized roofingsheet was influenced by zinc and lead in quantity beyond human consumption level, while the asbestosroofing sheet water sample gave higher calcium and magnesium contents which reflected in thetotal hardness value. Sample from the aluminum roofing sheet gave the best result but it was alsoaffected by the influence of atmospheric dust particles and faecal materials of birds, lizards and othersmall organisms. Considering the results of the physico-chemical tests, the harvested water samplescould be put to other domestic uses, as they cannot be consumed directly

Spatial Variation of Throughfall in Two Tree Plantations in Abeokuta, South-Western Nigeria

Abstract This paper determined the variability of throughfall in two tree plantations on the campus of University of Agriculture, Abeokuta, South Western Nigeria. It involved the use of experimental plots consisting of Tectona Grandis and Gmeliba Arborea. Gross precipitation and thoughfall were measured and determined for a month. The data obtained was analysed using simple descriptive statistics such as means, percentages and frequency counts. Correlation analysis was used to determine the relationship between gross precipitation and throughfall under each tree plantation. Results show that Tectona plantation had more throughfall throughout the period of study than that of Grnelna plantation. Also there is a strong relationship between gross precipitation and throughtfall in the two plantation. The implication of the results for the management and use of water resources in the study area were discussed and recommendations made as to how water trapped through interception can be better managed

Multi-site calibration and validation of SWAT with satellite-based evapotranspiration in a data-sparse catchment in southwestern Nigeria

The main objective of this study was to calibrate and validate the eco-hydrological model Soil and Water Assessment Tool (SWAT) with satellite-based actual evapotranspiration (AET) data from the Global Land Evaporation Amsterdam Model (GLEAM_v3.0a) and from the Moderate Resolution Imaging Spectroradiometer Global Evaporation (MOD16) for the Ogun River Basin (20&thinsp;292&thinsp;km2) located in southwestern Nigeria. Three potential evapotranspiration (PET) equations (Hargreaves, Priestley–Taylor and Penman–Monteith) were used for the SWAT simulation of AET. The reference simulations were the three AET variables simulated with SWAT before model calibration took place. The sequential uncertainty fitting technique (SUFI-2) was used for the SWAT model sensitivity analysis, calibration, validation and uncertainty analysis. The GLEAM_v3.0a and MOD16 products were subsequently used to calibrate the three SWAT-simulated AET variables, thereby obtaining six calibrations–validations at a monthly timescale. The model performance for the three SWAT model runs was evaluated for each of the 53 subbasins against the GLEAM_v3.0a and MOD16 products, which enabled the best model run with the highest-performing satellite-based AET product to be chosen. A verification of the simulated AET variable was carried out by (i) comparing the simulated AET of the calibrated model to GLEAM_v3.0b AET, which is a product that has different forcing data than the version of GLEAM used for the calibration, and (ii) assessing the long-term average annual and average monthly water balances at the outlet of the watershed. Overall, the SWAT model, composed of the Hargreaves PET equation and calibrated using the GLEAM_v3.0a data (GS1), performed well for the simulation of AET and provided a good level of confidence for using the SWAT model as a decision support tool. The 95&thinsp;% uncertainty of the SWAT-simulated variable bracketed most of the satellite-based AET data in each subbasin. A validation of the simulated soil moisture dynamics for GS1 was carried out using satellite-retrieved soil moisture data, which revealed good agreement. The SWAT model (GS1) also captured the seasonal variability of the water balance components at the outlet of the watershed. This study demonstrated the potential to use remotely sensed evapotranspiration data for hydrological model calibration and validation in a sparsely gauged large river basin with reasonable accuracy. The novelty of the study is the use of these freely available satellite-derived AET datasets to effectively calibrate and validate an eco-hydrological model for a data-scarce catchment.</p

Desarrollo sostenible de las carreteras en África

Dallas Roadway Products (DRP) soil stabilization technology can effectively improve road foundation construction and with it the strength of roadway sub-grades and sub-bases. Soil samples were collected from roads in Nigeria’s six geo-political regions. DRP LS-40 (lignate sulfonate) and DRP SA-44 (sulfuric acid) were added to the soil materials. The mixture precipitated a non-reversible chemical reaction that involved a permanent change in the soil structure. The chemicals reacted with the clay content, increasing the soil material plasticity. In non-plastic soils, clay materials were added to the soil, which was then pulverised. The study showed that DRP soil stabilisation chemicals can render poor, unsuitable or marginally deficient soils apt for use as a sub-base or base in roadway construction.La tecnología de Dallas Roadway Products (DRP) constituye una metodología eficaz para mejorar la construcción de las capas inferiores del firme de calzadas y con ella la resistencia de las bases y sub-bases de las carreteras. En esta investigación se recogen muestras del terreno que constituye las carreteras existentes en las seis regiones geopolíticas nigerianas. Al incorporar a las muestras el DRP LS-40 (lignosulfonato) y el DRP SA-44 (ácido sulfúrico), la mezcla acelera una reacción química no reversible que produce una modificación permanente del entramado del suelo. La reacción de las sustancias químicas con la arcilla del suelo aumenta su plasticidad. A los suelos sin plasticidad se agregan materiales arcillosos, procediéndose a continuación a la pulverización del material resultante. Según los resultados obtenidos, las sustancias químicas de estabilización de suelos de DRP pueden transformar los suelos pobres, inapropiados o deficientes en materiales adecuados para servir como bases o sub-bases de las carreteras

Estimation of Water Balance of Oyan Lake in the North West Region of Abeokuta, Nigeria

The paper presents results related to water balance of the Oyan Lake in the North West in Nigeria. The catchment covering an area of 9000 km2 includes a small dam called Oyan dam having an effective watershed area of 40 km2 with a gross storage of 270 million cubic meters. Hydrology of the area was characterized on the basis of land use, rainfall, temperature, evaporation, evapotranspiration, and runoff using meteorological data. Different methods like rainfall coefficient method is used to determine monthly distribution of rainfall including rainy and dry months; Penman method to calculate evaporation from the reservoir; Thornthwaite method and Thornthwaite water balance model to determine potential and actual evapotranspiration; and runoff coefficient method to estimate runoff. The catchment is characterized by one rainy season and two dry seasons during the year. The rainy season has five months duration and dry season seven months. The mean annual rainfall of the catchment is 1015.09 mm, out of which rainy season accounts for 96.% and the dry season for 3.9%. The total annual water loss by evaporation from the reservoir is 1178.5 mm. The mean annual actual evapotranspiration for the catchment is 899.3 mm. The mean annual runoff generated from the catchment is estimated to be 822.2 million cubic meters. The amount of water that percolates into the ground in the catchment as groundwater is estimated to be about 219.9 million cubic meters, and the same at the reservoir site is 826.9 million cubic meters. The total amount of water which is actually available to recharge the groundwater within the catchment is 1046.8 million m3