Assessment of the change in river discharge-carrying capacity using remote sensing geographic information system: a case study of Ofu river, Nigeria

This study assessed the changes in the flow carrying capacity of Ofu River in Nigeria between 2000 and 2011 using the DEMs of the respective years. The results showed that Ofu River had lost 12.88 m amounting to about 42.58 % of its flow depth at Oforachi between 2000 and 2011 at a rate of 1.171 m per year and an estimated 18.74 m amounting to about 61.95 % in 2016. The Total sediment load was 66,825,730 kg/year comprising of 56,747,260 kg/year and 10,077,470 kg/year of measured and unmeasured sediment loads respectively. The results obtained suggested that the loss in flow depth is a result of siltation of the river bed due to the high sediment load probably as a result of soil cultivation within the floodplains. The study demonstrated that remote sensing and GIS can be used to assess the changes in the discharge-carrying capacity of a river.Keywords: DEM, Discharge capacity, Flow depth, GIS, Ofu river, Sediment loa

Reliability assessment of Thomas Fiering's method of stream flow prediction

This study was carried out to assess the reliability of Thomas-Fiering’s method of stream flow prediction. The 19 years gauged data of 1955-1973 was extended to 2016 using the model. Model calibration was done by multiple linear regressions of the gauged and synthetic data of 1956-1973. The linear equations developed for January to December were used for adjustment of the three sets of stream flow data generated for 1974-2016. The reliability assessment was done based on the extent to which the unbiased statistics (mean, standard deviation and correlation coefficients) of the 1955-1973 stream flow data were preserved in the synthetic stream flow for 1955-2016. The comparison was done using linear regression and One-Way ANOVA (95% Confidence level) to check for the reliability of the generated data. The coefficients of determination, P-values, F-values and critical F-values were used to estimate the reliability index. Synthetic data was found to be 95.9% reliable.Keywords: Ofu River, Reliability, Stream flow, Synthetic, Thomas Fiering’s mode

Modifikasi Metode Linear Congruential Generator Untuk Optimalisasi Hasil Acak

Pelaksanaan ujian secara konvensional dianggap kurang efektif dan efisien karena membutuhkan biaya yang besar dan waktu yang lama dalam pelaksanaannya sehingga perlu dilakukan perbaikan dengan mengubah sistem ujian menjadi komputerisasi. Dalam setiap pelaksanaan ujian perlu memperhatikan tindak kecurangan yang dilakukan siswa berupa mencontek dan kerja sama bertukar jawaban. Penelitian ini bertujuan untuk memberikan soal acak yang berbeda kepada setiap siswa dengan menggunakan metode Linear Congruential Generator (LCG). Akan tetapi penggunaan metode LCG masih memiliki kelemahan dimana hasil pengacakan mudah ditebak sehingga perlu adanya optimalisasi pengacakan yaitu menggunakan dua LCG dan bantuan matrik yang menjadi metode Coupled Linear Congruential Generator (CLCG). Metode modifikasi CLCG menghasilkan pengacakan yang lebih baik dan pola yang lebih rumit dibandingkan dengan metode LCG

EVALUATION OF BIOGAS POTENTIALS OF Cymbopogon citratus AS ALTERNATIVE ENERGY IN NIGERIA

This research explored the potentials of Cymbopogon citratus (Lemon Grass) for biogas production as a cost effective alternative energy source in Nigeria. The Cymbopogon citratus was crushed to small sizes between 20 to 50mm and pre-fermented for 40 days in a PVC drum. Six (6) kg of the pre-fermented Cymbopogon citratus was mixed with water in ratio 1:1 w/v to form slurry and digested for 30 days. The floating drum gas collection system was used to collect the gas after it was passed through water and lime respectively for scrubbing. A total of 0.125m3 (6.95x10-4 m3/kg/day) and 0.0897m3 (4.98x10-4 m3/kg/day) of biogas was produced from the Cymbopogon citratus before and after scrubbing respectively. The gas produced was used for cooking test. The scrubbed gas had higher cooking rates for both water and rice respectively (0.12L/min and 0.0052L/min) while the cooking rates for unscrubbed gas were 0.079L/min and 0.0036L/min respectively. During this period, daily ambient temperatures of the research environment varied from 310C to 420C while the digester temperature fluctuated between 28oC and 36.70C. The pH of the medium fluctuated optimally between 6.5 and 7.8. The research demonstrated that Biogas could be produced from Cymbopogon citratus in quantity and quality comparative with those in literatures

Assessment of Infiltration Rates and Index Properties of Soil in a Flood Prone Community, Kogi State, North Central Nigeria

The characteristics of Soil is one of the major factors that affect flooding. This study therefore was carried out to assess the infiltration rates and index properties of soil within a flood-prone community of Oforachi in Kogi State, Nigeria using appropriate standard methods. Data obtained showed that the average soil infiltration rate ranges from 1.89 – 3.24 cm/hr and the maximum infiltration rate range between 6.00 – 9.00 cm/hr, while the soil antecedent moisture content was between 15.00 – 42.48 %. Soil infiltration properties classification based on hydraulic conductivity and sieve analysis show that soils within the study area combine silt and clay characteristics which has strong relationship with the persistent flood experienced in the area

Fertilizer and Sanitary Quality of Digestate Biofertilizer from the Co-digestion of Food Waste and Human Excreta

This research was aimed at assessing the fertilizer quality and public health implications of using digestate biofertilizer from the anaerobic digestion of food wastes and human excreta. Twelve (12) kg of food wastes and 3 kg of human excreta were mixed with water in a 1:1 w/v to make 30-l slurry that was fed into the anaerobic digester to ferment for 60 days at mesophilic temperature (22–31 �C). Though BOD, COD, organic carbon and ash content in the feedstock were reduced after anaerobic digestion by 50.0%, 10.6%, 74.3% and 1.5% respectively, nitrogen, pH and total solids however increased by 12.1%, 42.5% and 12.4% respectively. The C/N ratios of the feedstock and compost are 135:1 and 15.8:1. The residual total coliforms of 2.10 � 108 CFU/100 ml in the digestate was above tolerable limits for direct application on farmlands. Microbial analysis of the digestate biofertilizer revealed the presence of Pseudomonas, Klebsiella, Clostridium, Bacillus, Bacteroides, Penicillum, Salmollena, and Aspergillus. Klebsiella, Bacillus, Pseudomonas, Penicillum and Aspergillus can boost the efficiency of the biofertilizer through nitrogen fixation and nutrient solubility in soils but Klebsiella again and Salmollena are potential health risks to end users. Further treatment of the digestate for more efficient destruction of pathogens is advise

Assessment of the Effect of Land Use /Land Cover Changes on Total Runoff From Ofu River Catchment in Nigeria

The total runoff from a catchment is dependednt on both the soil characteristics and the land use/land cover (LULC) type. This study was conducted to examine the effect of changes in land cover on the total runoff from Ofu River Catchment in Nigeria. Classified Landsat imageries of 1987, 2001 and 2016 in combination with the soil map extracted from the Digital Soil Map of the World was used to estimate the runoff curve number for 1987, 2001 and 2016. The runoff depth for 35 years daily rainfall data was estimated using Natura Resource Conservation Services Curve Number (NRCS-CN) method. The runoff depths obtained for the respective years were subjected to a one-way analysis of variance at 95% level of significance. P-value < 0.05 was taken as statistically significant. Runoff curve numbers obtained for 1987, 2001 and 2016 were 61.83, 63.26 and 62.79 respectively. The effects of the changes in LULC for 1987-2001, 2001-2016 and 1987-2016 were statistically significant (P<0.001) at 95% confident interval. The average change in runoff depths were 79.81%, -11.10% and 48.09% respectively for 1987-2001, 2001-2016 and 1987-2016. The study concluded that the changes in LULC of the catchment had significant effect on the runoff from the catchment

Performance Evaluation of Waste Stabilization Pond for Treatment of Wastewater from a Tertiary Institution Campus Located in Jos North Local Government Area, Plateau State, Nigeria

Appropriate treatment of wastewater before disposal into the environment or reuse is very important in the quest to protect the environment and safeguard public health. This paper investigated the performance evaluation of a waste stabilization pond (WSP) for treatment of wastewater from a tertiary institution campus located in Jos North Local Government Area of Plateau State in North Central Nigeria. The waste stabilization pond of the tertiary institution campus was designed for a wastewater flow rate of 12,945 m3/day. In order to evaluate the performance of the WSP, a model was developed following the Froude’s number dimensional analysis technique. The model was evaulated based on a wastewater flow of 0.4 m3/day. The final effluent from the maturation pond had 80 mg/L BOD, 195 mg/L COD, 75 CFU/100ml Total Coliforms, 610 mg/L Total solids, 19 mg/L Total Nitrogen, 210 mg/L Chloride, 28 mg/L Phosphate, 1.3 mg/L Ammonia and 7.0 pH. The WSP was able to achieve an overall efficiency of 77.78% reducing all quality parameters to recommended limited with exception of total nitrogen and phosphate. The implementation of this design will go along way to aid the treatment of wastewater from the campus of the university

Application of Analytic Hierarchy Process and Geographic Information System Techniques in Flood Risk Assessment: A Case of Ofu River Catchment in Nigeria

Flood risk assessment of Ofu River Catchment in Nigeria was carried out by integration of thematic maps in ArcGIS 10.2.2. Analytic Hierarchy Process (AHP) was applied in the decision making and ranking of flood causative factors before their integration for development of hazard map in ArcGIS. The social and physical vulnerability of the catchment were considered in the development of the vulnerability map. The flood risk map was developed as a product of the hazard and vulnerability map. The results showed that the land areas within the Very High and High Risk zones were respectively 163.07 km2 and 392.63 km2 with Igalamela/Odolu Local Government Area (LGA) accounting for about 62% and 31% respectively. A total of 19, 034 and 47,652 persons are respectively at very high and high risk of flood within the catchment. Oforachi community in Igalamela/Odolu LGA and Ejule Ojebe Community in Ibaji LGA both in Kogi State are respectively at Very High and High Risk of Ofu River flood. High Impacts were recorded by about 35% and 52% of Oforachi Community during the 1995 and 2000 historical flood events. A watershed management plan is therefore required to prevent the serious damage experienced in previous flood events

Optimization of biogas from chicken droppings with Cymbopogon citratus

Optimization of biogas production and quality from chicken droppings by anaerobic co-digestion withCymbopogon citratuswas investigated. The anaerobic digestions of chicken droppings, chicken droppingswithC. citratusas well asC. citratusalone were carried out for a period of 30 days at an average ambienttemperature of 33.1�2�C using identical reactors (AeC) respectively. Results obtained indicate thatchicken droppings produced on the average 1.8 L/kg/day of biogas, co-digestion of chicken droppings andC. citratusproduced 1.3 L/kg/day of biogas whileC. citratusalone produced 1.0 L/kg/day with estimatedaverage methane content of 41.71%, 66.20% and 71.95% for reactors AeC respectively. The water boilingrates of biogas from chicken droppings, chicken droppings withC. citratus, andC. citratusalone were0.079 L/min, 0.091 L/min and 0.12 L/min respectively, after the gases were scrubbed with water andslaked lime. It was observed that notwithstanding the higher biogas volumetric yield from chickendroppings digested alone, the co-digestion of chicken droppings withC. citratushad better gas qualitywith respect to the methane content present and cooking rate. This study has shown that the methanecontent of biogas from animal manure substrates could be improved by co-digestion with energy plant