African Journal of Environmental Science and Technology

Biosorption of fluoride ion from water using the seeds of the cabbage tree (Moringa stenopetala)

2017-01-27T16:56:35+00:00

Conventional water treatment technologies for the removal of fluoride ion may not be feasible for developing countries due to their high investment and operational costs. The aim of this study was therefore, to investigate the fluoride biosorption potential of the seeds of the cabbage tree (Moringa stenopetala). The influence of Moringa dosage, pH, contact time, and initial concentration of fluoride ion was investigated. The maximum fluoride sorption capacity was found to be 1.32 mg.g^-1 of dry weight of Moringa seeds at a biomass dosage of 2 g L^-1, pH 7.00, initial fluoride ion concentration of 10 mg.L^-1 and a contact time of 60 min. The fluoride level was reduced from 10 to 3.4 mg L^-1. The adsorption of fluoride ion onto Moringa powder was best described by the pseudo-second-order kinetic model (R2 = 0.99). The
adsorption equilibrium data have been fitted well to Langmuir as well as Freundlich adsorption models (R2≥0.97 for both models). The distribution constant (K_d) and maximum adsorption capacity (Bmax) were significantly influenced by the amount of Moringa and equilibrium fluoride ion concentration (p<0.05). The desorption tests indicated that only 20% of the initially bound fluoride ion was regenerated, while the remaining 80% were bounded with the Moringa powder. This suggests that chemisorption was the possible mechanism of fluoride removal.

Key words: Biosorption, chemisorption, desorption, fluoride, isotherm, Moringa stenopetala.

The impact of septic systems density and nearness to spring water points, on water quality

2017-01-27T16:56:37+00:00

Worldwide, 1.1 billion people do not have access to clean water and as a result, 2 million children die annually due to preventable waterborne diseases. In Uganda, 440 Children die every week of waterborne diseases. High prevalence of this death is reported in the peri urban areas. It is still unclear however the causes of water pollution in the peri-urban areas. The improper use of onsite sanitation facilities such as latrines and septic systems may lead to groundwater contamination. It is true that drain field of septic system located too close to water point, and or over population of the septic systems in a small area can lead to pollution of groundwater. Our study investigated the impact of septic systems density and nearness to water points on spring water quality. Samples from 15 spring wells were analysed for pH, nitrate and faecal coliform contamination. Locations and distances of spring from septic systems were determined using global positioning system (GPS) device and ArcGIS software, respectively. Water samples from all the spring wells had pH value less than 6.5, 66.7% had faecal coliform and 53% had nitrate above 2 mg L^-1. While sample from one of the springs had nitrate concentration above the United States Environmental Protection Agency (US EPA) standard of 10 mg L^-1. It was also noted that coliform counts and nitrate concentrations increases with increase in number of septic systems surrounding the spring well. In addition, increase in distance between spring wells and septic systems indicated decrease in both coliform counts and nitrate concentration. It is therefore concluded that improper use of septic systems is one of the causes of groundwater pollution in the peri urban areas. The study recommends treatments of water from groundwater sources, regular monitoring of groundwater sources and proper design and siting of septic systems using more robust methodologies.

Key words: Spring water quality, septic systems density, proximity to spring, coliform, nitrate.

The earthquake/seismic risk, vulnerability and capacity profile for Karonga town

2017-01-27T16:56:38+00:00

The study was carried out to understand the risks posed by earthquakes in Karonga based on roles and perception of stakeholders. Information was collected from several stakeholders who were found responding to earthquakes impacts in Karonga Town. The study found that several stakeholders, governmental and non-governmental department and organisation operate in Karonga District to respond to hazards and disasters that occur in the district however most of these stakeholders concentrate their activities in rural areas than the town despite having the town experiencing greater impacts from earthquake hazards. The study also found that people of Karonga are aware of earthquakes and how they can avoid their impacts however their economic status fail them from developing infrastructure that can help them to avoid or recover quickly from the impacts of earthquake disasters. It is therefore concluded that the people of Karonga town are vulnerable to earthquake hazards due to limited capacity to develop appropriate infrastructure that can survive seismic hazards.

Key words: Earthquake, seismic, risk, vulnerability, capacity.

Preliminary study on climate seasonal and spatial variations on the abundance and diversity of fungi species in natural plantation ecosystems of Ile-Ife, South West, Nigeria

2017-01-27T16:56:39+00:00

The biodiversity assessment of fungi and the knowledge of the forces that controls the distribution of fungi and their community are becoming more important in the light of climate change and variability. Fungi provide the global foundation for plant as mutualists, decomposers and pathogens. This study deals with the primary screening, characterization and seasonal variations of mycoflora, isolated from medicinal, oil palm and plantain plantations of the Obafemi Awolowo University, Ile-Ife, Nigeria, from February to June. Fungi colonies and different fungal species were screened and identified across different months and weather variability. Data on the weather variations were collected. Soil samples (0 to 30 cm depth) were collected at different locations within the rhizosphere in each plantation, and the physico-chemical properties and fungi microbial load were determined using standard techniques. The result of soil physico-chemical properties showed that the soil type was humus and acidic in nature. A total of 8 fungi genera and 33 species were recorded in the studied plantations. Temperature of the studied areas ranged between 22.5 to 31.06°C, while the relative humidity of the studied sites ranged from 54.6 to 100%. The rainfall data obtained in this study ranged between 0.381 to 0.584 m. The highest microbial load was (8 × 105 CFU/g) and was observed under medicinal plantation in the month of June. The results obtained showed that weather variability’s have direct effect on different fungal species sporulation and CFU formation.

Key words: Climate, fungi, soil, microbial load, natural plantation.

Comparative study of soil physical characteristics of Jaipur district, Rajasthan

2017-01-27T16:56:41+00:00

Increasing trend in the frequency of natural events like floods and drought, etc. due to increasing urbanisation has led to degradation of the ecosystems. A major flood in year 1981 in Jaipur district resulted into huge erosion of the top fertile soil and leaving the land unproductive for agriculture production. The present study was carried in Jaipur district of Rajasthan state to measure physical characteristics of the soil samples from different districts of Jaipur. Soils samples were taken at 5 and 15 cm below the top surface and have taken 3 samples per site in each month. The soil physical parameters like sieve analysis, dry density, liquid limit, specific gravity and moisture content were analysed by standard techniques for different months in a year. Analysed results revels that, land cover having different characteristics has an impact on the temporal variability of soil moisture and other physical variables. The result of this will help to understand the variation of physical properties and thus to better planning to work in agricultural field. Further to say that, findings of the study can be used for altered case studies, concentrating on the soil variability effects for geotechnical issues.

Key words: Flood, physico-chemical, water content, specific gravity, geotechnical.

Effect of discharges from re-channeled rivers and municipal runoff on water quality of Opa reservoir, Ile- Ife, Southwest Nigeria

2017-01-27T16:56:42+00:00

Over the years, there is a direct linkage of township drains and streams to the Opa reservoir, Obafemi Awolowo University, Nigeria. Hence the spatial and temporal variations of the reservoir’s water quality were studied between November 2012 and October 2013 to investigate the effect of these discharges on these. Physical, chemical as well as the oxygen parameters of the water were investigated using standard techniques. The parameters determined revealed considerable temporal variations with the rainy season averaged concentration of COD, TOC, OM, TSS, TS, turbidity, apparent colour, true colour, sodium, and phosphate significantly higher (p<0.05) than those of the dry season. Spatially, DO, TSS,TS, organic matter and TOC decreased significantly (p<0.05) from riverine to the lacustrine (dam site). However, calcium, sulphate, and electrical conductivity showed significant increases (p<0.05) from the riverine zone section towards the dam site. Vertically, sulphate, bicarbonate, COD, TOC, chloride, TSS, TS, turbidity, apparent colour, true colour and sodium ion values increased significantly (p<0.05) from the surface down to the bottom. Conversely, magnesium, total hardness, nitrate, BOD, DO, electrical conductivity, acidity, carbonate, alkalinity, TDS and pH values decreased (p<0.05) from water surface to the bottom of the reservoir. Therefore, the discharges from the catchment area of Opa reservoir could pose a level of risk to the aquatic ecosystem as well as the community if not well treated before being supplied.

Key words: Spatial, temporal, water quality, zones, risk level, source.

Eggshells – assisted hydrolysis of banana pulp for biogas production

2017-01-27T16:58:51+00:00

In this study, pretreatment of banana pulp using eggshells in both calcined and un-calcined forms to examine the extent of hydrolysis was conducted. Reactor CO containing banana pulp and inoculum but with no eggshells added was used as the control, while reactors C₁, C₂, C₃, C₄, and C₅ containing banana pulp and inoculum were spiked with 1, 3, 5, 7, and 9 g of un-calcined eggshells and calcined eggshells, for experiment 1 and 2, respectively. Anaerobic digestion was carried out at mesophilic temperature (35°C) for a period of 20 days. Digester C₃ with 5 g of calcined eggshells gave the largest cumulative biogas yield of 2343 mL with 62% CH₄, follow. The least biogas yield of 10 mL was obtained in digester C₅with 9 g of calcined eggshells additive.

Key words: Anaerobic digestion, banana pulp hydrolysis biogas, eggshells.

Aerobic mineralization of selected organic nutrient sources for soil fertility improvement in cambisols, Southern Ethiopia

2017-01-27T16:56:45+00:00

No Abstract.

Key words: Ammonium, incubation, mineralization, nitrate.

Effects of different fertilizers on methane emission from paddy field of Zhejiang, China

2017-01-27T16:56:46+00:00

No Abstract.