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Open Access
Approaches to the Evaluation of Teaching and Learning Methods at a University: Evidence from South Africa
(2017) Gumbo, Jabulani R.
An increasing number of students drop out of university in South Africa and throughout the world. The South African Council for Higher Education has introduced strategies to deal with high dropout rates, which include the improvement of teaching and learning through the Quality Enhancement Program. I hereby document and evaluate my teaching and learning methods. The data collection for this research involved student informal evaluation, formal evaluation and peer evaluation. The formative evaluation data was grouped in 14 themes with numbers in brackets representing the number of counts of student expression of [their free form]: good lecturer (51); stop pointing (12); request for softcopy of lecture notes (7); speak with a loud voice (5); time to write notes (4); field work/practicals (2);; do not understand lecture notes (2); lecturer coming late (2); lots of lectures notes and case studies are long (2); update notes (1); no double class on Friday (1); timetables are clashing (1); require a small tests (1); revision of lecture (1). The concerns for summative evaluation were: I was a good lecturer; issues on hard copies of lecture notes and feedback on assignments. With regard to peer evaluation, a fellow academic attended one of my lectures to make observations and review the teaching and learning procedures. I was able to observe that I ended my lectures too abruptly. As a result, the suggested approach was that gradually end the lectures with a series of questions that invoke a critical response from students and ask any student to summarize the lecture in three sentences. I have since implemented the student concerns.
Open Access
Asessing the Quality of Traditionally Manufactured Ceramic Water Filters, Limpopo, South Africa
(2017-11-28) Gumbo, Jabulani R.; Munarini, Asivhanzhi I.; Khangale Ndishavha
The traditional clay pot can be modernized by including sawdust to produce a ceramic water filter. Ceramic water filters are known to improve the quality of drinking water by inactivating waterborne pathogens. Here we report on the quality of traditionally manufactured ceramic water filter in improving the chemical and microbial quality of drinking water. The sources of drinking water were Mambedi dam and the Luvuvhu River. The water from Luvuvhu River was then filtered with ceramic water filter (CWF). The mean pH values of Luvuvhu River and purified water ranged from 6.20 to 6.56 and 7.79 to 7.91 respectfully. The electrical conductivity of Luvuvhu River and purified water ranged from 210 to 224 μS/cm and 229 to 284 μS/cm respectfully. The temperature of Luvuvhu River and purified water ranged from 21.3 to 23.5 °C and 23.1 to 25.5°C respectfully. The turbidity mean value of Luvuvhu River and purified water ranged from 1.67 to 4.38 NTU and 0.31 to 0.64 NTU respectfully. The CWF was effective in the removal of some metals Cr, Sr, and Ba and there was no leaching of metals As and Ni. The total coliforms and faecal coliforms in the purified water were 3 cfu/100 ml and 36 cfu/100 ml respectfully. Thus at household level, the ceramic water filter may be used to improve the chemical and microbial safety of the Luvuvhu river.
Open Access
Assessment of As and Hg in mine tailings and indigenous grass : a case study of non-functional New Union Gold Mine, South Africa
(2015) Mundalamo, Tsedzuluso; Gumbo, Jabulani R.; Muzerengi, Confidence; Dacosta, Francis
The present study was carried out to assess the uptake of toxic metals, arsenic (As) and mercury (Hg), by Cynodon dactylon grass species at New Union gold mine tailings, Limpopo Province, South Africa. The samples were collected from New Union Gold Mine tailings and from Ka-Madonsi Village (control), and concentrations of As and Hg in soil and plant material were determined by ICP-MS. The average dry weight concentrations of As and Hg in mine tailing dam A were 2.53 and 1.18 µg/g, respectively, and 2.24 and 0.91 µg/g, respectively, in mine tailings B. The average dry weight of As and Hg in the control soil samples were 0.30 and 0.05 µg/g, respectively. The C. dactylon, on average dry weight, absorbed 5.45 µg/g of As, and 1.72 µg/g of Hg from mine tailings A, and 4.29 µg/g of As; and 1.55 µg/g of Hg from mine tailings B. The control grass, on average dry weight, absorbed 0.53 µg/g and 0.01 µg/g of As and Hg, respectively. In most cases, significant differences were observed between bioaccumulation of Hg and As in plant tissue from mine sites and control sites. The study showed that the bioconcentration factor was less than 1 for the acidic mine tailings, with exception of the root and rhizome system which was greater than 1. This contrasted sharply with the control site where the pH was alkaline, and As and Hg levels were low. The pH values were significantly different (p <0.05) between the soils originating from mine tailings and the control site. The electrical conductivity (EC) of soil at mine tailings A and B were 1847.35 and 1777.5 µS/cm, respectively. The EC for the control site was significantly different (p < 0.05) at 543.3 µS/cm. C. dactylon was found to be capable of bioaccumulation of As and Hg, effective at soil stabilization, and grew well under the acidic conditions. The control grass was healthy and thrived under the alkaline conditions.
Open Access
Defluoridation of groundwater using diatomaceous earth : optimization of adsorption conditions, kinetics and leached metals risk assessment
(Taylor and Francis, 2015-08-27) Izuagie, Anthony A.; Gitari, Wilson M.; Gumbo, Jabulani R.
In Sub-Saharan Africa, many rural communities depend on boreholes as the most appropriate source of water supply. Sadly, water from some of the boreholes contains ﬂuoride above the WHO guideline of 1.5 mg/L. Hence, deﬂuoridation is necessary. The aim of this study is to investigate the ﬂuoride uptake capacity of diatomaceous earth (DE), a natural resource at optimized conditions by batch method. X-ray ﬂuorescence analysis showed that the major component is silica (83.1%), while Al2O3 is the main minor component. XRD shows it is an amorphous material. For 8 mg/L ﬂuoride spiked water, the highest per cent ﬂuoride removal at optimum adsorption conditions (contact time: 30 min, adsorbent dosage: 8 g/L, pH 2, temperature: 298 K and shaking speed: 200 rpm) was between 23.4 and 25.6%. PO3 4 in tested ﬁeld water was observed to reduce the ﬂuoride uptake capacity of ﬂuoride. The sorption data ﬁtted better into Freundlich isotherm than Langmuir isotherm. Fluoride sorption process was found to be a second-order kinetic. Inductively coupled plasma-mass spectrometer analysis of treated water revealed that metal and non-metal species were released at trace levels. Modiﬁcation of DE would be necessary to enhance the ﬂuoride adsorption capacity
Open Access
Effects of calcination temperature and solution pH on the defluoridation potential of Al/Fe oxide-modified diatomaceous earth: metal leaching and sorbent reuse
(IWa Publishing, 2017) Izuagie, Anthony A.; Gitari, M.; Gumbo, Jabulani R.
An evaluation of the effects of calcination temperature and solution pH on the fluoride removal capacity of Al/Fe oxide-modified diatomaceous earth was carried out. The sorbent was observed to be most effective and stable within the pH range 6.70–8.12, where the lowest concentrations of Al and Fe (<1 mg/L) in treated water were recorded. Thus, sorbent loss was minimal at that pH range. It was observed that the sorbent lost its efficiency and stability at calcination temperatures above 600 WC. Inductively coupled plasma-mass spectrometer analysis of metals in supernatants and thermogravimetric analysis of the sorbent showed that there was substantive loss of Al and Fe from the sorbent at temperatures above 600 WC because of evaporation. K2SO4 solution proved to be the best regenerant for spent sorbent compared to NaOH and Na2CO3, which caused sorbent loss owing to high solution pH. The CO2 3 from Na2CO3 bound to regenerated sorbent so much that it could not be displaced by fluoride during subsequent defluoridation experiments. Sorbent regenerated with 0.1 M K2SO4 solution could reduce 10 mg/L fluoride in artificial water at a dosage of 0.8 g/100 mL by 81.8% and 67.2% at the second and third cycles, respectively.
Open Access
Impact on water quality of Nandoni Water Reservoir Downstream of municipal sewage plants in Vhembe District, South Africa
(2016-06-24) Gumbo, Jabulani R.; Dzaga, Ratshilumela Aaron; Nethengwe, Nthaduleni Samuel
Open Access
Synthesis and performance evaluation of AI/Fe oxide coated diatomaceous in groundwater defluoridation : towards fluoris mitigation
(Taylor and Francis, 2016-05-24) Izuagie, Anthony A.; Gitari, Wilson M.; Gumbo, Jabulani R.
The quest to reduce ﬂuoride in groundwater to WHO acceptable limit of 1.5 mg/L to prevent diseases such as teeth mottling and skeletal ﬂuorosis was the motivation for this study. Al/Fe oxide-modiﬁed diatomaceous earth was prepared and its deﬂuoridation potential evaluated by batch method. The sorbent with pHpzc 6.0 § 0.2 is very reactive. The maximum 82.3% ﬂuoride removal attained in 50 min using a dosage of 0.3 g/100 mL in 10 mg/L ﬂuoride was almost attained within 5 min contact time; 81.3% being the percent ﬂuoride removal at 5 min contact time. The sorbent has a usage advantage of not requiring solution pH adjustment before it can exhibit its ﬂuoride removal potential. A substantial amount of ﬂuoride (93.1%) was removed from solution when a sorbent dosage of 0.6 g/100 mL was contacted with 10 mg/L ﬂuoride solution for 50 min at a mixing rate of 200 rpm. The optimum adsorption capacity of the adsorbent was 7.633 mg/g using a solution containing initially 100 mg/L ﬂuoride. The equilibrium pH of the suspensions ranged between 6.77 and 8.26 for 10 and 100 mg/L ﬂuoride solutions respectively. Contacting the sorbent at a dosage of 0.6 g/100 mL with ﬁeld water containing 5.53 mg/L at 200 rpm for 50 min reduced the ﬂuoride content to 0.928 mg/L—a value below the upper limit of WHO guideline of 1.5 mg/L ﬂuoride in drinking water. The sorption data ﬁtted to both Langmuir and Freundlich isotherms but better with the former. The sorption data obeyed only the pseudo-second-order kinetic, which implies that ﬂuoride was chemisorbed
Open Access
Willingness to pay for water services in two communities of Mutale Local Municipality, South Africa : a case study
(2015) Rananga, H. T.; Gumbo, Jabulani R.
The provision of reliable and adequate drinking water services in rural communities is important. Here, the researchers reported on a study that evaluated the respondents’ willingness to pay for water services in the two communities in Mutale Local Municipality, South Africa. The study was accomplished through open-ended questionnaire interviews with selected respondents. The study showed that respondents were dissatisfied with the unreliable water services (89.9%) but were willing to pay for water services to secure reliable water services (95.5%). The respondents with tertiary level education were willing to pay R 150 per month per 6 kilolitres. The maximum 6 kilolitres is the free basic water services that the municipality can provide without collecting water revenues. The following variables: literacy levels; household size of 3 to 6 members; the age of 40; and monthly incomes, had a significant effect (p = 0.005) on the monetary amount and the willingness to pa

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