scholarly journals Treatment of AMD using a combination of saw dust, bentonite clay and phosphate in the removal of turbid materials and toxic metals

2021 ◽  
Author(s):  
I. O. Ntwampe
Keyword(s):  
South Africa ◽  
Particle Size ◽  
Removal Efficiency ◽  
Toxic Metals ◽  
Laboratory Experiments ◽  
Mine Drainage ◽  
Bentonite Clay ◽  
Small Scale ◽  
Saw Dust ◽  
Natural Organic Compounds

Abstract Acid mine drainage collected from the western decant in South Africa was treated in a series of small-scale laboratory experiments. 200 mL of the sample was poured into five 500 mL glass beakers using flocculants formed by mixing size-optimized 1.5 g of bentonite clay with 3.5 g saw dust and 1.0 g of Na3PO4 in triplicates (experiment A). Four similar sets of control experiments were conducted using the same amount of bentonite clay and saw dust with varying Na3PO4, contents in AMD treatment; the rationale being to determine the efficiency of Na3PO4 (experiments B, C and D). The results show that conductivity has an influence in the removal of the turbid materials. The removal efficiency of toxic metals using a flocculant containing 220 μm bentonite clay particle size and 0.012 or 0.25 M of Na3PO4 is higher than 96% when compared to that of the samples dosed with a flocculant containing 0.05 M Na3PO4, which is less than 91%. The flocculent also showed optimal removal efficiency of both turbid materials and toxic metals, i.e. removal efficiency within a range 96.5–99.3%. The flocculants containing 0.025 M Na3PO4 showed optimal removal efficiency of turbidity, colour, toxic metals and natural organic compounds.

scholarly journals The removal of pollutants and natural organic compounds from acid mine drainage using a combination of bentonite clay and MgSO4

2021 ◽  
Vol 16 (2) ◽  
pp. 490-503
Author(s):  
I. O. Ntwampe
Keyword(s):  
Acid Mine Drainage ◽  
Organic Compounds ◽  
Removal Efficiency ◽  
Mine Drainage ◽  
Bentonite Clay ◽  
Small Scale ◽  
Acid Mine ◽  
Jar Test ◽  
Oxidation Reduction ◽  
Natural Organic Compounds

Abstract 200 mL of synthetic acid mine drainage (AMD) sample was poured into five 500 mL glass beakers and treated in a jar test and a shaker in sets of experiments, respectively. The samples were treated in small-scale laboratory experiments using synthetic AMD sample dosed with bentonite clay and MgSO4 respectively, and a flocculant consisting of the same reagents. The pH, EC, turbidity and oxidation reduction potential were measured. The removal of turbid materials in the samples dosed with a flocculant is higher compared to those of the samples dosed with each reagent alone. The samples with flocculant dosage show high removal efficiency of natural organic compounds and toxic metals, slightly higher compared to those with a dosage of a combination of bentonite clay and MgSO4. The removal efficiency of the samples treated in a shaker is better than those with rapid mixing. The SEM micrographs show sorption is a physico-chemical phenomenon.

scholarly journals The removal of turbidity and toxic metals in the AMD using a combination of saw dust, bentonite clay and synthetic CaMg.2(OH)2

2021 ◽  
Author(s):  
I. O. Ntwampe
Keyword(s):  
Toxic Metals ◽  
Mine Drainage ◽  
Bentonite Clay ◽  
Lower Percentage ◽  
Turbidity Removal ◽  
Saw Dust ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Sem Micrograph ◽  
Oxygen Oxidation

Abstract Sets of experiments were conducted using 200 mL of synthetic acid mine drainage(AMD) into five 500 mL glass beaker, dosed with varying quantities of bentonite clay, saw dust and CaMg.2(OH)2 respectively and as a flocculent (bentonite clay, saw dust and CaMg.2(OH)2), mixed at 250 and 100 rpm for 2 and 10 mns respectively. The samples settled for 1 hour after which the pH, conductivity, turbidity, dissolved oxygen, oxidation reduction potential and toxic metals were measured. The turbidity removal of treated AMD samples treated with a flocculent (0–23 NTU) is lower compared to that of the samples treated with bentonite clay and saw dust (27–32 NTU). Results show 100% removal of Ni, moderate percentage removal of Fe and slightly lower percentage of Cu in treated AMD using a flocculent. Turbidity removal in treated AMD using a flocculent is higher compared to that of the samples treated with bentonite clay, saw dust or CaMg.2(OH)2. Treated AMD using flocculent has low Ca, Mg, Cl− and SO42− content (>84.8%). The SEM micrograph of the sludge of the sample with a combination of 1.5 bentonite clay, 1.5 g saw dust and 20 mL 0.025 M CaMg.2(OH)2 dosage shows optimal sorption of turbid materials.

scholarly journals The removal of turbid materials from AMD using bentonite clay, Fe or Al salt, MgCO3 and flocculent with varying agitations

2020 ◽  
Vol 15 (3) ◽  
pp. 580-597
Author(s):  
I. O. Ntwampe
Keyword(s):  
Removal Efficiency ◽  
Mine Drainage ◽  
Bentonite Clay ◽  
Jar Test ◽  
Oxidation Reduction ◽  
Treated Effluent ◽  
Oxidation Reduction Potential ◽  
Changing Trend ◽  
Series Of Experiments ◽  
Slow Mixing

Abstract A series of experiments was conducted using 200 mL of acid mine drainage (AMD) collected from Krugersdorp, South Africa, to determine turbid materials removal efficiency of a combination of bentonite clay, Fe or Al salt and MgCO3. The sample was poured into five 500 mL glass beakers using bentonite clay, FeCl3, AlCl3 and MgCO3 dosage respectively. The samples were treated in jar test at rapid and slow mixing, allowed to settle for 1 hour, then the pH, conductivity, total suspended solids (TSS), dissolved oxygen (DO) and oxidation reduction potential (ORP) were measured (exp A). A second and third similar sets of experiments were conducted with a combination of bentonite clay and MgCO3 (flocculent) dosage (exp B), and FeCl3 with slow mixing only (exp C). Experimental results revealed that the pH of treated effluent with bentonite clay does not exhibit significant increasing trend because of insignificant hydrolysis, whereas the pH of samples with FeCl3, AlCl3 and MgCO3 exhibit a slight decreasing trend, showing a low rate of hydrolysis. The DO and ORP of treated effluent does not show a significant changing trend compared to the untreated AMD sample. Residual TSS of the AMD samples treated with a flocculent is lower than the samples treated with bentonite clay, FeCl, AlCl3 and MgCO3. Residual turbidity of the samples with rapid mixing is identical to that of the corresponding samples with slow mixing. TSS removal efficiency of a flocculent is higher compared to other reagents. The results show that synthetic flocculent is an ideal replacement for inorganic coagulants. The scanning electron microscopy (SEM) micrographs exhibit slides with dense-sponge like flocs showing high adsorption capacity.

scholarly journals Assessing the clogging and permeability of degrading packed bed reactors

Water SA ◽  
2018 ◽  
Vol 44 (1 January) ◽  
Author(s):  
Anthin Botes ◽  
Chris James ◽  
Craig M Sheridan
Keyword(s):  
South Africa ◽  
Water Treatment ◽  
Mine Drainage ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Small Scale ◽  
Mining Sector ◽  
Wood Shavings ◽  
Chicken Litter ◽  
The Impact

In South Africa, the need for water treatment is increasing, especially in the mining sector. As active water treatment technologies are expensive, the mining sector has an increasing need for passive water treatment technology, with low maintenance and operating costs, yet efficient water treatment ability. Literature on passive water treatment suggests that these systems only offer a narrow range of treatment capabilities. Therefore, hybrid water treatment systems could be a solution to low-cost water treatment in South Africa. The degrading packed bed reactor (DPBR) is one of the units comprising the hybrid treatment group. The DPBR’s main action is to convert sulfates into sulfides and alkalinity, since this reduces the impact on the environment by increasing the pH and reducing the salinity. In this study, 6 small-scale DPBRs were constructed. Each was classified according to its unique organic source (manure, straw, vegetable food processing waste, wood shavings, chicken litter and a combined sample with layers of all the carbon sources). Synthetic acid mine drainage (AMD) was fed through the 6 bioreactors for a period of 3 months. Permeabilities, leachate samples and effective void volumes were measured from the DPBRs. From the experiments conducted, it was found that the manure and combination bioreactors (with equal layers of manure, straw, compost, wood shavings and chicken litter) had the lowest overall permeabilities, with straw and compost having the highest permeabilities. Linked to this, the experiments showed that the manure and combination bioreactors had the largest decreases in effective porosity with straw and compost having the least. Hydraulically, the combination bioreactor performed the best by incorporating the best attributes from each carbon source. Wood shavings preformed almost as well. Chicken litter clogged within 18 days after the initiation of the experiment and thus was the least effective substrate.

scholarly journals The effect of saw dust in a flocculent with bentonite clay and FeSO4 in AMD treatment without addition of a neutralizer

2019 ◽  
Vol 14 (3) ◽  
pp. 633-644 ◽  
Author(s):  
I. O. Ntwampe
Keyword(s):  
Reduction Potential ◽  
Mine Drainage ◽  
Bentonite Clay ◽  
Similar Treatment ◽  
Saw Dust ◽  
Jar Test ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Removal Efficiencies ◽  
Synthetic Acid

Abstract 200 mL of synthetic acid mine drainage (AMD) was poured into five 500 mL glass beakers and treated in a jar test. The samples were dosed with 1.0–2.5 g bentonite clay, 20–60 mL of 0.025 or 0.05 M FeSO4 and 1.0–2.5 g saw dust respectively. The samples were mixed at 250 rpm for 2 minutes and reduced to 100 rpm for 10 minutes. The samples were allowed to settle for 1 hour, after which the pH, oxidation-reduction potential (ORP) and turbidity were measured (exp. A). Two other similar sets of experiments were conducted by dosing the samples with a combination of bentonite clay and FeSO4 with and without saw dust, similar treatment and measurements (exp. B and exp. C), similar treatment and measurements were conducted. The pH and the efficiencies of the flocculants containing 0.025 and 0.05 M Fe3+ in FeSO4 are similarly identical. The removal of turbid materials from the samples with FeSO4 is the lowest, followed by a combination of bentonite clay and FeSO4, whereas a combination of bentonite clay, FeSO4 and saw dust the highest. Comparative removal efficiencies between the two flocculants show that the presence of FeSO4 is relatively insignificant. The removal efficiency of a combination of bentonite clay, FeSO4 and saw dust from AMD sample is low with for Cu2+, and optimal for both Ni2+ and Fe2+ ions.

scholarly journals The efficiency of a flocculent consisting of saw dust and bentonite clay in the removal of Fe and Ni from AMD

2020 ◽  
Vol 15 (1) ◽  
pp. 188-200
Author(s):  
I. O. Ntwampe ◽  
R. Mthembu
Keyword(s):  
Crystal Morphology ◽  
Mine Drainage ◽  
Bentonite Clay ◽  
High Sorption Capacity ◽  
Saw Dust ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Removal Of Heavy Metals ◽  
High Sorption ◽  
Synthetic Acid

Abstract Sets of experiments were conducted by pouring 200 mL of synthetic acid mine drainage (AMD) into five 500 mL glass beakers, dosed with varying quantities of bentonite clay and saw dust interchangeably, mixed at 250 and 100 rpm for 2 and 10 mns respectively. The samples settled for 1 hour after which the pH, concentration, oxidation reduction potential (ORP) and percentage removal of heavy metals were measured. The results show that the removal efficiency of a flocculent on Ni and Fe is effective. The results show that saw dust does not affect the conductivity of a solution. The ORP of the samples with a flocculent with increasing bentonite clay exhibits a higher rate oxidation than that of a flocculent with increasing saw dust. The crystal morphology of the SEM micrographs with 1.5 g bentonite clay and 1.5 g saw dust show three types of structures, i.e. round flocs, elongated and clustered agglomerates which is indicative of high sorption capacity.

Hydrogeological Properties of Gypseous soils in South Africa

2019 ◽  
Vol 122 (3) ◽  
pp. 389-396
Author(s):  
M. Greyling ◽  
J.L. Van Rooy
Keyword(s):  
South Africa ◽  
Particle Size ◽  
Hydraulic Conductivity ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Small Scale ◽  
Prepared Sample ◽  
Brine Sample ◽  
Gypsum Content ◽  
Hydrogeological Properties

Abstract Gypseous soils occur in the western arid and semi-arid regions of South Africa and Namibia. These soils exhibit a complex nature and abnormal behaviour due to their gypsum content and as such they have become more prevalent in research. As these soils are finding more use in industry, an astute understanding of their hydrogeological properties and behaviour is required. Powdery gypseous soil samples collected from the Northern Cape (Geelvloer) and Western Cape (Rooiberg and R355) Provinces, as well as a prepared sample, are subject to XRD analysis, particle size distribution determination and falling-head permeability tests using both water and brine. The testing served as preliminary research to guide further studies into the topic. The prepared sample, with 19% fines, comprises 35% gypsum and 65% sand. Geelvloer samples, with 91.95% gypsum content, are comprised mostly of sand-sized particles with 45% fines. Rooiberg samples contain 75% fines with a slightly lower gypsum content of 83.25%, while R355 samples have 50% fines with 75.35% gypsum. It is generally understood that particle size distribution contributes to the hydraulic conductivity of soils, where a higher portion fines will result in a lower conductivity. In the case of gypseous soils, the solubility is of importance as well, as it may have long term effects. With the intent of evaluating the effect of the aforementioned factors on the hydraulic conductivity of gypseous soils in South Africa, the samples taken represent differences in particle size distribution and origin. Geelvloer had k-values in the order of 8.82×10-6 m/s, with the brine sample giving 9.43×10-6 m/s, while the k-values for Rooiberg and R355 were in the order of 3.90×10-6 m/s and 5.87×10-6 m/s, respectively. The brine resulted in 5.63×10-6 m/s for Rooiberg and 9.90×10-6 m/s for the R355 sample. The made sample, having less fines, had k values in the order of 2.15×10-5 m/s, and 4.19×10-5 m/s for the brine. The differences between the results are largely negligible and show that despite what is believed to influence the hydraulic conductivity, in the case of gypseous soils in South Africa, on a small scale, it remained unaffected.

Exploring the South African Government Communication on Land Expropriation without Compensation

2020 ◽  
Vol 72 (1-3) ◽  
Author(s):  
Lungisani Moyo
Keyword(s):  
South Africa ◽  
Food Security ◽  
South African ◽  
Small Scale ◽  
South African Government ◽  
Eastern Cape ◽  
The South ◽  
Land Expropriation ◽  
African Government ◽  
Government Communication

ABSTRACT This paper used qualitative methodology to explore the South African government communication and land expropriation without compensation and its effects on food security using Alice town located in the Eastern Cape Province South Africa as its case study. This was done to allow the participants to give their perceptions on the role of government communication on land expropriation without compensation and its effects on South African food security. In this paper, a total population of 30 comprising of 26 small scale farmers in rural Alice and 4 employees from the Department of Agriculture (Alice), Eastern Cape, South Africa were interviewed to get their perception and views on government communications and land expropriation without compensation and its effects on South African food security. The findings of this paper revealed that the agricultural sector plays a vital role in the South African economy hence there is a great need to speed up transformation in the sector.

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