Application of bacterial bioflocculants for wastewater and river water treatment.

Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2008.Dyes are often recalcitrant organic molecules that produce a colour change and contribute to the organic load and toxicity of textile industrial wastewater. Untreated effluent from such sources is harmful to aquatic life in the rivers and lakes due to reduced light penetration and the presence of highly toxic metal complex dyes. The use of alum as flocculant/coagulant in wastewater treatment is not encouraged as it induces Alzheimer’s disease in humans and results in the production of large amounts of sludge. Therefore, the development of safe and biodegradable flocculating agents that will minimize environmental and health risks may be considered as an important issue in wastewater treatment. Bioflocculants are extracellular polymers synthesized by living cells. In this study, bacterial bioflocculants were assessed for their ability to remove dyes from textile wastewater as well as reducing the microbial load in untreated river water. The bacteria were isolated from a wastewater treatment plant and identified using standard biochemical tests as well as the analysis of their 16S rDNA gene sequences. Six bacterial isolates were identified viz. Staphylococcus aureus, Pseudomonas plecoglossicida, Pseudomonas pseudoalcaligenes, Exiguobacterium acetylicum, Bacillus subtilis, and Klebsiella terrigena. The flocculating activities of the bioflocculants produced by these isolates were characterized. The effect of temperature, pH, cations and bioflocculant concentration on the removal of dyes, kaolin clay and microbial load was also determined. The amount of bioflocculants produced by the bacterial isolates ranged between 5 and 27.66 g/l. According to the findings of the present study, bacterial bioflocculants were composed of carbohydrates, proteins, uronic acid, and hexosamine in varying quantities. The bioflocculants were effective to varying degrees in removing the dyes in aqueous solution, in particular whale dye, medi-blue, fawn dye and mixed dyes, with a decolourization efficiency ranging between 20-99.9%. Decolourization efficiency was influenced by the bioflocculant concentration, pH, temperature, and cations. The bacterial bioflocculants were also capable of reducing both the kaolin clay and the microbial load from river water. The flocculating activity ranged between 2.395–3.709 OD-1 while up to 70.84% of kaolin clay and 99% of the microbial load from the river water was removed. The efficiency of kaolin clay flocculation increased with higher concentration of bacterial bioflocculants. The optimum pH for the flocculating activity was observed between 6 and 9. The best flocculating activity was observed at 28oC. Divalent cations such as Mg2+ and Mn2+ improved the flocculation while salts such as K2HPO4, CH2COONa, and Na2CO3 did not. The findings of this study strongly suggest that microbial bioflocculants could provide a promising alternative to replace or supplement the physical and chemical treatment processes of river water and textile industry effluent

A critical evaluation of local level responses to mine closure in the Northwestern KwaZulu-Natal coal belt region, South Africa

The de-industrialisation process that was a common feature of North America and Western Europe in the 1970s, through into the 1980s has become an observable feature in African countries and South Africa in particular in the last two decades. Globally, hard hit areas include those associated with the early Industrial Revolution characterised by mass production and the agglomeration of iron and steel, coal and textile industries. General changes in the global market, especially the falling demand for extractive heavy minerals like coal and gold have also affected many countries region and localities. In the case of South Mrica, the previous high economic dependence on mined minerals like coal and gold has resulted in many once prosperous mining regions of the country being reduced to a shadow of their former selves. The worst affected areas in South Africa are those of the Klerksdorp Goldfields in the North West Province and Free State Goldfields, with the latter alone losing 100,000 jobs during the 1990s. This trend has also been acute in the coal-mining industry of the KwaZulu-Natal province since the late 1970s. The firms that had grown in the shadow of the major mining company supplyipg machinery, or who processed the semi-manufactured product are also severely affected by the closing down and restructuring in the mining and iron industries. These industries have often been forced to close down because of a break in the vital connections they developed with these mining industries. Such localised economic crisis has encouraged the universal trend towards the devolution of developmental responsibilities to the local governments and other local stakeholders to - empower them to respond to these changes. This study investigated the local economic initiatives which have been undertaken in the three municipalities of north-western KwaZulu Natal i.e. Utrecht, Dundee and Dannhauser to respond to the closures which have taken place in the mining industry of this region, which used to be among the most prosperous coal mining regions of South Africa. Using their new developmental mandate the local governments, in partnership with the communities and other external interveners have tried to respond to these localised economic crisis and also indirectly to the general poverty and underdevelopment, which characterises this region of KwaZulu-Natal. The effects of apartheid policies, and previous discriminatory rural development policies in, particular, and the Regional Industrial Development policy, which was intensively applied in the 1980s by the pre-1994 government regime, have further compounded the magnitude of the challenge. The lack of capacity in some municipalities has constrained successful implementation of Local Economic Development has led to some communities acting alone to face their situation with or without external intervention

If not now, when? Time for the European Union to define a global health strategy

Speakman, E. M., McKee, M., & Coker, R. (2017). If not now, when? Time for the European Union to define a global health strategy. Lancet Global Health, 5(4), e392-e393. https://doi.org/10.1016/S2214-109X%2817%2930085-

Textile Dye Removal from Wastewater Effluents Using Bioflocculants Produced by Indigenous Bacterial Isolates

Bioflocculant-producing bacteria were isolated from activated sludge of a wastewater treatment plant located in Durban, South Africa, and identified using standard biochemical tests as well as the analysis of their 16S rRNA gene sequences. The bioflocculants produced by these organisms were ethanol precipitated, purified using 2% (w/v) cetylpyridinium chloride solution and evaluated for removal of wastewater dyes under different pH, temperature and nutritional conditions. Bioflocculants from these indigenous bacteria were very effective for decolourizing the different dyes tested in this study, with a removal rate of up to 97.04%. The decolourization efficiency was largely influenced by the type of dye, pH, temperature, and flocculant concentration. A pH of 7 was found to be optimum for the removal of both whale and mediblue dyes, while the optimum pH for fawn and mixed dye removal was found to be between 9 and 10. Optimum temperature for whale and mediblue dye removal was 35 °C, and that for fawn and mixed dye varied between 40–45 °C and 35–40 °C, respectively. These bacterial bioflocculants may provide an economical and cleaner alternative to replace or supplement present treatment processes for the removal of dyes from wastewater effluents, since they are biodegradable and easily sustainable

Article Textile Dye Removal from Wastewater Effluents Using Bioflocculants Produced by Indigenous Bacterial Isolates

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The closure of coal mines and local development responses in Coal-Rim Cluster, northern KwaZulu-Natal, South Africa

The impact of mine closure can have a devastating effect on the local economies of the towns that they once supported. Drawing on comparative, international material, this article examines the nature and effectiveness of the local economic development responses that have been initiated in the former coal-mining towns in northern KwaZulu-Natal in South Africa. Although a range of innovative locally identified strategies have been embarked upon, considerably greater effort and investment will be needed in order to catalyse significant and meaningful regeneration endeavours.