Treatability of SA surface waters by activated carbon

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Treatability of South African surface waters by enhanced coagulation

Abstract: The majority of South African inland surface water sources are compromised due to a long-standing national policy of mandatory return flows. With renewed emphasis on the removal of organic carbon in the latest SANS 241 water quality standard, many South African water treatment managers may need to consider adoption of enhanced coagulation (EC) in the near future to achieve both turbidity and NOM removal. From the study of 4 South African inland waters, this paper demonstrates that UV254 absorbance provides a more accessible, reliable and rapid way of monitoring NOM at treatment plant level. This report also provides a detailed procedure for determining the dosages for EC in terms of UV254 absorbance at jar test level. Using ferric chloride as coagulant, a correlation was established to estimate the coagulant dosage for any desired level of UV254 absorbance removal. This correlation enables a preliminary assessment of EC as a means of planned NOM removal. Should EC promise to be a candidate process for NOM removal, it should be verified at jar test level using the proposed procedure

Natural organic matter in drinking water sources: its characterisation and treatability

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Place branding of seaports in the Middle East

This paper analyses seaports’ brand personalities as a means of understanding similarities and differences of these important locations and their relationship with their host place image. Drawing upon Aaker’s (J Mark Res 34:347–356, 1997) brand personality construct, the study presents lexical analysis from the websites of nine seaports in the Middle East. Each seaport’s website is content analysed, and the brand personality is measured using Aaker’s (1997) framework and Opoku’s (Licentiate Thesis, Lulea University of Technology, ISSN, 1402-1757, 2005) dictionary of synonyms. Findings show that seaports have developed a level of isomorphism upon particular dimensions of brand image; however, the findings also show the most distinctive seaports were linking their seaport to their place brand. In particular, the findings show only the Port of Jebel Ali has a clear and distinctive brand personality and to a lesser extent the Ports of Sohar, Shahid Rajee and Khor Fakkan. The research has important management implications of branding for public diplomacy and demonstrates seaport brand positioning in relation to place branding, used to inform public communication and marketing

Diversities, affinities and diasporas: a southern lens and methodology for understanding multilingualisms

We frame multilingualisms through a growing interest in a linguistics and sociology of the ‘south’ and acknowledge earlier contributions of linguists in Africa, the Américas and Asia who have engaged with human mobility, linguistic contact and consequential ecologies that alter over time and space. Recently, conversations of multilingualism have drifted in two directions. Southern conversations have become intertwined with ‘decolonial theory’, and with ‘southern’ theory, thinking and epistemologies. In these, ‘southern’ is regarded as a metaphor for marginality, coloniality and entanglements of the geopolitical north and south. Northern debates that receive traction appear to focus on recent ‘re-awakenings’ in Europe and North America that mis-remember southern experiences of linguistic diversity. We provide a contextual backdrop for articles in this issue that illustrate intelligences of multilingualisms and the linguistic citizenship of southern people. In these, southern multilingualisms are revealed as phenomena, rather than as a phenomenon defined usually in English. The intention is to suggest a third direction of mutual advantage in rethinking the social imaginary in relation to communality, entanglements and interconnectivities of both South and North

Chapitre 14: Phytopathogènes et stratégies de contrôle en aquaponie

peer reviewedAmong the diversity of plant diseases occurring in aquaponics, soil-borne pathogens, such as Fusarium spp., Phytophthora spp. and Pythium spp., are the most problematic due to their preference for humid/aquatic environment conditions. Phytophthora spp. and Pythium spp. which belong to the Oomycetes pseudo-fungi require special attention because of their mobile form of dispersion, the so-called zoospores that can move freely and actively in liquid water. In coupled aquaponics, curative methods are still limited because of the possible toxicity of pesticides and chemical agents for fish and beneficial bacteria (e.g. nitrifying bacteria of the biofilter). Furthermore, the development of biocontrol agents for aquaponic use is still at its beginning. Consequently, ways to control the initial infection and the progression of a disease are mainly based on preventive actions and water physical treatments. However, suppressive action (suppression) could happen in aquaponic environment considering recent papers and the suppressive activity already highlighted in hydroponics. In addition, aquaponic water contains organic matter that could promote establishment and growth of heterotrophic bacteria in the system or even improve plant growth and viability directly. With regards to organic hydroponics (i.e. use of organic fertilisation and organic plant media), these bacteria could act as antagonist agents or as plant defence elicitors to protect plants from diseases. In the future, research on the disease suppressive ability of the aquaponic biotope must be increased, as well as isolation, characterisation and formulation of microbial plant pathogen antagonists. Finally, a good knowledge in the rapid identification of pathogens, combined with control methods and diseases monitoring, as recommended in integrated plant pest management, is the key to an efficient control of plant diseases in aquaponics.Cos

On the Evaluation of Internal Optimizers and Correlation Functions in Kriging

Response surfaces are being used to create meta-models of expensive computer experiments (such as CFD of FEM models). The response surfaces can then be used for optimization, or for design space exploration using combinations of responses extracted from the computer experiments. The method of Kriging uses the correlation between the response values to create a best unbiased linear predictor. Normally a function, such as the Gaussian or the Exponential function, is chosen as correlation function, and its variables then fitted to the data. This is done by finding the Maximum Likelihood Estimator (MLE). Finding the MLE means a separate optimization problem, one which can be non-trivial. Several techniques to find the MLE are evaluated, namely LFOPC (a gradient-based trajectory method), Dynamic-Q (a successive quadratic approximation method) and particle swarms. This is done for different correlation functions. Responses from analytical functions and Computational Fluid Dynamic (CFD) simulations of a Submerged Entry Nozzle (SEN) used in the continuous casting of steel are used. The different optimizers are compared according to the MLE, as well as the number of times Φ was calculated to find the optimum. In this comparison the number of times the MLE was calculated for different correlation functions looked at. 2. Keywords