Water SA 

About: Water SA is an academic journal published by Water Research Commission. The journal publishes majorly in the area(s): Water quality & Water resources. It has an ISSN identifier of 0378-4738. It is also open access. Over the lifetime, 2339 publications have been published receiving 51990 citations. The journal is also known as: Water S A & Water S.A..

Adsorption kinetics for the removal of chromium (VI) from aqueous solutions on the activated carbons prepared from agricultural wastes

Abstract: The batch removal of Cr(VI) from aqueous solution using low-cost adsorbents such as cornelian cherry, apricot stone and almond shell under different experimental conditions was investigated in this study. The influences of initial Cr(VI) ion concentration (20 to 300 mg·l-1), pH (1 to 4) and particle size (0.63 to 1.60 mm) have been reported. Adsorption of Cr(VI) is highly pH-dependent and the results indicate that the optimum pH for the removal was found to be 1 for all types of carbon. A comparison of kinetic models applied to the adsorption of Cr(VI) ions on the adsorbents was evaluated for the pseudo first-order, the pseudo second-order, Elovich and intraparticle diffusion kinetic models, respectively. Results show that the pseudo second-order kinetic model was found to correlate the experimental data well.

A review of hyperspectral remote sensing and its application in vegetation and water resource studies

Abstract: Multispectral imagery has been used as the data source for water and land observational remote sensing from airborne and satellite systems since the early 1960s. Over the past two decades, advances in sensor technology have made it possible for the collection of several hundred spectral bands. This is commonly referred to as hyperspectral imagery. This review details the differences between multispectral and hyperspectral data; spatial and spectral resolutions and focuses on the application of hyperspectral imagery in water resource studies and, in particular the classification and mapping of land uses and vegetation.

Microbial decolourisation of a reactive azo dye under anaerobic conditions

Abstract: Water-soluble azo dyes are used extensively in the textile industry and are known to be problematic with respect to from textile waste waters. Under anaerobic conditions azo dyes can be utilised as terminal electron acceptors in microbial respiration, and are reduced and decolourised concurrently with re-oxidation of reduced flavin nucleotides. The microbial decolourisation of an azo dye (C.I. Reactive Red 141) was investigated with respect to the kinetic order of azo reduction and rate-controlling factors of the reaction. Decolourisation of C.I. Reactive Red 141 was found to be first order with respect to dye concentration, although increasing the initial dye concentration in the serum bottles resulted in decreasing k values of − 0.441/h (100 mg/(of C.I. Reactive Red 141), − 0.316/h (150 mg/l) and − 0.25:/h (200 mp/l). The presence of labile carbon in the anaerobic system was found to be essential in order to obtain an acceptable rate of decolourisation. The k value obtained for decolourisation of the azo dye without a supplemental carbon source (glucose) was − 0.012/h, in comparison to a k value of − 0.441/h when supplemented with glucose (1 g/l). The presence of nitrate in the anaerobic system was found to inhibit decolourisation, while the presence of sulphate was found to have to discernible effect on the rate of decolourisation. A low redox potential (− 450 to − 500 mV) was found to be conducive to rapid decolourisation of C.I. Reactive Red 141. A C.I. Reactive Red 141 depradation product was positively identified as 2-aminonaphthalene-1,5-disulphonic acid, confirming that azo reduction was responsible for decolourisation of the azo dye. A toxicity assay was performed which showed that C.I. Reactive Red 141 was inhibitory to the anaerobic microbial community at concentrations >100 mg/l, but that prior exposure of the biomass to the dye increased the resistance to previously inhibitory dye concentrations

Adsorption of cu (ii) and cr (vi) ions by chitosan: kinetics and equilibrium studies

Abstract: The ability of chitosan as an adsorbent for Cu (II) and Cr (VI) ions in aqueous solution was studied. The experiments were don e as batch processes. Equilibrium studies were done on both cross-linked and non-cross-linked chitosan for both metals. Cr (VI) adsorption behaviour could be described using the Langmuir isotherm over the whole concentration range of 10 to 1000 mg· l -1 Cr. The maximum adsorption capacity for both types of chitosan was found to be 78 mg·g -1 for the non-cross-linked chitosan and 50 mg·g -1 for the cross-linked chitosan for the Cr (VI) removal. For the Cu (II) removal the Freundlich isotherm described the experimental data over the whole concentration range of 10 to 1000 mg·l-1 Cu (II). The maximum adsorption capacity for both types of chitosan can be estimated to be greater than 80 mg·g -1 . Cr (VI) removal was the highest at pH 5 but pH did not have a large influence on Cu (II). From these results it is clear that the adsorption of heavy metals is possible with chitosan, but that with this m ethod, end concentrations of below 1 mg·l-1 can hardly be obtained.

Flood damage estimation - A review of urban stage-damage curves and loss functions

Abstract: The estimation of damages is integral to the formulation of flood policy. For the assessment of flood losses this requires the use of stage? amage curves for di~fere~t classes of buildings. A review is presented ofthe methods used to construct these. The use of synthetic techniques IS stresse~ and attentton glv~n to actual and potential losses and to the susceptibillty of buildings to failure in response to floodwater depth and velocity. Recommendatlom, are presented for the construction and use of stage-damage curves for residential and commercial buildings in South Africa.