The role of activated sludge extracellular polymers and aerobic biomass in the removal of phosphorus from wastewater

Please read the abstract in the section 00front of this documentDissertation (MSc (Microbiology))--University of Pretoria, 2006.Microbiology and Plant Pathologyunrestricte

Predicting optimal operating points by modelling different flotation mechanisms

The inverse relationship between grade and recovery in flotation circuits is well accepted, and forms the basis of control strategies used to maxisise recovery subject to grade specifications. The concept of peak air recovery however suggests that this relationship is more complex, and that a model of this peak could indicate an optimal operating point. In this paper froth stability is modelled using a combination of fundamental and empirical models. Potential applications of a non-linear model in optimising flotation performance investigated, and the benefits demonstrated.https://www.journals.elsevier.com/ifac-papersonlinepm2020Electrical, Electronic and Computer Engineerin

Economic evaluation and design of an electric arc furnace controller based on economic objectives

Please read the abstract in the section, 00front of this documentDissertation (MEng (Electronic Engineering))--University of Pretoria, 2007.Electrical, Electronic and Computer EngineeringMEngunrestricte

The role of extracellular exopolymers in the removal of phosphorus from activated slugde

Biological phosphorus removal in activated sludge systems is thought to be a result of the action of polyphosphate accumulating organisms (PAO). However, not all phosphorus removed can be accounted for by PAO. A method for the qualitative in situ characterization of PAO cell clusters and closely associated extracellular exopolymers (EPS) is described. X-ray microanalysis was performed on samples of two activated sludge plants situated in Pretoria, South Africa. Analysis was done by means of scanning electron microscopy combined with energy dispersive spectrometry (EDS). Cell clusters with associated EPS, on average, contained between 57% and 59% phosphorus, while EPS alone contained, on average, between 27% and 30% phosphorus. Results suggest that phosphorus removal in activated sludge might be due not only to PAO, but also by EPS acting as a phosphorus reservoir

SEM-EDS for determining the phosphorus content in activated sludge EPS

Not all phosphorus removed in activated sludge systems can be accounted for by polyphosphate accumulating organisms (PAO). A method for the qualitative and quantitative in situ characterization of PAO cell clusters and closely associated extracellular polysaccharides (EPS) is described. X-ray microanalysis was performed on samples from four activated sludge plants situated in Pretoria, South Africa. Analyses were done by means of Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectrometry (EDS). Cell clusters with associated EPS on average contained between 57 and 59% phosphorus, while EPS alone contained on average between 23 and 30% phosphorus. Results suggest that phosphorus removal in activated sludge might be due not only to PAO, but also by EPS acting as a phosphorus reservoir. Extraction of EPS from two different activated sludge plants yielded different amounts of EPS, which, in combination with SEM-EDS, may shed light on different phosphate uptake abilities of different activated sludges