Fungal based SBR: a Model Investigation in an Open Culture on the removal of glucose and on the effect of toxic compounds on the biomass

An investigation was performed to explore the capabilities of a filamentous fungus – Trichoderma viride, strain 8/90 - to aseptically grow in a glucose-fed Sequencing Batch Reactor system in extreme environmental conditions (pH 3.5). Microscopic investigations were carried out to assess fungal dominance in the open culture. Batch tests were carried out to characterize the ability of the biomass to resist to toxic shocks, in which gallic acid was dosed. The fungus showed a significant ability to grow and to remove all the organic load at the adopted feeding rate (2000 mgGlucose/l/d), attaining high biomass yields. Furthermore, it showed to be able to resist to concentrated (1 g L-1) gallic acid even though the biomass had not been exposed to it before. Further, the microbial biomass (about 2.5 gVSS L-1) was able to completely remove gallic acid in aerobic conditions in a timeframe of 12 h

Mass transfer impacts in flocculent and granular biomass from SBR systems

An experimental study was conducted to describe mass transfer impacts within nitrifying aggregates sourced from sequencing batch reactor (SBR) activated sludge systems. Flocculent and granular sludge with high nitrification activity was obtained in two laboratory SBR systems, supplied with a synthetic, ammonium-based feed. The flocculent biomass was fractionated using a sieving procedure, in order to, obtain biomass fractions with different particle size distributions. The oxygen uptake rate (OUR) response to changes in dissolved oxygen concentration was measured under highly controlled conditions in a titrimetric and off-gas analysis (TOGA) sensor, and the results used to assess mass transfer effects. As the average particle size of the biomass increased, mass transfer limitations were found to increase significantly. Empirically fitted, apparent K-S,K-O2 values were demonstrated to be highly dependent on particle size, and reflect the mass transfer limitations occurring in the aggregates within a given system. Such parameters thus have little to do with the actual biokinetic parameter from which they are derived. The results obtained from the TOGA sensor study were consistent with those obtained from a microelectrode study on the same nitrifying granules. Together, these studies add considerable weight to the conclusion that consideration of external and internal mass transfer limitations is vital to the accurate description of activated sludge treatment processes, particularly those with a high oxygen uptake rate

In-house asset management in the Australian superannuation industry

We examine how executives from the Australian superannuation industry perceive and approach the choice between managing assets in-house, versus outsourcing to external investment managers. We find that decision frameworks, as well as the perceived benefits and challenges of in-house management, can be described in terms of four elements: costs, capabilities, alignment and governance. Industry participants address these four elements in diverse ways. This is reflected in a variety of decision approaches, aspects that are considered and emphasised in decision-making, and implementation structures

PREVALENCE OF VEROCYTOTOXIGENIC ESCHERICHIA-COLI SEROTYPE O157H7 IN CHILDREN WITH DIARRHEA ATTENDING A SYDNEY HOSPITAL

Verotoxin producing Escherichia coli, in particular serotype O157:H7, have been implicated as an important cause of acute gastroenteritis in children. This study was undertaken to determine if E.coli O157:H7 is an important cause of acute gastroenteritis in children in metropolitan Sydney. During the period from October 1990 to September 1991, stools from patients presenting with acute diarrhoea to The Children's Hospital, Camperdown, were examined for the presence of common bacterial pathogens. In addition, stools were grown on sorbitol McConkey agar and sorbitol non-fermenting organisms were serotyped with O157 antiserum by slide agglutination. The isolates were then tested with H7 antisera and investigated for the production of verocytotoxin and other pathogenic markers including plasmid-associated EHEC adhesin and chromosomally encoded attachment-effacement gene. Only two strains (isolated from two different patients, 0.1% of specimens tested) were agglutinated by O157 antiserum and both were non-motile (H-). However, both strains produced verotoxin and expressed other virulence markers, suggesting that they were responsible for the diarrhoea. Both patients experienced mild, self limited gastroenteritis. We conclude that E. coli O157:H7 is an uncommon cause of acute gastroenteritis in Sydney children presenting to a children's hospital

ABC of Thatcherism 1979-1989

1.95Available from British Library Document Supply Centre- DSC:89/23621(ABC) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Nitrogen fixation in the treatment of pulp and paper wastewaters

Pulp and paper wastewaters are generally low in the key nutrient, nitrogen. Nitrogen supplementation is often practised to ensure effective BOD removal. Maintaining consistently low effluent discharge concentrations of nitrogen from nitrogen supplemented biological treatment systems is very difficult. Matching nitrogen addition rates to load variations is effective, but requires accurate flow and organic load measurements. By manipulating treatment conditions to select for the growth of nitrogen fixing microorganisms, it is possible to achieve good BOD removals without the addition of nitrogen. As the organisms only fix the nitrogen required for growth, very low soluble nitrogen discharge concentrations are possible. This concept has been explored in the development of a new technology for the treatment of nitrogen deficient wastewaters