Gold coast seaway smartrelease decision support system: optimising recycled water release in a sub tropical estuarine environment.

Gold Coast Water is responsible for the management of the water, recycled water and wastewater assets of the City of the Gold Coast on Australia's east coast. Excess treated recycled water is released at the Gold Coast Seaway, a man-made channel connecting the Broadwater Estuary with the Pacific Ocean, on an outgoing tide in order for the recycled water to be dispersed before the tide changes and re-enters the Broadwater estuary. Rapid population growth has placed increasing demands on the city's recycled water release system and an investigation of the capacity of the Broadwater to assimilate a greater volume of recycled water over a longer release period was undertaken in 2007. As an outcome, Gold Coast Water was granted an extension of the existing release licence from 10.5 hours per day to 13.3 hours per day from the Coombabah wastewater treatment plant (WWTP). The Seaway SmartRelease Project has been designed to optimise the release of the recycled water from the Coombabah WWTP in order to minimise the impact to the receiving estuarine water quality and maximise the cost efficiency of pumping. In order achieve this; an optimisation study that involves intensive hydrodynamic and water quality monitoring, numerical modelling and a web-based decision support system is underway. An intensive monitoring campaign provided information on water levels, currents, winds, waves, nutrients and bacterial levels within the Broadwater. This data was then used to calibrate and verify numerical models using the MIKE by DHI suite of software. The Decision Support System will then collect continually measured data such as water levels, interact with the WWTP SCADA system, run the numerical models and provide the optimal time window to release the required amount of recycled water from the WWTP within the licence specifications.

The use of microorganisms with broad range substrate utilisation for the ferricyanide-mediated rapid determination of biochemical oxygen demand.

The feasibility of replacing oxygen with a synthetic electron acceptor in microbial catabolism was investigated as a rapid method for the determination of biochemical oxygen demand (BOD). Microorganisms known for their broad range organic substrate utilisation were investigated. It was shown that Trichosporon cutaneum, Pseudomonas putida and Bacillus licheniformis could utilize the ferricyanide ion as an alternative electron acceptor, in place of oxygen, for the catabolic oxidation of a range of simple organic compounds. The biochemical reactions were monitored by measuring the amount of microbially produced ferrocyanide using amperometry at a Pt disk microelectrode. Catabolic degradation efficiencies approaching those of the conventional 5-day assay were achieved in 1 h. BOD(5) equivalent values for a range of simple organic solutions were determined for each of the microorganisms. The effect of increased incubation time and the choice of appropriate calibration standards for rapid BOD assays were also considered.

A guide to comprehensive tendering for sterile dressing packs.

Local circumstances dictated that the supply of sterile dressing packs for the District be the subject of competitive tendering in August, 1984. This article shares the experience of conducting this task which involved developing a methodology in advance of detailed DHSS or Regional guidelines on this service.