B.E. (University of Adelaide)
Location: Room A210 Engineering North Annex
Phone: + 61 8 8303 3093
FAX: + 61 8 8303 4373
Dr David Lewis, Associate Professor Brian O'Neill, School of Chemical Engineering
Mike Holmes, United Water International
Optimising the DAFF Process (Dissolved Air Flotation-Filtration)
Following a commitment from the South Australian Water Corporation to an Environmental Improvement Program, a reuse scheme was initiated to divert a portion of the treated effluent from Bolivar WWTP to the agricultural belt north of Adelaide via the Virginia Pipeline Scheme. In order to facilitate this, a dissolved air flotation and filtration plant was installed to treat 150ML/day of effluent from the waste stabilisation ponds (WSPs) to a level suitable for agricultural reuse. Waste stabilisation pond effluent typically contains high levels of algal matter, with the algae often removed by sequential coagulation and flocculation followed by DAFF treatment. Elevated levels of algae present a variety of operational problems for DAFF treatment, including: turbidity breakthrough, additional and inefficient chemical dosing, shorter filter run times, increased filter headloss and more frequent backwashing. Given the variability in the numeration and speciation of algae in the WSP effluent,it has proven difficult to develop an optimal chemical dosing strategy for algae removal via the DAFF process and thereby guarantee reuse water quality. A methodology has been developed whereby pure algal cultures are cultivated, concentrated and reconstituted into WSP effluent to simulate an algal bloom. Preliminary studies have provided limited results, yet show the methodology of spiking algae into suspension provides a sound basis for further optimisation studies. This process may then be extended to investigation of a controlled heterogeneous mixture. Ultimately, the aim is to develop a comprehensive tool which will allow plant operators to more easily optimise plant performance.
- Water and wastewater treatment,
- Biochemical engineering and biotechnology,
- Environmental engineering
- Amos, S.A., van Heeswijck, T., Lewis, D.M., "Influence of coagulant dose and pH on surface charge of Microcystis - implications for coagulation" Chemeca 2005, Smart Solutions - Doing More with Less" 25-28 September 2005, Brisbane Queensland.
- Amos, S.A., Lewis, D.M., Sweeney, D.G., Kaeding, U.W., "Optimisation of chemical dosing for microalgae removal via DAFF treatment" Chemeca 2005, Smart Solutions - Doing More with Less 25-28 September 2005, Brisbane Queensland.