Algal and cyanobacterial blooms incur current treatment challenges such as high operational cost, disinfectant by-product formation, and the requirement to separate oxidants from solution after the oxidation. Advanced oxidation methods, such as cold plasma activated bubbles (CPAB), have the potential to overcome the current challenges . CPAB are bubbles containing partially or fully ionised gas that utilise the ambient condition of gas and an electric discharge to produce and deliver highly reactive oxygen and nitrogen species, such as ozone, hydrogen peroxide, hydroxyl, superoxide, and nitric oxide radicals. This project will examine methods to optimise the application of CPAB across a range of algal and cyanobacterial species to increase its technology readiness level.

PhD Thesis underway by Angelina.

Algal systems can be used to decrease the concentration of nitrogen (N) and phosphorus (P) in wastewater to low levels, and hence reduce the harm of wastewater discharge and facilitate water reuse. This research contributed to the improvements of alginate-immobilised systems for wastewater treatment and demonstrated its technical feasibility for nutrient removal from different wastewaters. The findings can be used to guide how to best implement and integrate alginate-immobilised algae into new and existing wastewater treatment plants and can form the basis for viability assessment of its commercial application.

PhD Thesis completed by Matthew Kube in December 2019.

The genus Microcystis is responsible for many ‘nuisance’ and toxic algal blooms that threaten various fresh water bodies in Australia. Of particular importance is the taxa Microcystis aeruginosa which is highly prevalent and contains a deep pangenome, leading to substantial genomic variability between strains. It has been established that certain cyanobacteria, including hepatotoxic Microcystis species, annually transition between planktonic and benthic forms. Benthic-planktonic coupling has been associated with an increase in the abundance of Microcystis during spring and summer, often resulting in dense surface blooms, followed by the sedimentation of colonies to the benthos during the cooler months. In order to improve industry predictions of the risk, timing and severity of toxic Microcystis blooms, this project aims to investigate the biological mechanisms and environmental triggers that cause bloom development. Through a range of classical isolation techniques and various ‘-omic’ studies this project will study the recruitment of benthic dwelling Microcystis species to surface waters.

PhD Thesis underway by Caitlin Romanis.

Detection of Algal and Cyanobacterial blooms have increased in lakes, rivers and reservoirs over the last two decades. This hampers drinking water treatment processes due to the high cell numbers and the release of algal organic matter that comprises toxins and taste and odour compounds. This project examined the in-depth potential of in situ fluorometers to improve early warning of bloom development via the analysis of fluorescent cell pigments to give an estimate of cell biovolume.

PhD Thesis completed by Sara Imran Khan in March 2019.

This project determined disinfection by product contribution from chlorination of algae.

Honours/PhD Thesis completed by Adam John Tomlinson in July 2018.

This project improved the knowledge of how algae species (population density, morphology and AOM concentration and character) and coagulation conditions (coagulant type, pH, polymer dose, and shear) impact algal floc properties in order to improve the C-F process and downstream separation treatment.

PhD Thesis completed by Andrea Del Pilar Gonzalez Torres in June 2018.

This project increased understanding of how cyanobacteria adapt and function in today’s environment. It provided insight to the key factors that contribute to growth of Microcystis and Anabaena in relation to physical conditions of the reservoir and reduced as well as predicted the occurrence and toxicity of blooms by understanding toxin regulation.

PhD Thesis completed by Anna Chi Ying Yeung in August 2016.

This project will use granular activated carbon to remove algal metabolites. Adsorption and biodegradation of algal metabolites will be monitored and modelled in the laboratory and at pilot scales, with the aim of guaranteeing safe and cost-effective drinking water treatment.

Raw source water contains parts of plants, blue-green algae and their toxins, and many other types of organic matter. Identifying the types and amounts of organic matter helps treatment plant operators make informed decisions about the most efficient and cost-effective methods for treating and removing unwanted substances from source waters. The problem is that many of the tests for identifying organic compounds can take hours to days to deliver results. This research developed a test that gives information immediately. It uses three commercially available fluorescent probes that each emit fluorescent light at a specific wavelength. Certain compounds within organic matter, such as proteins, “reflect” the fluorescent light, but at different wavelengths which can be detected by the probes. These patterns of “reflected” fluorescence were related to traditional tests for organic compounds. This on-line fluorescence monitoring was then trialled at real-world treatment plants. The patterns gave reliable information about broad categories of organic compounds and there was a linear correlation between dissolved organic carbon and fluorescent intensity in both raw and treated waters. This research has provided a valuable addition to the suite of tools available for producing safe, high quality drinking water.

Blue-green algae reduce water quality, especially when they produce toxins. Each algal cell can grow, reproduce all its DNA, and split into two ‘daughter’ cells, then those two ‘daughter’ cells produce four more until the numbers of algal cells bloom to extremely high numbers. High algal growth rates are associated with favourable environmental conditions (for the algae), stationary growth rates occur when the production of new cells is about the same as the number of dying cells, and if more cells die than are reproduced, the growth rate declines. The ability to predict or measure which of these three population growth rates is prevalent, and how much toxin is being produced, is information that the water industry needs to select the best methods for treating water. This project analysed the amount of DNA, and some specific sequences of DNA which correspond to the genes coding for toxins; and related the DNA analysis to actual counts of cells and measurements of toxin in water samples. This allowed the development of an improved and more informative technique for forecasting and monitoring toxic blue-green algae blooms.