Stephens M.L.,South Australian Water Corporation |
Lambert M.F.,University of Adelaide |
Simpson A.R.,University of Adelaide
Journal of Hydraulic Engineering | Year: 2013
The application of inverse transient analysis (ITA) to estimate the location and magnitude of lost lining and internal corrosion of metal pipelines is demonstrated for a field pipeline. The method uses a transient model and inverse search algorithm to analyze patterns of measured pressure reflections obtained after a transient pressure wave is induced in a pipeline. The method is applied in the field on a 6 km long section of a 750 mm nominal diameter steel pipeline with internal cement mortar lining. The equipment used for generating hydraulic transients and measuring pressure responses in the pipeline is described. Results of the field tests are analyzed to estimate the location and extent of internal wall damage along the pipeline. Extensive ultrasonic thickness survey results are used to corroborate the approximate location and magnitude of predicted pipeline wall damage. © 2013 American Society of Civil Engineers.
Ho L.,South Australian Water Corporation |
Ho L.,University of Adelaide |
Sawade E.,South Australian Water Corporation |
Newcombe G.,South Australian Water Corporation
Water Research | Year: 2012
The treatment of cyanobacterial metabolites can consume many resources for water authorities which can be problematic especially with the recent shift away from chemical- and energy-intensive processes towards carbon and climate neutrality. In recent times, there has been a renaissance in biological treatment, in particular, biological filtration processes, for cyanobacteria metabolite removal. This in part, is due to the advances in molecular microbiology which has assisted in further understanding the biodegradation processes of specific cyanobacteria metabolites. However, there is currently no concise portfolio which captures all the pertinent information for the biological treatment of a range of cyanobacterial metabolites. This review encapsulates all the relevant information to date in one document and provides insights into how biological treatment options can be implemented in treatment plants for optimum cyanobacterial metabolite removal. © 2011 Elsevier Ltd.
Yang R.,Murdoch University |
Paparini A.,Murdoch University |
Monis P.,South Australian Water Corporation |
Ryan U.,Murdoch University
International Journal for Parasitology | Year: 2014
Clinical microbiology laboratories rely on quantitative PCR for its speed, sensitivity, specificity and ease-of-use. However, quantitative PCR quantitation requires the use of a standard curve or normalisation to reference genes. Droplet digital PCR provides absolute quantitation without the need for calibration curves. A comparison between droplet digital PCR and quantitative PCR-based analyses was conducted for the enteric parasite Cryptosporidium, which is an important cause of gastritis in both humans and animals. Two loci were analysed (18S rRNA and actin) using a range of Cryptosporidium DNA templates, including recombinant plasmids, purified haemocytometer-counted oocysts, commercial flow cytometry-counted oocysts and faecal DNA samples from sheep, cattle and humans. Each method was evaluated for linearity, precision, limit of detection and cost. Across the same range of detection, both methods showed a high degree of linearity and positive correlation for standards (R2≥0.999) and faecal samples (R2≥0.9750). The precision of droplet digital PCR, as measured by mean Relative Standard Deviation (RSD;%), was consistently better compared with quantitative PCR, particularly for the 18S rRNA locus, but was poorer as DNA concentration decreased. The quantitative detection of quantitative PCR was unaffected by DNA concentration, but droplet digital PCR quantitative PCR was less affected by the presence of inhibitors, compared with quantitative PCR. For most templates analysed including Cryptosporidium-positive faecal DNA, the template copy numbers, as determined by droplet digital PCR, were consistently lower than by quantitative PCR. However, the quantitations obtained by quantitative PCR are dependent on the accuracy of the standard curve and when the quantitative PCR data were corrected for pipetting and DNA losses (as determined by droplet digital PCR), then the sensitivity of both methods was comparable. A cost analysis based on 96 samples revealed that the overall cost (consumables and labour) of droplet digital PCR was two times higher than quantitative PCR. Using droplet digital PCR to precisely quantify standard dilutions used for high-throughput and cost-effective amplifications by quantitative PCR would be one way to combine the advantages of the two technologies. © 2014 Australian Society for Parasitology Inc.
Koh W.,Murdoch University |
Clode P.L.,University of Western Australia |
Monis P.,South Australian Water Corporation |
Thompson R.A.,Murdoch University
Parasites and Vectors | Year: 2013
Background: In natural aquatic environments biofilms are known to act as environmental reservoirs for Cryptosporidium parvum oocysts. However, the fate of these oocysts within biofilms has yet to be determined. Methods. This study aimed to identify if biofilms have the ability to support the multiplication of Cryptosporidium by measuring the change in parasite number over time using quantitative polymerase chain reaction (qPCR) and detecting the possible extracellular developmental stages using a combination of confocal microscopy and immunolabelling techniques. Pseudomonas aeruginosa biofilm flow cell systems were established and C. parvum oocysts were constantly supplied over a six day period. Results: A significant (P < 0.001) increase in Cryptosporidium was detected as the biofilm matured, with the total number of C. parvum multiplying 2-3 fold during this period. With this, various Cryptosporidium developmental stages (sporozoites, trophozoites, type I and II meronts) were identified from the biofilm. Conclusion: This is the first study demonstrating that biofilms not only serve as an environmental reservoir for oocysts, but are also capable of supporting the multiplication of Cryptosporidium over time in an aquatic environment. © 2013Koh et al.; licensee BioMed Central Ltd.
Majewski P.,University of South Australia |
Keegan A.,South Australian Water Corporation
Applied Surface Science | Year: 2012
This study's focus was on the water-based, one-pot preparation and characterisation of silica particles coated with 3-(2-aminoethyl) aminopropyltrimethoxysilane (Diamo) and the efficiency of the material in removing the pathogens Escherichia coli, Pseudomonas aeruginosa, Mycobacterium immunogenum, Vibrio cholerae, poliovirus, and Cryptosporidium parvum. The water-based processing resulted in Diamo coated silica particles with significantly increased positive surface charge as determined by zeta potential measurements. In addition, X-ray photoelectron spectrometry of pure and Diamo coated silica confirmed the presence of Diamo on the surface of the particles. Thermogravimetric measurements and chemical analysis of the silica indicated a surface concentration of amine groups of about 1 mmol/g silica. Water treatment tests with the pathogens showed that a dose of about 10 g appeared to be sufficient to remove pathogens from pure water samples which were spiked with pathogen concentrations between about 10 2 and 10 4 cfu/mL. © 2011 Elsevier B.V. All rights reserved.
Krampe J.,South Australian Water Corporation
Water Science and Technology | Year: 2013
Optimising the energy consumption and energy generation of wastewater treatment plants (WWTPs) is a topic with increasing importance for water utilities in times of rising energy costs and pressures to reduce greenhouse gas (GHG) emissions. Assessing the energy efficiency and energy optimisation of a WWTP are difficult tasks as most plants vary greatly in size, process layout and other influencing factors. To overcome these limits it is necessary to compare energy efficiency with a statistically relevant base to identify shortfalls and optimisation potential. Such energy benchmarks have been successfully developed and used in central Europe over the last two decades. This paper demonstrates how the latest available energy benchmarks from Germany have been applied to 24 WWTPs in South Australia. It shows how energy benchmarking can be used to identify shortfalls in current performance, prioritise detailed energy assessments and help inform decisions on capital investment. © IWA Publishing 2013.
Krampe J.,South Australian Water Corporation
Water Science and Technology | Year: 2013
In this paper a method to determine the cycle time for sequencing batch membrane bioreactors (SBMBRs) is introduced. One of the advantages of SBMBRs is the simplicity of adapting them to varying wastewater composition. The benefit of this flexibility can only be fully utilised if the cycle times are optimised for the specific inlet load conditions. This requires either proactive and ongoing operator adjustment or active predictive instrument-based control. Determination of the cycle times for conventional sequencing batch reactor (SBR) plants is usually based on experience. Due to the higher mixed liquor suspended solids concentrations in SBMBRs and the limited experience with their application, a new approach to calculate the cycle time had to be developed. Based on results from a semi-technical pilot plant, the paper presents an approach for calculating the cycle time in relation to the influent concentration according to the Activated Sludge Model No. 1 and the German HSG (Hochschulgruppe) Approach. The approach presented in this paper considers the increased solid contents in the reactor and the resultant shortened reaction times. This allows for an exact calculation of the nitrification and denitrification cycles with a tolerance of only a few minutes. Ultimately the same approach can be used for a predictive control strategy and for conventional SBR plants. © IWA Publishing 2013.
Whiley H.,Flinders University |
Keegan A.,South Australian Water Corporation |
Fallowfield H.,Flinders University |
Ross K.,Flinders University
Frontiers in Microbiology | Year: 2014
Legionella is an opportunistic pathogen of public health concern. Current regulatory and management guidelines for the control of this organism are informed by risk assessments. However, there are many unanswered questions and uncertainties regarding Legionella epidemiology, strain infectivity, infectious dose and detection methods. This review follows the EnHealth Risk Assessment Framework, to examine the current information available regarding Legionella risk and discuss the uncertainties and assumptions. This review can be used as a tool for understanding the uncertainties associated with Legionella risk assessment. It also serves to highlight the areas of Legionella research that require future focus. Improvement of these uncertainties will provide information to enhance risk management practises for Legionella, potentially improving public health protection and reducing the economic costs by streamlining current management practises. © 2014 Whiley, Keegan, Fallowfield and Ross.
Drikas M.,South Australian Water Corporation |
Dixon M.,South Australian Water Corporation |
Morran J.,South Australian Water Corporation
Water Research | Year: 2011
Removal of natural organic matter (NOM) is a key requirement to improve drinking water quality. This study compared the removal of NOM with, and without, the patented magnetic ion exchange process for removal of dissolved organic carbon (MIEX DOC) as a pre-treatment to microfiltration or conventional coagulation treatment over a 2 year period. A range of techniques were used to characterise the NOM of the raw and treated waters. MIEX pre-treatment produced water with lower concentration of dissolved organic carbon (DOC) and lower specific UV absorbance (SUVA). The processes incorporating MIEX also produced more consistent water quality and were less affected by changes in the concentration and character of the raw water DOC. The very hydrophobic acid fraction (VHA) was the dominant NOM component in the raw water and was best removed by MIEX pre-treatment, regardless of the raw water VHA concentration. MIEX pre-treatment also produced water with lower weight average apparent molecular weight (AMW) and with the greatest reduction in complexity and range of NOM. A strong correlation was found between the VHA content and weight average AMW confirming that the VHA fraction was a major component of the NOM for both the raw water and treated waters. © 2010 Elsevier Ltd.
Somaratne N.,South Australian Water Corporation
Environmental Earth Sciences | Year: 2015
There is unanimity in the literature that chloride mass flux crossing the piezometric surface requires a steady-state for the saturated or unsaturated version of the conventional chloride mass balance (CMB) method to apply. Data indicate that chloride concentration in point recharge fluxes crossing the piezometric surface can remain at or near surface runoff chloride concentrations, rather than finding equilibrium with groundwater chloride. Preferential groundwater flows were observed through an interconnected network of highly permeable zones with groundwater mixing along flow paths. Measurements of salinity and chloride indicated that fresher water pockets exist at point recharge locations. A stable and measurable fresh water plume develops only when a large quantity of surface water enters the aquifer as a point recharge. In such circumstances, assumptions and boundary conditions of the conventional CMB method are not met, and the method requires modification to include both point and diffuse recharge mechanisms. This paper describes a generalised CMB that is applicable to groundwater basins with point recharge. In three case studies, point recharge flux is estimated to contribute 63, 85, and 98 % of total recharge. However, long-term average annual point recharge volumes are much smaller than the aquifer storage, at 1.5, 1.95, and 0.75 % and distributed across the basins at discrete locations. In the study basins, conventional CMB-estimated recharges are 46, 20, and 11 % of the recharge estimated using the generalised CMB, indicating the importance of accommodating point recharge into the CMB method. The generalised CMB method provides an alternative long-term net recharge estimation method for groundwater basins characterised by both point and diffuse recharge. © 2015, Springer-Verlag Berlin Heidelberg.