project description goes here

Real time monitoring and process control is a crucial component of optimal, pro-active water and wastewater management but there is a lack of information about real-world experience, operation, return on investment and the costs that are related to online monitoring. This research collated information from literature reviews, case studies, industry surveys and interviews, and concluded that more than 250 manufacturers sell over 100 water quality applications. In this context it is important to carefully define operational needs and the availability of skills, resources and budget before choosing an application. It is also important to manage and set realistic expectations and to embed online monitoring within the organisation.

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.

Membranes are used to remove viruses from treated wastewater to make it safe for discharge or recycling. It is important to monitor the integrity of membranes and check that viruses cannot break through. This creates a need for surrogates that are cheaper, safer and easier to use than the non-hazardous indicator virus currently applied to test membrane integrity. This research synthesised a series of fluorescent nanoparticles with similar dimensions to viruses, with the idea that the fluorescence would support continuous in situ monitoring in real time, but unfortunately the nanoparticles did not emit enough fluorescence and could not be detected in the product water.

Ultrafiltration membranes are used to remove viruses from treated wastewater. This makes it safe for release to the environment or for recycling, but it is important to monitor integrity of the membrane to ensure there are no damaged sections that viruses can break through. This research demonstrated that a silver nanoparticle is a valid, safer alternative to using non-infectious bacteriophage viruses that are currently used to test membrane integrity. The silver nanoparticle was tested and validated in a laboratory-scale ultrafiltration membrane unit. It was concluded that work should proceed to full-scale validation and integrity-testing of ultrafiltration membranes in recycled water applications.

Reverse osmosis (RO) is used to desalinate seawater and brackish groundwater, and to remove microscopic pathogens from treated wastewater. The salty water is pressurised on one side of the RO membrane and this is part of the process that results in water molecules passing (diffusing) through the membrane to the lower pressure solution on the other side. Salts such as sodium chloride (table salt) and calcium sulphate and calcium carbonate (scale) do not diffuse easily across the RO membrane and build up on the high-pressure side. Eventually scale deposition on the membrane prevents the diffusion of water molecules and the production of freshwater declines. This research tested four commercial and three in-house antiscalent chemicals, and additionally developed a technique to monitor scale formation and RO membrane performance in real-time. It was concluded that the antiscalent ‘PC-191T’ was best and that adding an ‘Electrical Impedance Spectroscope’ to RO systems has the potential to deliver a sensitive in-situ, real-time monitoring method capable of detecting very early scale formation, well before membrane performance declines. This will enable optimisation of membrane scale removal and improve the efficiency of freshwater production.

Sewage is delivered to wastewater treatment plants (WWTPs) where benign microbial organisms within ‘activated sludge’ vessels contribute to the removal of harmful pathogens from the sewage. The activity and pathogen-removing ability of these helpful organisms is affected by many factors including temperature, numbers of fine particles, pH, ammonia, and the time available to remove the pathogens. Regulatory authorities require at least 90% (one log removal value, LRV) of the pathogens to be removed, but as WWTP operating conditions vary, the LRVs change. This problem led to recognition of the need to develop models capable of predicting relationships between plant operating parameters (such as temperature) and pathogen removal. This research reviewed published reports and datasets, then set up and ran an experimental activated sludge pilot plant to generate data about a range of operating conditions and pathogen removals. These datasets were used to develop models which had only a ‘poor’ predictive value for clostridia but were ‘good’ for giardia and ‘very good to excellent’ for the removal of other pathogens. These models need to be extended with more operating conditions but have the potential to be used to attribute LRVs and for future integration into online real-time monitoring.

Disinfection is essential for removing harmful microbial pathogens and making safe drinking water but can also cause formation of disinfection by-products (DBPs), some of which pose a health risk. Thirty years of research have amassed a wealth of knowledge about the identification, formation, treatment and control, toxicology and epidemiology of DBPs in Australia. This project compiled, assessed and presented an overview of DBP-related research in Australia.

A survey of water utilities identified the top five challenges faced in daily operations, and technical, economic and literature reviews identified remote sensing strategies and technologies to address these five operational issues. The need for, and benefits of real-time monitoring which facilitates cost-effective and efficient responses to rapidly changing conditions, were common to all five challenges, which were: monitoring cyanobacteria and their metabolites, the effects of contamination and extreme climate-change driven events on water quality, the variation in climatological data over relatively small distances (need to increase focus, precision and produce ‘finer’ datasets for reservoir management), asset inspection and management and monitoring catchments for a variety of factors. This research evaluated and explained the solutions, strengths, weaknesses, and costs of products best suited for addressing each challenge.

The management of blue-green algae (cyanobacteria), and the toxins and taste and odour compounds they produce, have been the focus of more than 30 years of research, but there is still a need for a suite of user-friendly tools to assess and manage aesthetic and toxin risks. This project conducted an extensive literature review about the ability of six treatment paradigms to remove MIB, geosmin, saxitoxins, microcystins and cylindrospermopsin. An empirical spreadsheet-base model was then built and used to simulate ‘whole-of-plant’ removal of cells and toxic metabolites. This model performed well when tested with two years of full-scale sampling data.