Traditionally, Membrane Bioreactor (MBR) Validation is focussed on performance during commissioning when membranes are new, and the range of operating conditions are limited. As membranes age it is important to understand how MBR performance changes to have confidence in the quality of the water produced. Gathering data on the relationships between operational monitoring parameters such as turbidity and pathogen removal during the life of membranes would assist operators to understand the ongoing performance of membranes compared with initial performance.

The former Water Recycling Centre of Excellence developed the MBR Validation Protocol. This protocol was prepared as part of NatVal to provide guidance for the validation of MBRs. It proposed a tiered approach that allowed for a simplified process where log reduction values (LRVs) are claimed.

The aim of this project is to collect and review performance data from a broad range of operating MBR facilities in Australia to understand the pathogen LRV performance in relation to operating conditions and monitoring parameters; targeting a range of membrane age, integrity, performance, and control. This will allow water managers to understand and predict the ongoing performance of MBR plants compared to initial performance, informing future MBR design and also assisting in optimising membrane lifecycle planning. This research will also provide operators and regulators with greater confidence MBR operation throughout the asset life, and lower the whole of life cost of MBR ownership for water service providers by maximising the validated operating envelope.

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.

The Australian Guidelines for Water Recycling (AGWR) require water recycling treatment processes to be validated in ways that ensure that recycled water does not pose a risk to health, safety or the environment. Stage I of this project developed a National Validation Framework (WaterRA project 3009). This Stage II develops and describes detailed protocols that utilities can apply to implement the validation framework and achieve compliance with the AGWR.

The Australian Guidelines for Water Recycling (AGWR) encompass acceptable health, safety and environmental targets for different types of recycled water. This research begins development of a series of processes that utilities can apply to achieve compliance with the AGWR. This Stage 1 of the project describes six systems for recycling water (natural, managed aquifer recharge, membrane treatment, chemical and photooxidation, biological and adsorptive treatments); six aspects of recycling validation systems which included regulator, utility and technology provider perspectives in different States and jurisdictions, as well as micropollutant risk assessment, instrumentation performance and knowledge transfer, training and capacity building. Current and emerging techniques for scheme validation, and relevant guidelines and case studies were reviewed, and knowledge gaps and core issues were identified. Altogether these were used to develop a ‘National Validation Framework’ and were the basis of a plan for completing Stage 2 (WaterRA project 3018).

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.

Harmful pathogens and compounds must be removed from wastewater before it can be discharged to the environment or used for irrigation, and many source waters need salts removed to make them potable. Microfiltration and ultrafiltration membranes remove pathogens and unwanted chemicals but as they are used, they become fouled and blocked by particulates and compounds from the water being filtered, as well as by the formation of biofilm, and by chemical interactions between solutes and the membrane materials. Although the membranes are cleaned regularly, the cleaning chemicals themselves can cause a problem. This research characterised the damage that various cleaning regimens inflict on membranes made of different materials and examined the effects of progressive and consecutive stages of membrane aging and degradation on performance. It was concluded that the type of cleaning agent affects the mechanism of membrane degradation and the severity of membrane integrity loss. More information is needed regarding the cleaning protocols and agents used in industry. Information from this research can inform a generally applicable model to predict membrane aging and decline in performance.

The Australian water industry uses a variety of membrane processes to remove unwanted pathogens or compounds, such as salt, from source waters. As membranes age their ability to fulfil these removal and filtering functions declines. The problem is that although there are recognised and validated tests for membrane integrity, they are usually performed only on new membranes, and information about the effect of membrane aging on pathogen removal is limited. This project reviewed published literature and identified four methods suitable for future development as Membrane Integrity Tests that may prove applicable to evaluate aging membranes during ongoing and long-term plant operation.

In Australia, remote and regional communities frequently manage relatively small, isolated water treatment and waste management systems which have water quality and health risks characteristic of small-scale decentralised operations. Australian water utilities have a wealth of experience in addressing these issues, and this project gathered and documented a series of case studies from Victoria, Tasmania and the Northern Territory to form a knowledge base that can be referred to in the future.

Although water utilities recognise the value of online instruments that provide real-time monitoring capability, there are problems with visualising and interpreting datasets, and with distinguishing between data resulting from real-world changes in treatment plant operating conditions, for example changed turbidity or flow, and instrument failure. There are also challenges around instrument installation and operation. This project developed tools to support data visualisation and interpretation by building a prototype visualisation platform for analysing complex online UV spectral data in conjunction with weather and lab data (see Factsheet 2 ‘Development of an online platform’). To improve differentiation between instrument failure and real-world data a Bayesian Belief Network model was developed to analyse patterns and variations within datasets. Real operational, high turbidity data was used to demonstrate that this model could accurately identify different causes for the readings which included filter ripening, backwash and other causes (see Factsheet 3 ‘Improving decision making in water plant operability through Bayesian Belief networks’). Strategies for instrument installation and operation were illustrated through case studies.