In an earlier project stormwater was collected from an urban environment, treated through electrolysis, injected into and retrieved from an aquifer, and reused for greywater irrigation. This research used the previously established hardware and software for ten months to gather data about operational efficacy, reliability and costs. E. coli, a common indicator of faecal contamination, was barely removed by electrolysis, and other pathogens were not examined, which prevents assessment of water quality or its compliance with the AGWR. 20878 kL stormwater were treated and added to the aquifer, and 5886 kL retrieved for irrigation. Total operational costs were $29344 and the cost of processed water ranged from $0.13 to $0.28 per kL. The purpose-designed software and computerised telemetry was reliable and suitable for upgrading with security features. It was concluded that the system has potential for further development as an alternative to using mains potable water to irrigate open public spaces.

The steam produced by boiling a kettle of salty water can be collected, condensed and drunk. Membrane distillation is an analogous process to this, but in this study the salty feedwater forms a salt-free vapour at a lower temperature; 30 – 40°C. The warm feedwater and vapour are pumped past a thin, porous membrane which repels liquid water but allows vapour to pass through the pores into a cold stream of freshwater on the other side. The vapour condenses and increases the volume of fresh, salt-free water. In this project an operational pilot plant was built and installed at an electricity generating station which produces waste heat and a stream of salty effluent that is normally discarded. The pilot plant was equipped with a 0.67m2 membrane, ran continuously for 3 months, and produced an average of 2.2L freshwater per hour. This equates to 3.4L/h/m2. The membrane area can be scaled up to increase production. It was concluded that this is a viable treatment technology for industrial wastewater that emits minimal greenhouse gasses.

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.