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in Brisbane, Melbourne, and Adelaide, the recycled water being delivered in separately identified "purple pipes" and available for toilet flushing, car washing, garden watering, etc. Ensuring there were no cross connections between the two systems was essential and required disciplined inspections. Many high-rise office buildings and apartment buildings include wastewater recycling plants for redistribution of recycled water for reuse within the building. This contributed to such buildings achieving high "Green Star" environmental accreditation, thereby being able to secure higher rents to offset the additional capital cost of fitting the buildings with dual reticulation. The Melbourne City Council, Sydney Water, Melbourne Water, and the South Australian Water Corporation were among leaders with new buildings that were both energy- and water-efficient. Recycled water has also been returned to rivers to add to environmental flows, offsetting water removed upstream. Managed aquifer recharge began to be introduced for the storage of recycled water until needed, responding to the minimal winter/peak summer demand for irrigation water for public parks and amenities. Some systems used reverse osmosis (RO) and advanced oxidation processes (AOP), while others used ultrafiltration (UF). An interesting example was the UF system installed in Adelaide's Glenelg Wastewater Treatment plant, the recycled water being piped to Adelaide Airport and also the Parklands, which surround Adelaide's Central Business District. Municipal Investment In 2004, a Water Smart Australia program was announced. This provided for investment in the conservation and more effective utilization of water resources. "Diversity of supply" through the provision of alternative water sources became the new driver. The Federal government contributed financially to recycling and desalination initiatives to "accelerate the development and uptake of smart technologies and practices in water use across Australia." Within two years, 48 percent of the investment had been directed towards water recycling projects. Some projects were developed in "near emergency conditions." Ultimately, the program ran until June 2012, supporting 78 projects with total costs of AUD$5 billion, $1.5 billion of which came from the Federal government. Following the unprecedented water restrictions having been introduced in all mainland capital cities, seawater desalination plants were urgently developed for Perth (2), Sydney, Adelaide, Queensland's Gold Coast, and Melbourne. These plants, with a total annual capacity of 530 gigaliters (GL) — roughly 120 billion gallons (BG) — involved a variety of design, funding, and technical development methods, but all were fundamentally dependent on RO. The Queensland government developed Advanced Water Recycling Plants adjacent to Brisbane Waste Water Treatment Plants at Bundamba, Luggage Point, and Gibson Island, with a capacity of 84 GL (19 BG) per year. The scheme, known as the Western Corridor Scheme, was based on the manufacture (as it was described) of purified recycled water by microfiltration (MF), RO, and AOP. The recycled water was to be pumped as "indirect potable" to the Wivenhoe Dam. A portion of the flow was to be used for cooling at two power stations which were then using 10 percent of Brisbane's daily drinking water consumption. Brisbane's water resources were linked together with the Gold Coast desalination plant to form a water grid. The whole project was completed urgently within two years and involved constructing 208 km (129 miles) of pipelines. Lessons Learned Unfortunately, most of these projects came to fruition as the drought came to an end with localized but widespread flooding in 2010. The Wivenhoe dam filled to 200 percent of water storage capacity as the "head space" served as a flood control dam. Hence, the Western Corridor Scheme has never been used for its intended purpose of supplementing Brisbane's water wateronline.com n Water Innovations 17 WATERREUSE Figure 1. Adelaide, capital city of South Australia, was established in 1836 with a unique set of parklands around what is now the central business district. The dry Mediterranean climate meant the parklands were dry and brown in summer, and for many years were burned off annually. Recycled water from the Glenelg wastewater treatment plant is now reticulated throughout the parklands for irrigating sporting fields and gardens. (Credit: South Australian Water Corporation) Figure 2. The Glenelg Wastewater Treatment Plant generates recycled water with these ultrafiltration modules followed by advanced oxidation (UV and chlorination) with the consequent saline stream piped to the much larger Bolivar plant for further treatment.