Water Journal : Water Journal August 2011
water AUGUST 2011 61 governance marked with a lilac water drop send recycled water product(s) for off-site uses. The number and variety of schemes with different product qualities make them complex to manage. This became particularly evident when, in consultation with NSW Health, Sydney Water began to implement the Australian Guidelines for Water Recycling Phase 1 2006 (2006 AGWR). Preparing Recycled Water Quality Management Plans (RWQMPs) initially highlighted that although most management procedures were common across all schemes, there were also many individual aspects for schemes. Sydney Water manages its recycled water schemes under the same ISO-certified quality management systems (9001 and 14001) that it uses throughout its business. Sydney Water manages risk across all of its business under a policy and procedures based on AS4360:2004 and its replacement AS/NZS.ISO 31000:2009 (Risk Management -- Principles and Guidelines on Implementation). Reference will be made to it as ISO31000:2009 for the remainder of this paper. Sydney Water's risk management procedures are included under its ISO-certified QMS. Although Sydney Water has operated irrigation schemes since 1967 and has always practised on-site recycling at its WWTPs, water recycling has substantially increased during the drought of the last decade. This includes an increase in the end uses, complexity and cost of schemes. With most cost-effective recycling initiatives already delivered, Sydney Water's focus is now shifting towards ongoing operation and maintenance rather than development of new schemes. In addition, Sydney Water and NSW Health agreed to move to the 2006 AGWR for managing health risks in recycling schemes. This has resulted in further development and modification of business processes to manage risks in recycled water. At the same time, Sydney Water has seen a shift in understanding about water, recycling and especially in its treatment operations. Most recycling schemes have been built onto existing WWTPs. Traditionally, WWTP operation has focussed on discharge requirements and environmental protection. However, as plants have taken on supplying recycled water product, our understanding of plants has changed to one of seeing them as production facilities manufacturing a range of products, of which recycled water is one product line. Figure 2 illustrates this for a generic type of plant and, as noted in a previous paper (Landers and Blayney, 2009), one example of this is Sydney Water's Wollongong facility. The graphical representation in Figure 2 understands WWTPs more from the perspective of resource recovery. Consistent with this thinking, Sydney Water has renamed all of its WWTPs that supply recycled water product(s) to off-site customers as Water Recycling Plants (WRPs). Figure 2: Conceptual treatment plant overview. The shift in thinking in Sydney Water has been partially mirrored in the public sphere, with increased awareness of water as a resource. This conceptual presentation does not include other elements of the supply chain such as equipment supply, knowledge and skills, nor does it include potential nutrient recovery. In addition, while not shown here, financial sustainability is an essential element of this paradigm, as noted by Davis (2010). Risk in Recycled Water -- Background Discussion Section 2.2.4 of the 2006 AGWR discusses the mechanism for assessing risk, which aligns with ISO31000:2009. The guidelines apply this specifically to managing human health and environmental risks associated with recycled water schemes. However, in providing recycled water there are other business risks such as financial, legal and reputational. While this paper follows the same focus as the AGWR, Sydney Water addresses all aspects of technical and business risks when considering a recycled water scheme. The risk assessment mechanism of the AGWR and ISO31000:2009 provides, for a given scheme, a static snapshot of: • Hazards -- and events that give rise to these hazards; • The causes of the hazards and hazardous events; • Consequences and their likelihoods; • The range of control measures (risk mitigations) either in place or available for use; • The unmitigated risk and the residual risk, or, in the case of a proposed scheme, the target risk; • A gap analysis between the desired and actual risk states, as well as possible options for addressing these gaps. The AGWR provide several indications on the sources of risk, differences between human health and environmental risks, and estimation of risk levels including quantification and uncertainty. The guidelines also note that risk is dynamic and advise that: "The hazard identification and risk assessment should be reviewed and updated periodically, because changing conditions may introduce important new hazards or modify risks associated with identified hazards." (AGWR, 2006, p39). Figure 1: Existing and committed recycled water schemes.
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