Water Journal : Water Journal September 2012-1
water recycling refereed paper technical features 90 SEPTEMBER 2012 water recently conducted on recycled water schemes, in accordance with the AGWR- approved hazard identification and assessment methodology. Based on the classification criteria listed in the AGWR, no 'high' risks were identified. Some of the risks classified as 'moderate' included excessive, unauthorised or inappropriate use of recycled water, slime growth within recycled water reticulation system and recycled water pipe breakage. These risks are currently being managed as part of the Recycled Water Quality Improvement Management Plan (RWQIMP), which would systematically decrease the exposure to risk for Hunter Water and its recycled water customers. The risk assessments will be reviewed again once a statistically valid set of data becomes available through monitoring undertaken as part of Recycled Water Quality Monitoring Plans. Future Recycled Water Opportunities Hunter Water aims to pursue sustainable water recycling opportunities as a substitute for potable water and as a way of managing effluent discharges from WWTPs, where financially and environmentally feasible. A number of studies including the Lower Hunter Recycled Water Initiative (LHRWI) are currently underway to identify recycled water opportunities in the lower Hunter, both for effluent management and for water security. The LHRWI would deliver significant recycled water projects to improve the water supply security in the Lower Hunter. The completion of the LHRWI is projected to save 3,730ML of potable water annually, which is expected to result in the volume of recycled water in the Lower Hunter almost doubling to 8,700ML per annum or 15% of total effluent treated in 2011--12. This is further expected to result in a reduction of 22,000kg of nitrogen and 8,000kg of phosphorus being discharged to Hunter River each year. Figure 2 shows the locations of future recycled water opportunities. These opportunities include: • Branxton Irrigation Water Scheme Branxton Irrigation Water Scheme will provide up to 300ML of unrestricted recycled water to The Vintage for golf course and general landscape irrigation. It will also include upgraded delivery infrastructure and better quality recycled water for the Branxton Golf Course and adjacent farm. The construction of this scheme is now complete. It is due to be commissioned by September 2012. • Kooragang Industrial Water Scheme The Kooragang Industrial Water Scheme (KIWS) will provide highly treated process water to commercial and industrial users on Kooragang Island and is expected to save approximately 3,300ML of potable water annually. The KIWS, once completed, will be the largest water-recycling scheme in the Lower Hunter region, providing significant drinking water savings while reducing discharges to Hunter River. Recycled water for the scheme will be sourced from Shortland WWTP, where it will receive secondary treatment before being pumped to an advanced recycled water treatment plant located at the Steel River industrial estate. The advanced treatment process is expected to consist of microfiltration, chlorine disinfection and reverse osmosis to produce high quality process water. Process water will then be pumped from Steel River to storage reservoirs on Kooragang Island. Process water will be suitable for a wide range of industrial applications including use in boilers, cooling towers, chemical mixing, fire fighting and general wash-down. In addition to the LHRWI, Hunter Water is also considering the following recycled water opportunities: • Chisholm Dual Reticulation Scheme The Chisholm Dual Reticulation Scheme (CDRS) is proposed to provide highly treated recycled water to approximately 5,000 homes (over 20 years) for toilet flushing, garden Figure 3. Site plan of the Karuah Effluent Reuse Enterprise (ERE).
Water Journal November 2012-1
Water Journal August 2012