Water Journal : Water Journal February 2013
WATER FEBRUARY 2013 50 Feature Article Gippsland Water placed a self-imposed greenhouse gas emissions constraint on the project, which for estimating purposes established a $10 per ton carbon cost/value incentive upon the Alliance's commercial participants. This drove signi cant energy and carbon ef ciency innovation -- six years before the carbon tax recently implemented by the Australian Government. The incentives target was to reduce greenhouse gas emissions by 20 per cent off a theoretical benchmark of 52,000 tons CO2 per year. Based on current data, GWF's greenhouse gas emissions generate 32,000 tons of carbon dioxide equivalent (CO2-e) per year, representing a 38 per cent reduction on the benchmark concept design estimate. GWF also resulted in a 100 per cent reduction in fugitive methane releases from the ROS, as the gas is now captured during the treatment process and used for bene cial reuse electricity generation at the GWF. The decision to focus on "carbon-ef cient design" has resulted in additional savings to Gippsland Water. The $23 per ton carbon tax now in force has been avoided because the greenhouse gas emission reductions attained by the project have placed its total direct (i.e., onsite) emissions below the taxable emission threshold. This equates to about $900,000 in carbon tax savings every year, as originally estimated. These savings do not include the much larger value saved by avoided purchases of chemicals and electricity savings totaling around several million dollars a year. To further optimise its management of materials, water and energy, sludge from the municipal treatment train is digested in the anaerobic reactors, reducing the volume of sludge that must be managed, and providing a nutrient source to support biological treatment of the industrial stream. Biosolids produced by the facility are incorporated into Gippsland Water's Soil Organic Recycling Facility, where it is converted into a high-grade fertiliser. AUTOMATED OPERATIONS GWF has multiple treatment processes distributed over a compact site. The control system provides fully automated facility operations from any plant location, and monitors and records critical operating requirements for compliance reports. Pi Process Book by OsiSoft and an Advanced Computation Engine (ACE) mathematics module, which calculates in real time a wide range of treatment performance and chemical processing parameters, are used by operators and management. Automated data broadcasts keep support specialists around the world up to date on plant trends and status. To allow the continued improvement of operating performance the computer control system includes online trends, including a real-time carbon emission footprint tracking system that allows operators to use live trends of actual greenhouse gas emissions to further optimise the process. PROCESS VALIDATION GWF uses Rhodamine WT (R-WT) uorescent dye testing to validate its RO system's virus removal. Developed by CH2M HILL for membrane ltration system integrity testing, R-WT was adopted by the Victorian Department of Health for validating RO pathogen removal and incorporated by the American Society for Testing of Materials into their Standard Practice for Integrity Testing of Water Filtration Membrane Systems. R-WT, as a surrogate for all pathogens of concern, especially viruses, provides an inexpensive, easy-to-apply method for quantifying RO system pathogen removal up to 4-log, both prior to initial operation and periodically throughout operation. R-WT enables Gippsland Water to better assess how well the RO system is performing, improves regulatory reporting, and enhances its ability to produce the highest quality reclaimed water by ensuring optimal pathogen removal -- well beyond what can be achieved using conventional surrogates like conductivity or total dissolved solids (TDS). R-WT is an excellent tool that can be used by other water recycling plants to validate their RO systems. GWF also has online dissolved organic carbon (DOC) instrumentation that constantly validates DOC removal log ratio across the RO process. EMERGENCY AND CRISIS MANAGEMENT Following the disastrous 2009 bush res in Victoria, Gippsland Water upgraded its emergency and crisis management capability with a t-for-purpose incident room to provide personnel with a high- quality coordination and communications facility. The facility has proven very effective in helping to manage emergency situations to date and provides a modern training facility, which has seen multi-agency use since its completion. GWF also maintains a comprehensive internal safety system, including a wide range of automated safety controls and alarms. Due to the toxic nature of the biogas produced at GWF by the unique anaerobic pretreatment system, a robust biogas management system has also been implemented with multiple layers of redundancy (backup) systems. PUBLIC AND PRIVATE SECTOR ALLIANCE The GWF Alliance, comprised of principal sponsor Gippsland Water and a consortium of CH2M HILL, Trans eld Services and Parsons Brinckerhoff, designed, constructed and commissioned GWF, with environmental The regional outfall sewer, which was previously a major source of unpleasant odour in Central Gippsland.
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