Water Journal : Water Journal February 2013
48 Feature Article WATER FEBRUARY 2013 GWF now provides an innovative, sustainable and economically responsible reclaimed water solution, transforming the region's approach to municipal and industrial wastewater disposal, enhancing natural catchments, increasing riverine ows to the Gippsland Lakes, and improving the region's water supply security. GWF has drastically improved the treated ef uent quality discharged to the ROS, while simultaneously achieving an 11--15ML/d water reuse bene t for industry and fodder crop irrigation, with similar water resource extraction reductions. GWF is the rst project in Australia to incorporate water recycling into its design from inception, and features an innovative combination of technologies to produce puri ed water of better quality than that produced at many drinking water plants. It was commissioned in stages and became operational in late 2010, achieving stable operations in early 2011. Its treatment processes rely on biological treatment, membrane ltration and reverse osmosis (RO) to transform nearly 35 megalitres per day (ML/d) of wastewater into a sustainable resource. Wastewater ows comprise 16ML/d of municipal wastewater and 19ML/d of industrial (pulp and paper) wastewater. The municipal and industrial wastewater streams use separate treatment trains customised to their speci c source water quality. This enables GWF to economically produce 8--10ML/d of high-quality puri ed water for industrial reuse at Australian Paper's Maryvale mill. As a result, the same amount of fresh water (almost 3 billion litres a year) is freed up in the region's rivers and reservoirs, enough to supply an Australian town of about 40,000 people. Other streams are reused for agriculture, with the balance available for resale when suitable customer demand is established. RECLAIMED WATER USES GWF's recycled water product is highly puri ed water produced from the Gippsland's municipal sewage supply. This high-quality water is now used by Gippsland Water's largest industrial customer, Australian Paper, the Southern Hemisphere's largest pulp and paper manufacturer. The water is delivered into the paper mill's water supply system, reducing demand on its existing raw water supply. In addition, other municipal wastewater streams were recon gured to enable an additional 4--5ML/d of recycled water for irrigation on Gippsland Water's 8,000-ha farm at Dutson Downs. During the GWF design, the paper mill's employees were consulted about their concerns and water requirements, with great care taken to ensure they continued to deliver premium quality product to their customers. RECLAIMED WATER QUALITY AND TECHNICAL INNOVATION By using advanced ltration techniques such as membrane bioreactors (MBRs) and RO, GWF's advanced treatment system produces puri ed recycled water of better quality than that produced at many drinking water plants around the globe. In addition, the plant meets stringent nutrient standards for its reuse product: total nitrogen concentrations of less than 2 milligrams per litre (mg/L) and total phosphate concentrations of less than 0.1 mg/L as P. Signi cant challenges to achieving this high-quality reuse water included: • Highly variable municipal ows, which are severely impacted by wet weather ow peaks; • Continual need to balance municipal processing capacity against industrial capacity demands; • Signi cant industrial treatment train complexities, including: » High variability of industrial wastewater (quality and ow); some parameters vary daily by a factor of 10 » Occasional high non-biodegradable organics and sulfur loads (typical for Kraft wastewaters), requiring tertiary treatment to remove strongly coloured refractory dissolved organic carbon » High degradable carbon loads, but very low nutrient content » Sporadic toxic load spikes » Aerobic biomass with strong tendency to slimy bulked sludge (non-settleable and dif cult to lter). To ensure premium-quality recycled water for use in any part of the paper mill, GWF was designed with: • Separate treatment of municipal and industrial liquid process trains, with common support facilities to optimise operations. This is a key feature because it segregates higher salinity and strongly Gippsland Water Factory (GWF) produces 8ML/d of puri ed water for industrial reuse at Australian Paper's Maryvale mill, and is also GWF's main industrial waste customer.
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