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Wastewater management will be refined
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Winemakers are seeking guidance that will help establish wastewater treatment systems that are appropriate for specific sites and operational circumstances.
They also want a reduction in the running costs for treating wastewater.
These are two of the most important issues arising from a CSIRO national survey and regional consultation workshops which followed.
The survey, supported by Grape and Wine Research and Development Corporation funding, was another step in a program to take leadership in environmental responsibility. It follows a report on the Impact of Winery Wastewater on Ecosystem Health by researchers Anu Kumar and Rai Kookana, which found considerable variability in methods of treating and re-using water.
An explanation of these variations, including correlations with winery practices and scale of operations, was sought by the survey. While it provided a clearer picture of the industry, additional data will be accumulated during a second stage of auditing.
Such work will assist in the development of the improved guidelines and management tools sought by winemakers.
Already there are some widely applied principles, including minimising water use, segregation of different strength waste streams, practices that reduce the amount of cleaning agent used in washing equipment, and choice of cleaning chemicals with low sodium levels.
During industry consultation it became evident, however, that although winemakers respect compliance requirements they want the “real focus” to be on the environmental impact. This means that while applying the general principles there must be a framework that includes assessment based on good science for each set of circumstances.
As one industry participant at a regional workshop said “Technologies are available and are improving but we want to know what is ‘practical, affordable and workable for this site’. As the potential impact will be affected by operations and re-use options, there shouldn’t be a ‘one size fits all’ regulatory regime. Attention has to be directed to what the effects may be in a certain location, which brings in the importance of what to measure and how to measure it.”
On the matter of affordability, some industry personnel place a figure of $2,000 on each megalitre of treated wastewater while others say their figure is much higher and in the range of $5,000 — $8,000 per megalitre.
With regard to the question of “what to measure and how to measure it” Anu Kumar says this aspect will be refined through research. The results will be of interest to wine companies and regulatory authorities alike because decisions will be able to be made on a foundation of more comprehensive information.
Aquatic disposal is no longer allowed. So it follows that in addition to defining what matters when land-based systems are planned, land disposal quality criteria need to be re-assessed. For example, Biochemical Oxygen Demand (BOD) is a test used to measure the concentration of biodegradable organic matter present in a sample of water. It was selected in 1908 as the definitive test for organic pollution of rivers. With land-based use of treated water (whether this is for irrigation of vines, woodlots, grazing pastures, dates or other crops), critical measurements of salt appear to be more important than BOD.
The project team believes it is necessary to establish best practices for different soil types and crops from soil chemical, physical and biological perspectives. This would then allow better matching of treatment methods with the chosen disposal system.