WWW fit for purpose

What are some common sources of WWW?

• cleaning of tanks

• hosing down of floors and equipment

• rinsing of transfer lines

• barrel washing

• spent wine and product losses

• bottling facilities

• lab WW

• stormwater diverted into or captured in the WW management system

What are the main requirements for WWW to be considered fit for use in vineyard irrigation?

• acceptable pH, EC and cation balance

• should not exceed thresholds for Na, K and toxic ions

• biochemical oxygen demand levels must be managed to avoid odour and groundwater issues

• must be tailored to soil type, crop requirements and irrigation cycles

How does WWW irrigation affect soil chemistry and structure?

• increases Na and K in soil - can disrupt soil structure

• leads to soil dispersion, reduced infiltration and clogging

• can alter soil chemistry and increase leaching of salts and dissolved organic carbon

• BOD is not harmful to soil if applied appropriately - may increase organic carbon

What is the impact of high Na and K in WWW on soil structure?

• Na and K displace Ca - reducing soil stability

• increases SAR and PAR

• leads to soil dispersion and possibly erosion - especially in clay soils

• poor soil structure can reduce plant growth and water movement

What is the sodium adsorption ration (SAR) and why is it important in WW irrigation?

• SAR = Na / √(Ca+Mg)

• indicates the risk of soil sodicity and dispersion

• high SAR = higher risk of poor soil structure

• SAR should be monitored to protect soil health

What benefits can WWW provide when used appropriately for irrigation?

• increases organic carbon in low OC-soils

• may improve soil microbial activity

• supports recycling of nutrients and water

• enables integrated waste management with crops and livestock

What are the risks of using WWW with high salt content on vineyards?

• salt accumulation in soil - Na and K

• reduced vine growth and possible yield loss

• can cause osmotic stress and toxic ion effects on vines

• may lead to wine quality issues - colour extraction problems in reds

What is the recommended approach to sustainably manage WWW irrigation?

• match WW quality with soil and crop requirements

• monitor SAR, PAR, EC, BOD and nutrients

• use soil amendments (calcium nitrate) to manage ion balance

• integrate with crop rotation and soil health practices

What is meant by “fit for purpose” in WWW treatment?

• treatment tailored to intended use - e.g., land application, reuse, discharge

• balances treatment intensity with environmental risk and economic feasibility

• avoids over-treatment and focuses on key hazards - e.g., salt, BOD

What is the purpose of the slaking and dispersion test in soil management?

• evaluates soil structural stability

• Slaking = breakdown of macoaggregates = low organic matter

• dispersion = breakdown of microaggregates = high Na or K present

• helps decide if soil can withstand WW irrigation

What are some beneficial crops for WWW reuse?

• lucerne, clover grass, maize, sorghum, soybeans

• crops with moderate to high K uptake help reduce soil accumulation

• grapevines: moderate K uptake - 150kg/ha for 15 t/ha yield