Can recycling wastewaters be part of the solution to drought-stricken areas — even for sensitive produce such as Napa Valley’s grapevines? Two studies this fall suggest the answer is a qualified yes.
Scientists at the University of California, Davis, studied the effects of reusing industrial waters such as those used for barrel and bottle washing and plant sanitation. They sampled the wastewaters monthly over two years at 18 wineries in the Napa and Lodi regions of California. Though UC Davis researcher Maya Buelow, notes that “growers need to proceed with caution and gather site-specific soil and wastewater data,” under the right conditions, researchers say winery wastewater is a viable water source to irrigate vineyards.
One key concern is the salinity of the reuse waters. Salt concentrations affect how water moves through the soil. Salts usually are introduced by sanitation products but are not removed by treatment systems. Some in the wine industry are switching from sodium-based to potassium-based cleaners to reduce wastewater salinity.
However, specific soils disperse the salts differently based on their composition. Researchers found soils dominated by montmorillonite, a clay mineral, could benefit from shifting to potassium-based cleaners. Testing also showed that both types of cleaners may negatively affect soils dominated by vermiculite, and neither type reduced infiltration rates in soils with kaolinite, another clay mineral.
As you may recall, industrial water treatment was the focus of an hour-long webinar Process Cooling hosted in November. Water guru Paul Puckorius packed a wealth of information about industrial water treatment for cooling towers and evaporative condensers — so much so that we were not able to answer all of the questions during the live event. Fortunately, Paul was able to answer them after the event, and we’ve compiled them into an article that begins on page 12. Paul offers further insights on industrial water treatment and the soon-to-be-released Legionella standards from ASHRAE and the Cooling Technology Institute.
If you haven’t viewed the webinar yet and want to get up to speed, visit http://bit.ly/WaterTreatment2015. There, you can register and login to view the webinar immediately.