Agriculture accounts for up to 80% of the total U.S consumptive water use. Increasing water scarcity and severity of droughts have accelerated the need for alternate water sources, including the use of reclaimed wastewater for irrigation and other agricultural operations. However, concerns over wastewater-borne pathogens and emerging contaminants necessitate effective treatment methods. In our short-term study, we evaluated a novel integrated electrodialysis-forward osmosis (iEDFO) method for wastewater treatment and its impact on southern highbush blueberry (Vaccinium corymbosum L.) grown in soilless media. Plants were fertigated with untreated municipal or dairy digestate, recovered nutrient water from the digestates treated by iEDFO, or a modified Hoagland solution (control). Leaf area and shoot biomass were similar across all treatments, indicating no adverse effects of the treated and untreated digestates on growth. While salinity levels exceeded threshold for blueberry (> 2 dS·m-1), periodic freshwater flushing mitigated osmotic stress in the plants. Nutrient analysis indicated high potassium levels amongst all treatments, suggesting the need for adjustments to optimize nutrient balance in each solution. Mass spectrometry confirmed significant removal of pharmaceuticals and pesticides (>90%), demonstrating effectiveness of iEDFO in treating reclaimed water for potential pathogens and reducing potential human health risks. A longer-term study is currently underway to assess the viability of the iEDFO system and its enduring impact on crop performance and potential contaminants in the fruit. In this case, 2-year-old ‘Star’ blueberry plants were transplanted to 25-L containers filled with soilless media and irrigated three times a week with untreated municipal digestate, recovered nutrient water from the digestates treated by iEDFO, or a modified Hoagland solution. Initial findings showed that while the control had the overall highest plant growth, treatments did not differ in cane or stem mass or visible root growth. Leaf macro- and micronutrients were also similar amongst the treatments, except for boron, which was highest with municipal wastewater. This summer, we will evaluate the effects of these treatments on production and quality of the fruit.
