Wheat Growth and Soil Nutrient Response to Novel Electrochemically‐Treated Wastewater Solids Produced at Bench Scale

ABSTRACT Soil amendments and fertilizer products developed from municipal or agricultural waste streams, such as biosolids or livestock manure, are crucial to foster circular nutrient economies and reduce agricultural production costs, as well as to mitigate environmental impacts compared to traditional inorganic fertilizers. However, innovative technologies are required to develop municipal wastewater solids‐based fertilizers that are safe and effective for environmental application while reducing production costs and energy consumption compared to current technologies. A greenhouse pot experiment was conducted to assess the effects of novel municipal wastewater solids‐based products in the early stages of technological development at bench scale on plant growth and soil properties. Electrochemically‐treated waste activated sludge (EWAS), untreated waste activated sludge (WAS), a commercially available fertilizer produced from municipal wastewater solids (Milorganite), or a commercially available inorganic fertilizer (Greenview) was applied to pots containing wheat ( Triticum aestivum ) grown in field‐collected agricultural soil. Soil pH was higher with EWAS and Milorganite at the end of the 80‐day growth period, while Greenview‐treated soil had higher EC. Extractable soil P was 30% higher, while exchangeable soil Na was twice as high with EWAS as in unamended control soils. Wheat biomass was also significantly greater with EWAS compared to unamended controls and was comparable to the commercial fertilizers. This study demonstrates the potential efficacy of electrochemically‐treated wastewater solids as an amendment in field‐collected soil and highlights the need for further technological development of novel electrochemical processes designed to extract excess nutrients and deactivate pathogens in wastewater solids to create economically viable products while consuming less energy than conventional treatment methods.