By Andi Anderson
Iowa State University researchers are pioneering a novel approach to enhancing water quality bioreactors for nitrate reduction in agricultural landscapes. By investigating the use of corn cobs as an alternative carbon source, they aim to improve the efficiency and affordability of these critical environmental remediation systems.
Traditionally, water quality bioreactors utilize woodchips to facilitate the transformation of nitrate-nitrogen in tile drainage water from crop fields. However, the supply of woodchips can be limited, prompting researchers to explore alternative materials. Dr. Michelle Soupir and her team at Iowa State's Agricultural and Biosystems Engineering department embarked on a project to evaluate the viability of corn cobs as a substitute.
Their findings, published in the Journal of Environmental Management, revealed promising results. Bioreactors filled with a mixture of corn cobs and woodchips demonstrated higher nitrate removal rates compared to those filled with woodchips alone. Moreover, the corn cob bioreactors exhibited similar hydraulic properties to woodchips, ensuring efficient water treatment processes.
One of the most significant advantages of corn cobs is their potential for cost savings. Economic evaluations showed that bioreactors utilizing corn cobs could achieve up to a 60% reduction in costs per unit of nitrogen removed compared to woodchip-only systems. Additionally, corn cobs exhibited slower degradation rates, suggesting a longer lifespan and reduced maintenance requirements.
These promising findings, the researchers encountered challenges related to the availability of corn cobs in sufficient quantities. Filling a field-scale bioreactor requires substantial volumes of material, posing logistical hurdles for sourcing and transportation. However, ongoing efforts are underway to identify potential suppliers, including seed corn companies, to meet the demand.
The research team is exploring various avenues to further optimize water quality bioreactors. Future studies will investigate the efficacy of bioreactors using 100% corn cobs as a carbon source, funded by a Conservation Innovation Grant. Additionally, researchers are exploring alternative carbon sources and strategies to increase bioreactor effectiveness, such as optimizing flow rates.
Water quality bioreactors represent a vital tool in mitigating agricultural nutrient pollution, aligning with Iowa's commitment to improving environmental sustainability. By leveraging innovative approaches like corn cobs, Iowa State University researchers are advancing the next generation of bioreactor technology, with the potential to enhance water quality and agricultural productivity.
Photo Credit: gettyimages-dale-fornoff
Categories: Iowa, Crops, Corn, Education