Pilot-scale evaluation of poultryponics: insights into nitrogen utilization and food pathogen dynamics

Authors: WELLINGTON, ARTHUR - Auburn University; MORGAN, ZACH - Auburn University; REINA ANTILLON, MARCO - Auburn University; DRABOLD, EDWARD - Auburn University; WELLS, DANIEL - Auburn University; BOURASSA, DIANNA - Auburn University; WANG, QICHEN - Auburn University; HIGGINS, BRENDAN - Auburn University

Submitted to: ACS Environmental Science & Technology Water
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2024
Publication Date: 9/13/2024
Citation: Wellington, A., Morgan, Z., Reina Antillon, M., Drabold, E., Wells, D.E., Bourassa, D.V., Wang, Q., Higgins, B.T. 2024. Pilot-scale evaluation of poultryponics: insights into nitrogen utilization and food pathogen dynamics. ACS Environmental Science & Technology Water. 4(9):3964-3975. https://doi.org/10.1021/acsestwater.4c00262.
DOI: https://doi.org/10.1021/acsestwater.4c00262

Interpretive Summary: Poultry processing generates billions of gallons of wastewater every year. Every chicken that gets processed generates about 7 gallons of water that is rich in nutrients. These nutrients, such as nitrogen and phosphorus, pollute the environment if not treated properly. As a result, most processing plants simply discharge their wastewater to the sewer system where it is treated by the city's wastewater treatment plant, thus removing the nutrients. However, these nutrients are potentially valuable for crop production. We therefore designed and tested a pilot scale treatment system that treats poultry processing wastewater , eliminating pathogens like Salmonella, and converting the nutrients into a form that plants can use. We operated the system over 200 days, using real wastewater from a poultry processing plant. In this period, we conducted 4 lettuce growth campaigns and showed that our treatment system could generate water that was free of pathogens and suitable for lettuce growth. Our system was particularly remarkable because we did not resort to costly filtration methods to achieve this result. We used cost-effective treatment systems, increasing the likelihood of adoption.

Technical Abstract: Poultry processing wastewater (PPW) is a nutrient-rich effluent with potential for reuse in crop irrigation. This study investigated transforming PPW into a hydroponic nutrient solution using a pilot scale “poultryponics” system operated continuously for 222 days. The system treated ~57 L d-1 of real PPW and consisted of bioreactors (inoculated with a consortium of microalgae and nitrifying bacteria), clarifiers, membrane filters, UV disinfection, and a deep-water hydroponic system. The system was evaluated in terms of nitrogen transformation, organic removal efficiency, and pathogen levels. Although soluble organic removal efficiencies (sCOD) were high (>80%) in all bioreactors, nitrification was limited due to high organic loading (350 - 800 mg sCOD L-1), relatively short retention time (24 h), and low dissolved oxygen levels (< 3.5 mg O2 L-1). Grow beds showed significant nitrification, indicating the importance of upstream organic removal. CO2 supplementation (0.5% v/v) in bioreactors did not promote nitrification in the bioreactors but was beneficial for nitrification in grow beds by pH-modulating effects. Microbiological analyses showed no Salmonella detection in or after bioreactors and substantial reductions in total coliforms (~40%) and aerobic plate counts (~30%) after UV treatment. These findings demonstrate the sustainable and safe reuse of nutrient-rich industrial effluents in agriculture.