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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #426611
Research Project: Innovative Manure Treatment Technologies and Enhanced Soil Health for Agricultural Systems of the Southeastern Coastal Plain

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: Enhancing anaerobic digestion of nitrogen-rich substrates through in situ ammonia recovery using tubular gas-permeable membranes

Author
item FERRI DA SILVA, JOAO FERNANDO - Western Paraná State University
item TAPPARO, DEISI CRISTINA - Embrapa-Pigs And Poultry
item LAZAROTO, ANA CLAUDIA - Federal University Of Parana Polytechnic Center
item BELTRAME DE ASIS, DAGMARA - Federal University Of Parana Polytechnic Center
item MACHADO SOPHIATTI, IGOR VINICIOUS - Universidade De Caxias Do Sul
item MAGRINI, FLAVIANE EVA - Universidade De Caxias Do Sul
item STEINMETZ, RICARDO LUIS - Embrapa-Pigs And Poultry
item GOLDSCHMIDT ANTES, FABIANE - Embrapa-Pigs And Poultry
item Vanotti, Matias
item PAESI, SUELEN - Universidade De Caxias Do Sul
item KUNZ, AIRTON - Universidade De Caxias Do Sul

Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/31/2025
Publication Date: 8/5/2025
Citation: Ferri Da Silva, J., Tapparo, D., Lazaroto, A., Beltrame De Asis, D., Machado Sophiatti, I., Magrini, F., Steinmetz, R., Goldschmidt Antes, F., Vanotti, M.B., Paesi, S., Kunz, A. 2025. Enhancing anaerobic digestion of nitrogen-rich substrates through in situ ammonia recovery using tubular gas-permeable membranes. Bioresource Technology. 437. https://doi.org/10.1016/j.biortech.2025.133063.
DOI: https://doi.org/10.1016/j.biortech.2025.133063

Interpretive Summary: Among the alternatives for improving manure management, anaerobic digestion (AD) anaerobic digestion (AD) emerges as a mature and versatile technology. However, high levels of total ammoniacal nitrogen (TAN) in manure reduces the potential production of methane (CH4) biogas due to inhibition of the microorganisms (methanogens). In the present study, the effect of TAN removal using gas-permeable membrane (GPM) technology on AD process performance and CH4 yield was investigated using swine manure feedstock. The GPM technology has proven to be an effective strategy for TAN removal, stabilizing the AD reactor, and recovering nitrogen in a matketable, concentrated ammonium salt. During the first 80 days, when the concentration of free ammonia (FA) was below 275 mg per liter, the CH4 production was 200 L per kg of volatile solids (VS) in the manure. Later, when FA levels exceeded 500 mg per liter as a result of adding urea-nitrogen (typical of urine), the CH4 production in the bioreactors decreased by 50%, and when FA levels reached 700 mg per liter, the methane production decreased by 70%, resulting also in significant changes in the microbial community. Even after the acute inhibition, activating the GPM system restored methane production to the higher initial levels when the reactors were healthy, demonstrating its effectiveness as both a preventive and corrective strategy. The reactor's successful recovery, utilizing GPM for in situ ammonia removal, represents a promising strategy for controlling AD process stability under high TAN concentrations, enabling methane yield recovery and facilitating ammonium reuse as fertilizer. These findings support the implementation of GPM as a key strategy to improve the robustness and sustainability of anaerobic digestion systems treating nitrogen-rich substrates.

Technical Abstract: To mitigate ammonium inhibition in anaerobic digestion, the use of ePTFE gas-permeable membranes (GPM) was tested. Two semi-continuous stirred tank reactors at the laboratory scale were operated with swine manure and urea as a source of total ammoniacal nitrogen (TAN). One reactor was equipped with GPM, while the other served as a control. After a significant drop in methane yield (MY), the GPM system was activated. Weekly samples were collected to monitor TAN, the VFA/TA ratio, and volatile solids. The MY and the biogas composition were continuously analyzed. In addition, taxonomic analyses were performed at three strategic points throughout the process. During the first 80 days, the concentration of free ammonia (FA) was below 275 mgN L-1, with MY close to 200 LCH4 kgVS-1 in both reactors. When FA levels exceeded 500 mgN L-1, MY decreased by 50%. At FA of 700 mgN L-1, inhibition reached 70%, resulting in significant changes in the microbial community. Clostridium_sensu_stricto_1, HN-HF0106, and Fastidiosipila exhibited increased abundance at high free ammonia concentrations. The archaeal community was dominated by Methanosarcina, which showed greater tolerance to stress caused by excess ammonia. Even after acute inhibition, activating the GPM system reduced FA and restored methane production, demonstrating its effectiveness as both a preventive and corrective strategy. The reactor's successful recovery, utilizing GPM for in situ ammonia removal, represents a promising strategy for controlling reactor stability under high TAN concentrations, enabling methane yield recovery and facilitating ammonium reuse as fertilizer.