Forschungsdaten – Titel und Zusammenfassungen von Publikationen, extrahierte Daten und Katalogeinträge – erscheinen in ihrer Originalsprache Englisch.
Performance of a Trickling-Bed Biocathode Microbial Electrochemical System Treating Domestic Wastewater and Functional Microbial Community Characteristics
Haiman Wang, Zhuang Miao, Lei Chao, Yafeng Li +1
KI-Zusammenfassung
82 % KonfidenzA trickling-bed biocathode MES (TB-MES) integrating biotrickling filters with a biocathode chamber achieved 84.6% ammonia-N removal and 70.1% total nitrogen removal on domestic wastewater at 48 h HRT and 200 mL/min catholyte recirculation, generating 3.2 W/m³ without mechanical aeration. Spatial DO gradients (2.3 mg/L upper to 0.7 mg/L lower) enabled stratified nitrifier (Nitrosomonas, 20.4% upper) and denitrifier (Azoarcus, 12.6% lower) communities. Higher recirculation rates (400 mL/min) boosted power density to 6.7 W/m³ but reduced TN removal to 60.3%, revealing a critical trade-off between energy output and nitrogen removal efficiency.
Zentrale Erkenntnisse
Zielkonflikt Catholyte recirculation rate of 200 mL/min is optimal: power density 3.8 W/m³ with TN removal 79.7%, but 400 mL/min increases power to 6.7 W/m³ while TN removal drops to 60.3%
Was heißt das. Operators must choose between maximizing power output or nitrogen removal; 200 mL/min is the sweet spot for domestic wastewater unless energy recovery is the sole priority
Mechanismus DO concentration gradient from 2.3 mg/L (upper) to 0.7 mg/L (lower) at 200 mL/min recirculation creates spatial niche partitioning: Nitrosomonas dominates upper (20.4%) where DO is high, Azoarcus dominates lower (12.6%) where DO is low
Was heißt das. Design cathode geometry and recirculation to maintain DO >2 mg/L in upper zone for nitrification and <1 mg/L in lower zone for denitrification; avoid over-oxygenation which inhibits denitrification
Schwellenwert At 400 mL/min recirculation, DO at lower sampling points rises to 1.5–2.2 mg/L, inhibiting denitrification and causing nitrate/nitrite accumulation (11.6 ± 1.2 mg/L), reducing TN removal by 24.1% versus 200 mL/min
Was heißt das. Maintain lower-zone DO <1 mg/L to prevent denitrification inhibition; if recirculation must increase for power, add anoxic compartments or reduce aeration intensity
Mechanismus Ammonia-N removal improves monotonically with recirculation (53.4% at 50 mL/min → 89.1% at 400 mL/min), but TN removal peaks at 200 mL/min (79.7%) and declines thereafter, indicating nitrification is not the bottleneck—denitrification is
Was heißt das. Nitrification capacity is robust across recirculation rates; focus optimization on maintaining anoxic zones for denitrification rather than improving nitrification
Schwellenwert Coulombic efficiency of 57.1% on domestic wastewater means >half of organic matter (214.6 mg COD/d) is converted to electricity, not just respired; anode effluent COD of 78 ± 9 mg/L is low enough to prevent heterotrophic bacteria from outcompeting cathodic autotrophs
Was heißt das. Maintain anode effluent COD <100 mg/L to preserve cathodic autotroph dominance and electricity generation; higher COD loads will shift cathode to heterotrophic denitrification, reducing bioelectrochemical benefit
Widersprüche1
Nur Konflikte, die die Publikation selbst zeigt, jeweils am Text geprüft.
Innerhalb der Publikation Ammonium removal increases monotonically with recirculation rate, but total nitrogen removal peaks and then declines, suggesting nitrification and denitrification respond oppositely to increased aeration
Eine SeiteAmmonium nitrogen removal increased from 53.4 ± 1.6% to 89.1 ± 3.6% as recirculation increased from 50 to 400 mL/min
“Ammonium nitrogen removal gradually increased from 53.4 ± 1.6% to 89.1 ± 3.6% as the recirculation rate increased from 50 mL min⁻¹ to 400 mL min⁻¹”
Andere SeiteTotal nitrogen removal decreased from 79.7 ± 2.5% to 60.3 ± 2.8% as recirculation increased from 200 to 400 mL/min
“the TN removal decreased from 79.7 ± 2.5% to 60.3 ± 2.8% as the recirculation rate increased from 200 mL min⁻¹ to 400 mL min⁻¹”
Einordnung der Autoren. Authors attribute this to increased DO at lower sampling points (1.5–2.2 mg/L at 400 mL/min) inhibiting denitrification, while nitrification is not oxygen-limited. The trade-off is real and expected: higher aeration favors nitrification but inhibits the anoxic denitrification step needed for complete nitrogen removal.
Ansatzpunkte6
Konkrete Lücken in dieser Publikation, jeweils mit einem Experiment, das sie schließen würde.
Hoch No measurement of N₂O accumulation or emission across the recirculation rate range (50–400 mL/min), despite N₂O being a known byproduct of incomplete denitrification under high DO or high nitrite conditions
At 400 mL/min, DO rises to 1.5–2.2 mg/L in lower zones and nitrite accumulates (11.6 ± 1.2 mg/L), both conditions favoring N₂O production; paper does not report N₂O or measure it
Versuch. Measure N₂O in gas phase and dissolved phase at 50, 200, 400 mL/min recirculation; correlate with DO profile and nitrite concentration
Hoch No systematic variation of cathode potential or applied voltage; only external resistance was varied (500–10 Ω), leaving the effect of cathodic potential on nitrification vs. denitrification partitioning unexplored
Cathode potential drives both oxygen reduction and denitrification; paper states 'the system was operated...with the whole acclimation period lasting for nearly 500 h' but does not report actual cathode potentials achieved or test potentials as an independent variable
Versuch. Operate at fixed cathode potentials (e.g., −0.3, −0.5, −0.7 V vs. Ag/AgCl) while maintaining 200 mL/min recirculation; measure nitrification, denitrification, and power output
Mittel No investigation of C/N ratio effects; synthetic medium had fixed C/N ratio (~4.4 based on 0.71 g/L sucrose and 0.16 g/L NH₄Cl), and domestic wastewater was not manipulated
Paper notes heterotrophic denitrification competes with bioelectrochemical denitrification but does not test whether C/N ratio shifts the balance; text states 'direct contact with solutions containing high concentrations of organic matter would make the heterotrophic bacteria out-compete the cathodic autotrophic bacteria'
Versuch. Feed synthetic medium with C/N ratios of 2, 4, 8, 16 at 200 mL/min recirculation; measure heterotrophic vs. bioelectrochemical denitrification contribution via isotope labeling or electron balance
Mittel No measurement of nitrite accumulation or N-species distribution in the cathode chamber over time; only final effluent concentrations reported (NO₃⁻-N 5.7 ± 0.9, NO₂⁻-N 0.6 ± 0.4 mg/L on wastewater)
Nitrite is a key intermediate and can accumulate under high DO or low pH; paper does not profile nitrite along the cathode height or over time, limiting understanding of denitrification bottlenecks
Versuch. Sample NO₂⁻-N at Points A, B, C, D (upper to lower cathode) at 50, 200, 400 mL/min; measure temporal dynamics during transient shifts in recirculation rate
Mittel No test of HRT variation; system operated at fixed 48 h HRT throughout, despite HRT being a critical parameter for nitrogen removal kinetics and biofilm maturation
Paper states 'The system was operated at a hydraulic retention time (HRT) of 48 h' but does not explore shorter (24 h) or longer (72 h) HRTs, which would affect substrate availability, biofilm thickness, and denitrification completeness
Versuch. Operate at HRT 24, 48, 72 h with 200 mL/min recirculation on domestic wastewater; measure ammonia, TN removal, and power density
Mittel No investigation of catholyte pH control or buffering; domestic wastewater was unbuffered and pH fluctuated (7.2 ± 1.6), yet no pH optimization was performed despite nitrifiers and denitrifiers having distinct pH optima
Paper notes 'due to the unbuffered condition in domestic wastewater, it might be difficult to maintain the pH in the range suitable for the growth of microorganisms' but does not test pH adjustment or buffering
Versuch. Operate at fixed pH 6.5, 7.0, 7.5, 8.0 using phosphate buffer at 200 mL/min recirculation; measure nitrification, denitrification, and microbial community shift
Erstellt von der MESSAI-Extraktionspipeline · mit dem Quell-PDF abgleichen
Zusammenfassung
Biocathode microbial electrochemical systems (MESs) that remove nitrogen compounds out of wastewater are of special interest for practice. High energy-input for aeration is one of the barriers that hinder their application on a wider scope. A trickling-bed biocathode MES (TB-MES) was developed by integrating biotrickling filters with a biocathode MES. By recirculating the catholyte and sprinkling it through a spray nozzle, the system was able to achieve a reoxygenation process, which could facilitate the creation of an aerobic and anoxic environment. At an optimal recirculation rate of 200 mL min⁻¹, the TB-MES removed 87.2 ± 2.7% of ammonium nitrogen and 79.7 ± 2.5% of total nitrogen (TN), and simultaneously achieved a maximum power density of 3.8 ± 0.3 Wm−3. Comparable performances were achieved when treating domestic wastewater, which were 84.6 ± 2.4%, 70.1 ± 4.2%, and 3.2 ± 0.2 W m⁻³ for ammonium nitrogen removal, TN removal, and maximum power density. Pyrosequencing analysis revealed Nitrosomonas was more abundant in the upper portion of the carbon fiber brush biocathode (CFBup, 20.4%) and Azoarcus was more abundant in the lower portion (CFBbottom, 12.6%), which was probably caused by the difference in dissolved oxygen concentration in different parts of the biocathode. The TB-MES shows great promise for domestic wastewater treatment by employing biotrickling filters for oxygen supply in biocathode MES.
Schlagwörter
Kennungen
- Zeitschrift
- Applied Sciences
- Jahr
- 2020
Dieser Publikation ist noch kein 3D-Modell zugeordnet. Die Parameterbereiche oben ordnen die berichteten Werte trotzdem in die Literaturverteilung ein.