ERRORV11Predicted V_cell 1.500 V exceeds H₂O electrolysis Gibbs voltage 1.23 V at pH 7. Check model or operating point.· Thermodynamics (Nernst); Bard & Faulkner ch. 6
WARNV14Peak power 9184 mW/m² exceeds MFC typical ceiling (3-5 W/m²). Verify area basis; world record is ~1550 mW/m² (Fan et al. 2008).· Fan et al. 2008 — 10.1021/es8019647
WARNV5Coulombic mass-balance is open on 10/10 sweep points (>5% closure error). Check substrate consumption + Q_measured.· Logan-group hygiene check; mass balance fundamentals
Understanding Ammonium Transport in Bioelectrochemical Systems towards its Recovery
DOI: 10.1038/srep22547
Metric
Reported
Predicted
Δ
Band
Current density
Peak current density in MNRC for ammonium recovery, V_app=0.9 V; 2-chamber MEC with CEM and Pt cathode
Fig. 2a — "The maximum current density was 1.89 A m⁻² (Fig. 2a)."
1.89
A/m²
6.12
A/m²
+224.0%
red
Coulombic efficiency
Coulombic efficiency for MNRC operation at V_app=0.9 V — ammonium recovery via cation-flux across CEM. Lower than struvite-mode MNRC because NH₄⁺ migration competes with HER current.
Text — "resulting in a Coulombic efficiency (CE) of 34.7 ± 5.9%"
34.7
%
36.9
%
+6.3%
green
COD removal
Nitrogen recovery as ammonia (% of influent N stripped + absorbed by acid trap). The `substrate` series in this preset means N-recovery percentage per the recovery_target=nitrogen dispatch in `buildMNRCSweep`.
Text — "66.2 ± 2.7% was stripped out as ammonia and absorbed by the sulfuric acid"
66.2
%
90.9
%
+37.3%
amber
Δ-bands per Logan & Regan 2006 lab-to-lab reproducibility envelope: green ≤±25%, amber ±25–50%, red >±50%. Predictions from Butler-Volmer + Ohmic + Tafel closure calibrated against the Logan corpus (regression-tested in butler-volmer-calibration.test.ts).
What we don't know about this paper (3 items)
The `substrate` seriesKey maps to N-recovery percentage when recovery_target=nitrogen (per the dispatch in `buildMNRCSweep`). This is a different semantic from the COD-removal meaning of `substrate` elsewhere in the harness — the recovery_target field is what disambiguates.
CE = 34.7% reflects the cation-flux loss when NH₄⁺ migration competes with HER current across the CEM. The Pt cathode kinetics for HER are very fast, so a portion of the electrical current is consumed making H₂ rather than driving NH₄⁺ across the membrane. The closure encodes this as ceArchFactor = 0.41 (vs 0.85 for P-struvite mode).
V_app = 0.9 V is the lab operating point. The N-recovery curve V_floor_N = 0.3 V is lower than struvite V_floor = 0.4 V because NH₄⁺ migration begins as soon as current flows, while struvite needs a pH-rise threshold for nucleation.