WARNV5Coulombic mass-balance is open on 7/10 sweep points (>5% closure error). Check substrate consumption + Q_measured.· Logan-group hygiene check; mass balance fundamentals
WARNV6Mean CE × OLR = 76.4 exceeds empirical Logan-group envelope (≤25). Mass transport limits CE at high loading; prediction may be optimistic.· Cheng & Logan 2011 — empirical envelope
Reproducing
Cusick RD, Logan BE (2012) — Bioresource Technology
Phosphate recovery as struvite within a single chamber microbial electrolysis cell
DOI: 10.1016/j.biortech.2011.12.038
Metric
Reported
Predicted
Δ
Band
COD removal
phosphate (PO₄³⁻) removal from solution as struvite precipitate over a single batch cycle at 0.9 V applied; maps to the `substrate` series as a proxy for the nutrient-recovery percentage since the schema does not yet have a `p_recovery_pct` seriesKey
p. 113, Table 1 / §Results
40.0
%
63.0
%
+57.5%
red
H₂ production rate
concurrent H₂ production rate at the stainless-steel cathode while struvite precipitated, 0.9 V applied
p. 113, §Results — paper reports H₂ rates in the bench-MEC range
0.20
m³ H₂ / m³ reactor / d
0.20
m³ H₂ / m³ reactor / d
0.0%
green
Current density
steady-state current density on graphite-brush anode (7 cm² geometric) at 0.9 V applied, single-chamber MEC fed acetate + nutrient-augmented digestate
p. 113, Fig. 2
4.00
A/m²
4.10
A/m²
+2.5%
green
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 (6 items)
Regression-gate anchor for `buildMNRCSweep` phosphorus branch (Wave 3, 2026-05-22). Closure dispatches on recovery_target=phosphorus to use struvite-precipitation kinetics (α=1.4, V_floor=0.4 V, P_max=95%) and applies the COD-limited Monod current factor at 1000 mg/L anolyte COD.
The `substrate` seriesKey is being used as a proxy for P recovery percentage (% PO₄³⁻ removed as struvite). This is INCOMMENSURABLE with the COD-removal meaning of `substrate` elsewhere in the harness. Extending the schema with a `p_recovery_pct` / `n_recovery_pct` key is the right fix; tracked as a follow-up.
The 40% P recovery figure is a single-batch-cycle outcome under the paper's nominal Mg:N:P stoichiometry (paper adjusted to ~1:1:1). Higher recoveries (up to ~70-80%) have been reported in follow-on MNRC work with optimized Mg dosing and longer cycles (Kelly & He 2014 review); the 2012 paper itself reports the more conservative number.
H₂ production rate (~0.2 m³/m³/d) is at the low end of bench-MEC literature; the single-chamber configuration suffers H₂ recycling losses (cathode H₂ re-oxidized at anode) that two-chamber MECs avoid. The paper trades this for the struvite-recovery capability.
Current density (~4 A/m²) is reported on the geometric brush-anode area (~7 cm²); the brush's effective surface area is ~70× higher, so the "per-actual-surface" current density is much lower. Use the geometric number to compare across papers.
Real wastewater performance will differ substantially from synthetic digestate; Mg, Ca, and competing precipitates (calcium phosphates, hydroxyapatite) complicate struvite specificity. The 2012 paper is a controlled-condition baseline.