Daily nitrogen budget, off-gas N2 closure, EPS composition, and 16S community tables for biochar-dosed anammox SBBRs (days 1–95)
Description
This dataset contains the experimental measurements and derived performance indicators from a 95-day anoxic sequencing batch biofilm reactor (AnSBBR) study evaluating the effect of corncob biochar powder dose on anammox nitrogen removal, nitrate-yield suppression, and nitrogen-removal pathway verification via gas/liquid closure. Four reactors were operated at 32 ± 2°C using polyurethane sponge carriers (50% v/v): R0 (0 g biochar), R1 (0.02 g), R2 (0.2 g), and R3 (2.0 g). The dataset includes daily influent/effluent NH₄⁺-N, NO₂⁻-N, NO₃⁻-N, calculated total inorganic nitrogen (TIN), removal efficiencies (ARE, TNRE), daily nitrogen loading/removal terms (Nin, Nout, Nrem), volumetric nitrogen removal rate (NRR), stoichiometric diagnostics (ΔNO₂/ΔNH₄, NO₃/ΔNH₄, and a nitrate yield proxy), and daily off-gas N₂–N estimates from measured off-gas flow and N₂ fraction with computed closure ratio and N₂/Nrem agreement. To support mechanistic interpretation, the dataset further includes EPS fractionation results (S-EPS, LB-EPS, TB-EPS) with protein/polysaccharide quantification and PN/PS indices, alongside processed 3D-EEM fluorescence outputs. Biofilm samples collected on days 60, 80, and 95 were also subjected to 16S rRNA gene amplicon sequencing; you may optionally include processed community tables and sample metadata to reproduce Bray–Curtis/PCoA/PERMANOVA/RDA analyses reported in the study and link to any external sequence-read accession used in the manuscript.
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Steps to reproduce
1. Reactor operation and phases: Reactors were maintained at pH 7.5 ± 0.2 and operated in three phases with increasing influent nitrogen: P1 (days 1–60; NH4+-N 50 mg/L; NO2--N 75 mg/L; cycle/HRT 24/12/6 h), P2 (days 61–83; 100/150 mg/L; 12 h), and P3 (days 84–95; 200/300 mg/L; 24 h). 2. Liquid-phase chemistry: Influent/effluent samples were filtered (0.45μm) and analyzed for NH4+-N, NO2--N, and NO3--N by the spectrophotometric methods described in the manuscript. 3. Derived metrics (included in the dataset): TIN, ARE, TNRE, daily Nin/Nout/Nrem, NRR, stoichiometric ratios, and the nitrate-yield proxy were computed from the daily concentration time series. 4. Off-gas N2 and closure: Daily off-gas flow rate (Qgas) and dry-gas N2 fraction (XN2) were used to compute QN2 and then N2–N (via the ideal gas law); closure ratio and N2/Nrem agreement were computed from Nin/Nout/Nrem and measured N2–N. 5. EPS and fluorescence: EPS was extracted on days 60, 80, and 95, sequentially fractionated into S-EPS/LB-EPS/TB-EPS, and quantified for protein (Coomassie) and polysaccharide (anthrone-sulfuric) with PN/PS indices. 3D-EEM spectra were acquired using a fluorescence spectrophotometer and processed in OriginPro (or equivalent). 6. Community analyses (optional tables): Biofilm samples (days 60/80/95) were sequenced for 16S rRNA V3–V4; include processed abundance tables and sample metadata to reproduce Bray–Curtis/PCoA/PERMANOVA/RDA and any response-surface TNRE modeling described in the manuscript.
Institutions
- Zhengzhou University
- Taiyuan University of Technology