Biogas production from the organic fraction of municipal solid waste is enhanced by nickel addition in a two-stage system compared with a conventional digester
Bibliographic record
Abstract
The stability of conventional single-stage anaerobic digestion has limitations and requires strategies to enhance biogas production, including two-stage anaerobic digestion (TSAD) and trace metals addition (Ni2+). This research was focused on determining the effect of the supplementation of different concentrations of Ni2+ on a TSAD compared with a conventional process. In the first stage (hydrogen-producing reactor), the Ni2+ concentrations evaluated were 0, 0.1, and 0.5 mg Ni2+/gVSinoculum. The acidogenic effluents were fed in the second stage to produce CH4-rich biogas. The results showed that it was possible to increase the CH4-productivity and the specific methane production by 72% and 105%, respectively, by operating in TSAD compared with the conventional anaerobic digester. The Ni2+ addition improved the stability of the first and second stages, allowing higher biogas production. The microbial communities’ composition at the phylum level changed in each stage.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".