Thermophilic anaerobic acid digestion of biosolids: hydrolysis, acidification, and optimization of retention time of acid digestion
Bibliographic record
Abstract
The objective of the study was the optimization of the retention time in a thermophilic acid digestion system. To achieve this optimization, acidification index defined as the ratio between acidification rate and hydrolysis rate was used. First-order reaction model developed by Eastman and Ferguson (1981) was used to describe hydrolysis of particulate matter in sludge. The first-order hydrolysis rate constant was found to be 2.36 d–1, and the initial concentration of degradable particulate COD was found to be 10.4 g/L. A model of acid digestion was proposed that included acidogenic biomass growth and decay. The total acidogenic population was estimated and kinetic parameters of acidogenic population were specific growth rate 0.78 d–1, net specific growth rate 0.25 d–1, decay coefficient 0.52 d–1, and observed yield 0.05 mg biomass / mg COD consumed. Based on the acidification index, the optimum retention time in a thermophilic acid digester was 3–3.5 d. Key words: wastewater sludge, biosolids, anaerobic digestion, hydrolysis, acidification, kinetics.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".