The Effect of Short-Term Dissolved Oxygen Transients on Activated Sludge
Bibliographic record
Abstract
Abstract The effect of short-term dissolved oxygen (DO) disturbances on municipal activated sludge was studied, in a batch system, with respect to changes in supernatant turbidity, suspended solid (SS) concentrations, proteins, polysaccharides, and cations in the extracellular polymeric substances (EPS). Results showed that turbidity increased by 20 times when the DO concentration decreased below 0.5 mg/L, and supernatant SS concentrations increased by 1 to 2 times with DO reduction, implying the presence of more unsettled particles in the supernatant. Concomitantly, soluble proteins increased from less than 1 mg/L to up to 30 mg/L, and bound proteins decreased by more than 15% under DO limitation. Further enzymatic tests confirmed that, compared with polysaccharides, proteins were more involved in preventing sludge deflocculation. The DO stress also caused significant changes in the bulk concentrations of K+ and Ca2+; K+ increased by 40% and Ca2+ decreased by 30%. When the DO concentration was restored after 6 hours, reversible changes were observed in supernatant turbidity and SS, and concentrations of EPS proteins and cations, indicating a possible physiological response of microorganisms to a short-term low DO disturbance.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".