Impact of temperature on performance, microbiological, and hydrodynamic aspects of UASB reactors treating municipal wastewater
Bibliographic record
Abstract
The present study examined the feasibility of treating municipal wastewater by a UASB system under low-temperature conditions. Two reactors were started-up at 20 degrees C and subsequently operated at temperatures of 32, 20, 15, 11, and 6 degrees C applying several hydraulic retention times (HRTs) ranging from 48 to 3 h during an operational period of approximately 900 days. Chemical oxygen demand (COD) removal efficiency ranged from 70 to 90% up to an HRT of 6 h and 11 degrees C. The performance of the reactor was not very satisfactory during 6 degrees C operation (average COD removal 40%). Sulfate reduction played an important role in COD reduction. Digital image analysis and scanning electron microscopic observations of sludge samples revealed aggregation of biomass in the form of irregular shaped granules (mean size ranged from 1.5 to 3.0 mm). The hydraulic regime in the reactor was impacted by the change in operating temperature. This study demonstrated that the UASB system could be applied successfully for pre-treatment/treatment of municipal wastewater under low-temperature conditions.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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 | 0.000 |
| 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".