Ozone enhances biodegradability of heavy hydrocarbons in soil
Bibliographic record
Abstract
The molecular complexity and the low solubility of petroleum hydrocarbon residuals in weathered soil hinder bioremediation as a clean-up strategy. Pretreatment with advanced oxidation, such as with ozone gas (O3), is a means to transform recalcitrant organics to more biodegradable forms. The efficacy of gas-phase ozone for enhancing the biodegradability of heavy residual petroleum hydrocarbons in weathered soil was tested. Ozonating soil containing ∼1% (w/w) residual petroleum hydrocarbons with a dose of 6 kg ozone/kg initial total petroleum hydrocarbons (TPHs) achieved nearly 50% TPH reduction, simultaneous with a >20-fold increase in soluble chemical oxygen demand, but with a ≤12% loss of total organic carbon. TPH molecules were converted to partly oxidised products, ten of which were identified as n-monocarboxylic acids, which were readily biodegraded, and ozonation resulted in a fourfold increase in 5-d biochemical oxygen demand (BOD5). BOD5 results after ozonation were the same with or without a microbial seed, which suggests that bioaugmentation is likely not necessary after ozonation. Deoxyribonucleic acid sequencing over the time course of the BOD5 tests showed increased diversity and changes in predominant genera, both of which underscore that ozonation made the heavy hydrocarbons readily biodegradable for soil bacteria.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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".