Chemical and microbiological changes in laboratory incubations of nitrate amendment "sour" produced waters from three western Canadian oil fields
Bibliographic record
Abstract
Nitrate addition to oil field waters stops the biogenic formation of sulfide because the activities of nitrate-reducing bacteria (NRB) suppress the activities of sulfate-reducing bacteria (SRB). In general, there are two types of NRB - the heterotrophic NRB and the chemolithotrophic NRB. Within the latter group are the nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB). To date, no study has specifically addressed the roles of these different NRB in controlling sulfide concentrations in oil field produced waters. This study used different culture media to selectively enumerate heterotrophic NRB and NR-SOB by most probable number (MPN) methods. Produced waters from three sulfide-containing western Canadian oil fields were amended with nitrate as an electron acceptor, but no exogenous electron donor was added to the serum bottle microcosms. Changes in the chemical and microbiological characteristics of the produced waters were monitored during incubation at 21 degrees C. In less than 4 days, the sulfide was removed from the waters from two of the oil fields (designated P and C), whereas nearly 27 days were required for sulfide removal from the water from the third oil field (designated N). Nitrate addition stimulated large increases in the number of the heterotrophic NRB and NR-SOB in the waters from oil fields P and C, but only the NR-SOB were stimulated in the water from oil field N. These data suggest that stimulation of the heterotrophic NRB is required for rapid removal of sulfide from oil field-produced waters.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".