Evaluation of PCBs biodegradability in sludges by various microbial cultures
Bibliographic record
Abstract
Abstract The application of aerobic and anaerobic treatment for removal of PCBs in sludges generated from a groundwater treatment system was investigated. The sludge was characterized by PCB concentrations of > 520 ppm, with Aroclors 1254 and 1260 accounting for 26 and 74%, respectively, as well as total organic carbon (TOC), and oil and grease (O&G) concentrations of 108,500 and 18,600 mg/L, respectively. Four treatments were explored: three aerobic and one anaerobic. Two types of bacterial innocula were aerobically tested: sludge from a poultry processing wastewater treatment plant, and a commercial seed (Petrobio®). Petrobio was tested aerobically with and without a biosurfactant/enzymes product (BOD‐Balance™), and was also tested anaerobically. Over a period of 60 days, PCB concentrations on a volumetric and solids basis were reduced by 73.4 to 88.0% and 64.7 to 80%, respectively. Aroclors 1254 and 1260 concentrations decreased by about 76 to 89%, and 73 to 89%, respectively. TOC and O&G removal efficiencies ranged from 77 to 93%, and from 52 to 86%, respectively. Generally, sludge from the poultry processing facility achieved the best results and exhibited the most rapid biodegradation kinetics. Aerobic PCB biodegradation rates for Aroclors 1254 and 1260 were 13.5% and 23%, respectively, faster than the anaerobic biodegradation rates. Overall PCB biodegradation kinetics conformed to first‐order, with rate constants ranging from 0.017 d −1 under anaerobic conditions to 0.022 d −1 under aerobic conditions, while both TOC and O&G biodegradation kinetics followed first‐order kinetics, with rate coefficients in the ranges of 0.025–0.047 and 0.014 and 0.04 d −1 , respectively.
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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 | 0.001 | 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) | 0.014 | 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".