Chemical Leaching of Metals from Wastewater Sludge: Comparative Study by Use of Three Oxidizing Agents [H <sub>2</sub>O <sub>2</sub>, FeCl <sub>3</sub>, and Fe <sub>2</sub>(SO <sub>4</sub>) <sub>3</sub>]
Bibliographic record
Abstract
Chemical leaching of the toxic metals (cadmium, chromium, copper, nickel, lead, and zinc) and behavior of other elements (aluminum, calcium, iron, potassium, magnesium, manganese, sodium, phosphorus, and sulfur) in the wastewater sludge of the Montreal Urban Community wastewater treatment plant (Montreal, Quebec, Canada) were studied in 2-L beakers using sulfuric acid and three oxidants [H2O2, FeCl3, and Fe2(SO4)3] and their association. Metal removal efficiencies of these oxidants were evaluated under different conditions of pH (2.0 and 2.5) and oxidation-reduction potential (ORP) (350 to 500 mV). The solubilization of the different elements was linked to pH and/or ORP, and a period of 2 to 4 hours was required to obtain satisfactory metals removal yields. Sludge-fertilizing properties generally were little affected by the decontamination process, especially for processes using a ferric salt. Finally, optimal conditions, for best metals solubilization, were established at pH 2.5 and ORP = 450 mV in a 4-hour period.
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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 | 0.005 | 0.000 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.002 | 0.004 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.000 | 0.001 |
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; both teacher heads agree on what is shown here.
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".