Nitrite Interference with Soluble COD Measurements from Aerobically Treated Wastewater
Bibliographic record
Abstract
This study aimed to determine the interference of nitrite (<inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm01.gif"/>) with soluble chemical oxygen demand (COD) measurements from the effluent of landfill leachate treated by sequencing batch reactors (SBRs). Synthetic wastewater assimilating young and old landfill leachate was used as influent for SBR1 and SBR2, respectively. A mixture of raw wastewater and landfill leachate was used as influent for SBR3. Due to the high ammonia concentration in the influent, different levels of partial nitrification were observed in all the reactors and <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm12.gif"/> was detected in the effluents. Theoretically, when <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm23.gif"/> is present in the effluent, 1 mg/L of <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm34.gif"/> accounts for 1.1 mg/L of COD (i.e., 1.1 mg COD/mg <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm36.gif"/>) due to the oxidation of <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm37.gif"/> to <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm38.gif"/>. It was found that the value of 1.1 mg COD/mg <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm39.gif"/> was 3 times higher than the values obtained in the experiments with SBR1 and SBR3. In addition, the values obtained in the experiments with SBR2 were much higher than 1.1 mg COD/mg <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm40.gif"/>. These results suggest that the theoretical value of 1.1 mg COD/mg <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00549-ilm02.gif"/> cannot be applied to predict the COD values caused by nitrite in the tested wastewaters. To obtain an accurate measurement of soluble COD in samples that contain nitrite, nitrite should be eliminated before the measurements.
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.009 |
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".