Evaluation of the ability of chlorine to inactivate selected organisms from the biofilm of a drinking water distribution system simulator following a long-term wastewater cross-connection
Bibliographic record
Abstract
The drinking water distribution system simulator (DSS) from the U.S. EPA was operated with a direct cross-connection of 0.3% wastewater to system volume per day for 70 d. During the cross-connection, tap water, wastewater, and system discharge water were monitored to ensure that the wastewater cross-connection was the source of study organisms and that these organisms were present in the water column of the DSS. The effectiveness of free chlorine levels of 0, 1, 2, and 5 mg/L to inactivate microbes in biofilms on PVC and ductile iron coupons following a wastewater cross-connection was determined. A reduction in organisms occurred after 12 h for both non-chlorinated PVC and ductile iron coupons. This suggests that the study organisms were able to adhere to the biofilm, but were not able to remain in the biofilm. The study organisms were inactivated both in the biofilm and in the water column. Water column data showed that biofilm released culturable heterotrophs and endospores into the water column throughout the 72 h evaluation period at all chlorine levels evaluated. Key words: biofilm, chlorine, wastewater, drinking water, microorganisms, cross-connection.
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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 | 0.001 |
| 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".