Persistence of <i>Clostridium difficile</i> in wastewater treatment-derived biosolids during land application or windrow composting
Bibliographic record
Abstract
AIMS: To determine the persistence of Clostridium difficile spores in biosolids during composting or when amended into soil and held under natural environmental climatic conditions. METHODS AND RESULTS: Five log CFU g(-1) Cl. difficile spores (ribotypes 027 or 078) were inoculated into agricultural soils (sandy loam or loam) amended with 10% w/w anaerobically digested biosolids. The inoculated soil : biosolids mixture was then placed into sentinel vials which were introduced at a depth of 15 cm within the field plot consisting of the corresponding soil type. Two trials were performed, the first of which started in late spring (May 2013 through to August 2014) and second from November 2013 through to October 2014 (fall trial). Ribotype 078 endospores in loam or sandy loam soil decreased during the summer but then increased in numbers towards the fall. At the end of the trial, levels of ribotype 078 spores had decreased by 1·5 log CFU g(-1) , with 027 spores decreasing by <1 log CFU g(-1) over the same time period. Windrow composting of biosolids decreased Cl. difficile levels from 3·7 log CFU g(-1) down to 0·3 log CFU g(-1) with the greater reduction occurring during the curing phase. In comparison, Cl. perfringens decreased from 6·3 log CFU g(-1) down to 2·4 log CFU g(-1) but mainly in the thermal phase of the composting process. CONCLUSIONS: Composting of biosolids is a more effective means of inactivating Cl. difficile compared to land application. SIGNIFICANCE AND IMPACT OF THE STUDY: Windrow composting represents an effective method to reduce the environmental burden of Cl. difficile associated with biosolids.
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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 | 0.000 |
| 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 | 0.001 | 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".