Ozonation for the improvement of wastewater quality in lagoons
Bibliographic record
Abstract
Concerns over environmental sustainability in Canada have increased in recent years leading to changes to the discharge limits of certain contaminants like biological oxygen demand (25 mg/L), ammonia (1.25 mg NH3-N/L), and total suspended solids (25 mg/L) in effluent from wastewater treatment facilities collecting an average daily influent volume of 100 m 3 or more.Contaminants of emerging concern (CECs) like pharmaceuticals, hormones, pesticides, herbicides, and other natural and synthetic compounds found in effluent from wastewater treatment facilities remain unregulated in Canada but may persist in the environment and lead to negative environmental outcomes.Given the number of Canadians who rely upon lagoons for their wastewater treatment in small, rural, and remote communities, there is a need to investigate and develop new, cost-effective strategies to improve the quality of wastewater treated in lagoons.Ozonation has been shown to improve the removal of a variety of wastewater contaminants (including CECs) from real wastewater through direct means (oxidation of compounds) and indirect means (increased dissolved oxygen, enhanced biodegradability) and was investigated in the present thesis as a potential strategy to improve wastewater treatment in lagoons.Two pilot tests were conducted to investigate the effects of ozonation on contaminant removal in lagoons.Samples of wastewater were collected from several locations in each lagoon prior to ozonation, during ozonation, and after ozonation and analyzed to determine the effect of ozonation on the removal of conventional contaminants and CECs.The samples were analyzed for biological oxygen demand (BOD), chemical oxygen demand (COD), total ammonia, unionized ammonia, total dissolved solids (TDS), total suspended solids (TSS), nitrite, nitrate, toxicity to Vibrio fischeri, and for the presence of fifteen CECs. RésuméLes préoccupations environnementales au Canada ont augmenté au cours des dernières années, ce qui a entraîné des changements aux limites de rejet concernant la demande biochimique en oxygène (25 mg/L), de l'ammoniac (1,25 mg NH3-N), et des matières en suspension (25 mg/L) pour les effluent des stations de traitement dont le volume moyen quotidien est de 100 m 3 ou plus.Les contaminants d'intérêt émergent (CIE) comme les produits pharmaceutiques, les hormones, les pesticides, les herbicides et d'autres composés naturels et synthétiques présents dans les eaux usées ne sont pas réglementés au Canada.Ceux-ci peuvent persister dans l'environnement et entraîner des effets négatifs sur l'environnement.Étant donné le nombre de Canadiens qui dépendent d'étangs pour le traitement de leurs eaux usées, surtout dans les petites communautés rurales et éloignées, il est nécessaire d'étudier et de développer de nouvelles stratégies peu couteuses pour améliorer la qualité des eaux usées traitées dans ces étangs.Il a été démontré que l'ozonation améliore l'élimination d'une variété de contaminants (y compris les CIE) des eaux usées réelles par des moyens directs (oxydation des composés) et indirects (augmentation de l'oxygène dissous, biodégradabilité accrue) et a été étudiée dans la présente thèse comme une stratégie possible pour améliorer le traitement d'eau usée dans les étangs.Deux essais pilotes ont été réalisés pour étudier les effets de l'ozonation sur l'élimination des contaminants dans les étangs.Des échantillons d'eaux usées ont été prélevés à plusieurs endroits dans chaque étang avant, pendant et après l'ozonation et analysés pour déterminer l'effet de l'ozonation sur l'élimination des contaminants classiques et des CIE.Les échantillons ont été analysés pour la demande biochimique en oxygène (DBO), la demande chimique en oxygène (DCO), l'ammoniac total, l'ammoniac non ionisé, les matières dissous totales (MDT), les matières en suspension totales (MST), le nitrite, le nitrate, la toxicité envers Vibrio fischeri et la présence de quinze CIEs.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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".