Effects of phosphorus addition on treatment efficiency of an anaerobic filter treating landfill leachate
Bibliographic record
Abstract
Sanitary landfill leachate is a source of environmental concern due to its high organic strength and chemical diversity. The widespread use of sanitary landfills has resulted in regulatory authorities requiring municipalities to give serious consideration to the treatment and safe disposal of this wastewater. A number of lab-scale and pilot scale studies have indicated that the anaerobic filter .is highly competitive with other forms of biological treatment and has distinct economic advantages. While there have been a number of studies based on a general overall approach to leachate treatment by the anaerobic filter, limited' information is available on the role played by essential nutrients (phosphorus and nitrogen) in the biological treatment process. Laboratory studies were conducted at room temperature (22°C) to study the effect of nutrient addition (specifically, phosphorus, the deficient constituent of most leachates) on treatment efficiency of landfill leachate by the upflow anaerobic filter. Two anaerobic filters (0.975 metres x 0.15 metres diameter) were constructed using plexiglass pipes and packed with strips of corrugated fibre-glass sheets in four layers to form the filter bed. Leachate collected from a nearby landfill was applied at moderate organic loadings (2.0-4.2 kg COD/m³.day) to the two units maintaining a HRT of 0.987 days. During runs 2 and 4, leachate collected from the Premier landfill had a very low organic strength, necessitating the addition of acetic acid to raise that strength to around 2000 mg/l COD. When phosphorus addition was made at the 10 mg/l level to this feed, no favourable effect on COD removal was observed, possibly because the feed was VFA based and not inclusive of complex organics. During run 3, the strength of the leachate increased to around 4000 mg/l, with a relatively lower proportion of the COD present as VFA (around 1600 mg/l as acetic acid). When phosphorus addition was made to this feed at a 40 mg/l level, COD removal capacity of the anaerobic filter improved significantly, indicating that phosphorus may be added to an organically diverse waste with distinct advantages.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 | 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".