Bibliographic record
Abstract
Throughout the world, wastewater and organic waste are increasingly being viewed as energy sources and the practice of converting them into bioenergy through conversion to biogas with anaerobic digestion is growing. This paper presents an overview of planning, research, and full-scale operations of both separate and codigestion of organic waste. Organic waste management methods are compared with respect to economic (life-cycle costs), environmental (equivalent carbon dioxide emissions), social, and operational impacts for a representative 100,000 population community. Management methods include using sewers or trucks to transport the organics to anaerobic digesters at a wastewater treatment plant, using a material recovery facility (MRF) to extract the organics from municipal solid waste for anaerobic digestion, composting the organic waste, or sending the organics to a landfill. Hauling the organics to anaerobic digesters had the lowest equivalent CO2 emissions, while using the sewer to convey organics had the lowest life-cycle cost. An example of codigestion of organic waste with wastewater sludge at the Des Moines Water Reclamation Facility (Iowa, USA) is described. The limits of organic loading rates for digestion of FOG (fats, oils, and grease) with wastewater sludge are presented based on research using 1,000-litre (L) pilot digesters. A specific energy loading rate (SELR) is proposed as an improved parameter for organic loading rates. The SELR is a measure of energy loading relative to the reactor biomass, and is an innovative approach to characterizing digester capacity and stability. Food wastes from the cafeteria at the U.S. Air Force Academy were digested in bench-scale, semi-continuous reactors and monitored using an online respirometer capable of continuously monitoring gas flow rate and gas composition. The biological methane potential (BMP) of several organic wastes were measured in lab-scale digesters. Organic wastes were digested with and without domestic wastewater sludge. Separate digestion of organic wastes was found to be nutrient (cobalt, nickel) deficient, where codigestion with wastewater sludge experienced no deficiencies. Codigestion could also handle a greater amount of FOG being fed to the digesters than separate digestion of food wastes.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.020 | 0.007 |
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".