Shegaw Fentaye Sisay, Sirak Robele Gari, A. Ambelu
{"title":"Solid waste management service chain and sanitation safety: a case study of existing practice in Addis Ababa, Ethiopia","authors":"Shegaw Fentaye Sisay, Sirak Robele Gari, A. Ambelu","doi":"10.3389/fenve.2024.1414669","DOIUrl":"https://doi.org/10.3389/fenve.2024.1414669","url":null,"abstract":"Poor sanitation safety in municipal solid waste management can cause environmental and public health problems. This is the case in Ethiopia, where the sanitation safety standards are low in the municipal solid waste management operations. Therefore, the sanitation safety practices along the solid waste management service chains in Addis Ababa, Ethiopia are poorly understood, and this research will contribute new insights for the scientific community and can also inform policies and the current solid waste management operations in Addis Ababa.This study evaluated the safety of sanitation practices in the solid waste management service chain using a community-based approach in Addis Ababa city from January to August 2023. We have interviewed 384 participants using a cluster-random sampling technique and collected data through direct observations and face-to-face interviews. The study employed descriptive statistics, factor analysis and multiple linear logistic regression to analyze the data.The findings of the study revealed significant variations in sanitation safety practices and risks among households during solid waste management. While 60% of households practiced solid waste segregation, only 15% of them followed safe segregation practices. The majority of households (85%) used unsafe segregation practices, such as mixing different types of waste and storing wet and dry waste together. Additionally, 85% of households used storage and transport containers that had leaks, potentially leading to contamination and infection. Furthermore, the study identified sanitation safety risks and practices at waste collection and transport sites. The risks included solid waste droppings during transport, inadequate vehicle cleaning and disinfection, lack of personal protective equipment (PPE) for workers, and uncovered waste collection vehicles, leading to environmental contamination. At transfer stations, the study found several risk factors, such as the lack of protection from animals and human activities, absence of shower facilities for workers, and inadequate storage facilities for PPE and tools. The transfer stations also lacked odor-neutralizing systems, proper waste handling practices, and physical fly barriers. Workers did not have the opportunity to shower after work, further increasing the risk. The sanitation safety practices and risks at solid waste treatment/disposal sites were also assessed. The study revealed medium risks associated with waste treatment/disposal operations, including working without PPE, handling contaminated containers and raw waste, and releasing airborne particulates that could be inhaled by workers or the nearby community. Factor analysis was conducted to categorize the variables related to sanitation safety practices. Six factors were identified, explaining approximately 60.6% of the overall variance. These factors represented different aspects of sanitation safety, including onsite waste handling practices, failure to m","PeriodicalId":487591,"journal":{"name":"Frontiers in Environmental Engineering","volume":"16 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Francesca Cecconi, Leah Pifer, Fabrizio Sabba, Leon Downing
{"title":"Improving carbon management through maximizing hydrolysis and fermentation at water resource recovery facilities","authors":"Francesca Cecconi, Leah Pifer, Fabrizio Sabba, Leon Downing","doi":"10.3389/fenve.2024.1378621","DOIUrl":"https://doi.org/10.3389/fenve.2024.1378621","url":null,"abstract":"Wastewater treatment plants are transitioning from a sole focus on treatment objectives to integrated resource recovery and upcycling. Effective carbon management is critical for upcycling within a water resource recovery facility (WRRF) to produce energy or other usable products, which involves carbon diversion at primary treatment and waste activated sludge (WAS) from biological treatment processes. Many WRRFs are also driven to meet stringent effluent nutrient discharge targets while minimizing energy usage and chemical addition. Nutrient removal systems still rely on biodegradable organic carbon to support denitrification and enhanced biological phosphorus removal (EBPR). Biological nutrient removal not only requires sufficient organic substrate, but also the right type of bioavailable carbon for optimal utilization. The main objective of this pilot fermentation testing was to evaluate the most effective utilization of the range of organic-carbon rich feedstocks within a WRRF. Preliminary results suggest that a 50–50 blend of primary sludge (PS) and return activated sludge (RAS) fermentation leads to highest volatile fatty acid (VFA) yield. PS fermentation resulted in the minimum nutrients release per unit of volatile suspended solids (VSS), which makes it a best suited for biological nutrients removal WRRFs with stringent nitrogen (N) and phosphorus (P) limits. The volatile fatty acids fractions produced from different combinations of RAS and PS can impact the most suitable end use for each sludge type fermentation. PS resulted into higher levels of propionate, which are ideal for selecting phosphate accumulating organisms (PAO) over glycogen-accumulating organisms (GAO). On the other hand, for denitrification, acetate is the preferred substrate, which was most abundant with RAS only fermentation. Our research outcomes will be of value to utilities aiming to integrate the stringent effluent nutrient (N and P) discharge targets with energy and resource recovery.","PeriodicalId":487591,"journal":{"name":"Frontiers in Environmental Engineering","volume":"20 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141105044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Anaerobic biodegradation of brown grease and its potential as a source of renewable energy","authors":"Amy Heindel, Ross Lee, Dan Spracklin, Metin Duran","doi":"10.3389/fenve.2024.1354582","DOIUrl":"https://doi.org/10.3389/fenve.2024.1354582","url":null,"abstract":"The purpose of the study was twofold. The first was to study the anaerobic digestibility and the biochemical methane potential (BMP) of brown grease (BG)–fats and oils collected from restaurants and similar food production facilities. The second objective was to investigate the effects of adding dry, food waste derived hydrochar to enhance the digestion process, specifically as a possible in situ agent to improve biogas quality. The BMP tests involved various BG loadings between 3 and 30 g BG/L. The results indicate that BG is highly digestible under anaerobic conditions with 354 mL CH4/g COD equivalent of BG at 1 atm and 35°C testing conditions, which translates into 28 million gasoline gallon equivalent (GGE) potential energy that could be recovered by anaerobically digesting or co-digesting BG. The particular hydrochar investigated in this study did not show any potential to increase biogas CH4 content.","PeriodicalId":487591,"journal":{"name":"Frontiers in Environmental Engineering","volume":"27 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140229791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}