Modification of the Aeration-Supplied Configuration in the Biodrying Process for Refuse-Derived Fuel (RDF) Production

Biodrying is an essential part of the mechanical–biological treatment process that minimizes moisture content and simultaneously maximizes heating value for refuse-derived fuel (RDF) production. Although the mechanical separation process operates effectively in Thailand's RDF production, high organic content levels and their degradation cause moisture contamination in RDF, producing wet RDF. Aeration is essential for an effective biodrying process, and can reduce RDF's moisture content as well as increase its heating value. To maximize the biodrying effect, aeration should be optimized based on the waste conditions. This study proposes a modified aeration-supplied configuration for wet RDF biodrying. The aeration rate was modified based on the period within the biodrying operation;the first period is from the beginning until day 2.5, and the second period is from day 2.5 to day 5. The optimal aeration supply configuration was 0.5 m3/kg/day in the first period and then 0.3 m3/kg/day until the end of the process;this configuration yielded the greatest moisture content decrease of 35% and increased the low heating value of the biodried product by 11%. The final moisture content and low heating value were 24.07% and 4787 kcal/kg, respectively. Therefore, this optimal aeration-supplied configuration could be applied to meet the moisture content and low heating value requirements of the RDF production standard for Thailand's local cement industry.

Copper Leachability from Cu Nanoparticle-Containing Face Masks and Associated Subcellular Impacts

As a consequence of the COVID-19 pandemic, billions of people wear face masks for hours on a daily basis. However, whether hazardous materials released from the face masks might pose potential risks to human health remains mostly unexplored. In particular, nanoparticle-containing face masks have become popular in the market due to their improved antiviral and antibacterial effects. The leachability of nanoparticles and any subsequent toxicity are largely unknown. This study is the first to evaluate the Cu leachability from a face mask containing Cu nanoparticles and the subsequent cytotoxicity of the leachate. We showed that ∼20 μg of Cu in the mask was inhaled, accounting for almost 3% of the total Cu. Moreover, 30-40% of the Cu attached to fibers from the mask could be easily released into solution, and most of the released Cu existed in ionic forms. Cell-based testing indicated that although the leachate did not induce any cytotoxicity, it caused significant Cu stress leading to the exocytosis of lysosomes, changes in glutathione concentration, and the generation of reactive oxygen species. Overall, our results suggest that the leachability of nanoparticle-containing face masks should be carefully assessed, especially considering that most nanoparticle-containing face masks are recommended to be reusable after being washed. © 2023 American Chemical Society.

Per- and Polyfluoroalkyl Substances (PFAS) in Facemasks: Potential Source of Human Exposure to PFAS with Implications for Disposal to Landfills

Facemasks are important tools for fighting against disease spread, including Covid-19 and its variants, and some may be treated with per- and polyfluoroalkyl substances (PFAS). Nine facemasks over a range of prices were analyzed for total fluorine and PFAS. The PFAS compositions of the masks were then used to estimate exposure and the mass of PFAS discharged to landfill leachate. Fluorine from PFAS accounted only for a small fraction of total fluorine. Homologous series of linear perfluoroalkyl carboxylates and the 6:2 fluorotelomer alcohol indicated a fluorotelomer origin. Inhalation was estimated to be the dominant exposure route (40%-50%), followed by incidental ingestion (15%-40%) and dermal (11%-20%). Exposure and risk estimates were higher for children than adults, and high physical activity substantially increased inhalation exposure. These preliminary findings indicate that wearing masks treated with high levels of PFAS for extended periods of time can be a notable source of exposure and have the potential to pose a health risk. Despite modeled annual disposal of 29-91 billion masks, and an assuming 100% leaching of individual PFAS into landfill leachate, mask disposal would contribute only an additional 6% of annual PFAS mass loads and less than 11 kg of PFAS discharged to U.S. wastewater. © 2022 American Chemical Society.

Transformation of Solid Waste Management in China: Moving towards Sustainability through Digitalization-Based Circular Economy

In China, environmental pollution due to municipal solid waste (MSW) over-generation is one of the country’s priority concerns. The increasing volume and complexity of the waste poses serious risks to the environment and public health. Currently, the annual growth of MSW generation is estimated to be approximately 8–10% and will increase to 323 million metric tons (Mt) by 2030. Based on the secondary data collected from a literature survey, this article critically evaluates the recent progress of MSW management (MSWM) in China and offers new insights into the waste sector in the era of Industry 4.0. This helps decision makers in China to plan a smooth transition nationwide to a circular economy (CE) in the waste sector. It is evident that digitalization is a driving force for China to move towards low-carbon development strategies within the framework of CE. Through digitalization, the waste sector has promoted prevention, reduction, reuse, and recycling (3Rs) of waste before waste disposal in landfills. A proper implementation of digitalization-based waste recycling has contributed to an efficient cooperation between the government and private sector, increased job opportunities, and promoted the conservation of resources. It is anticipated that this work not only contributes to the establishment of an integrated MSWM system in China, but also improves local MSWM through digitalization in the framework of a CE.

First case of SARS-CoV-2 RNA detection in municipal solid waste leachate from Brazil.

This work presents the first case of SARS-CoV-2 RNA detection in leachate collected from a transfer station in the city of São Paulo, Brazil. After calibration of the viral detection method already used for wastewater samples with a pilot leachate sample and virus fragments in laboratory, twelve polyethylene glycol concentrated leachates samples were tested by RT-qPCR. The results confirmed the presence of N1 gene in 9 of the 12 analyzed samples between epidemiological weeks 33 and 38 of the year 2021 (08/15/2021 to 09/19/2021). The occurrence of the N2 gene was only observed in 5 of the 12 samples. The concentration values for N1 and N2 genes varied between 3.1 and 4.6 log10.GC·L-1, which are values close to those measured in sanitary wastewater. This method showed to be a promising procedure to verify the presence of viral RNA in municipal solid waste leachate, being especially useful where there is no treatment system and sanitation infrastructure, which makes the conventional wastewater surveillance unfeasible.

Proposal of an Initial Environmental Management and Land Use for Critical Cemeteries in Central Ecuador

Cemeteries are sites for the final disposal of human bodies that constitute a source of contamination of soil and water as a result of the cadaveric decomposition generated. The current research performed an initial study on the contamination of soil and water due to the influence of cemeteries and verified compliance with the legislation regulating land use and occupation of Central Ecuador (PUGS) with the aim of proposing an environmental and territorial solution to the problems generated by the mismanagement of cemeteries, through the physicochemical analysis of soil and water and studies of land use compatibility. The results indicate the tendency of contamination caused by the studied cemeteries, since the samples taken in both the rainy and dry season for the measurement of parameters BOD5, COD, DO, pH and electrical conductivity fail to meet the established requirements of the Ecuadorian and international environmental regulations. In addition, land use conflicts were encountered in the cemetery grounds. It is concluded that the existing cemeteries should be subjected to more detailed environmental analysis and subsequently should be treated as security landfills in the closure and post-closure stage. Also, it has been concluded that the cemeteries should not be located in urban or peri-urban areas.

SARS-CoV-2 and other pathogens could be determined in liquid samples from soils.

In the current COVID-19 pandemic, SARS-CoV-2 has been quantified in wastewater in various countries, and wastewater based epidemiology has been proposed as a potential early warning tool for new outbreaks. However, even taking into account that poorly treated wastewater and sewage sludge may be spread on soils, there is no published paper dealing with the quantification of the virus in soil-related liquid samples, as could be runoff, leachates, or soil solution. To fill this gap, the authors of this piece propose reflections on the development of a methodological approach for the quantification of SARS-CoV-2 (and eventually other pathogens) in soil-related liquid samples.