Microbiome re-assembly boosts anaerobic digestion under volatile fatty acid inhibition: focusing on reactive oxygen species metabolism.

The accumulation of volatile fatty acids (VFAs) in anaerobic digestion (AD) systems resulting from food waste overload poses a risk of system collapse. However, limited understanding exists regarding the inhibitory mechanisms and effective strategies to address VFAs-induced stress. This study found that accumulated VFAs exert reactive oxygen species (ROS) stress on indigenous microbiota, particularly impacting methanogens due to their lower antioxidant capability compared to bacteria, which is supposed to be the primary reason for methanogenesis failure.

Mitigation of methane emissions from three Danish landfills using different biocover systems.

The establishment of biocover systems is an emerging methodology in reducing methane (CH) emissions from landfills. This study investigated the performance of three biocover systems with different designs (biowindow and passively and actively loaded biofilters) in mitigating CH emissions from three landfills in Denmark. A series of field tests were carried out to evaluate the functionality of each system, and total CH emissions from relevant landfill sections or the entire landfill were measured before and after biocover implementation.

Odorous gas emissions from sewage sludge composting windrows affected by the turning operation and associated health risks.

The treatment and disposal of sewage sludge (SL) has long been a challenging task in China. Open windrow composting, coupled with mechanical turning, is preferred in small cities and rural areas, due to low costs and ease of operation. However, the emission of odorous volatile organic compounds (VOCs) from open composting windrows, as well as related health risks, has aroused strong protests from surrounding populations.

Efficiency of gas collection systems at Danish landfills and implications for regulations.

Globally, landfills are an important source of anthropogenic methane emissions. Regulations require landfill gas be managed to reduce emissions, and some landfills have therefore installed gas collection systems to recover energy and mitigate methane emissions. However, the efficiency of such systems is seldom evaluated.

Mitigation of methane and trace gas emissions through a large-scale active biofilter system at Glatved landfill, Denmark.

Biocover systems are a cost-effective technology utilised to mitigate methane (CH) and trace gas emissions from landfills. A full-scale biofilter system was constructed at Glatved landfill, Denmark, consisting of three biofilters with a total area of 3950 m. Landfill gas collected mainly from shredder waste cells was mixed with ambient air and fed actively into the biofilter, resulting in an average load of 60-75 g m d for CH and 0.

Trace gas composition in landfill gas at Danish landfills receiving low-organic waste.

In 1997, the landfilling of biodegradable waste was banned in Denmark, and currently Danish landfills receive mostly non-combustible waste with a low-organic content. This study aimed to investigate trace gas composition in landfill gas (LFG) at modern Danish landfills. Landfill gas samples were taken from waste cells containing shredder, mixed and aged waste from four Danish landfills.

Improving the analytical flexibility of thermal desorption in determining unknown VOC samples by using re-collection.

The thermal desorption (TD) technique has long suffered from the 'one-shot' problem, whereby the entire sample is consumed in a single analysis, and thus no sample remains for repeated analysis. Recent developments in TD equipment allow for the quantitative re-collection of split samples during thermal desorption, which can be utilised for archiving or immediate analysis. However, the performance of TD systems for re-collecting different volatile organic compounds (VOCs) has rarely been demonstrated.

Trace gas emissions from municipal solid waste landfills: A review.

Trace gas emissions from municipal solid waste (MSW) landfills have received increasing attention in recent years. This paper reviews literature published between 1983 and 2019, focusing on (i) the origin and fate of trace gas in MSW landfills, (ii) sampling and analytical techniques, (iii) quantitative emission measurement techniques, (iv) concentration and surface emission rates of common trace compounds at different landfill units and (v) the environmental and health concerns associated with trace gas emissions from MSW landfills. Trace gases can be produced from waste degradation, direct volatilisation of chemicals in waste products or from conversions/reactions between other compounds.

Characteristics of volatile compound emission and odor pollution from municipal solid waste treating/disposal facilities of a city in Eastern China.

Transfer station, incineration plant, and landfill site made up the major parts of municipal solid waste disposal system of S city in Eastern China. Characteristics of volatile compounds (VCs) and odor pollution of each facility were investigated from a systematic perspective. Also major index related to odor pollution, i.

Volatile compounds emission and health risk assessment during composting of organic fraction of municipal solid waste.

Degradation of mechanically sorted organic fraction (MSOF) of municipal solid waste in composting facilities is among the major contributors of volatile compounds (VCs) generation and emission, causes nuisance problems and health risks on site as well as in the vicinages. The aim of current study was to determine the seasonal (summer and winter) variation and human health risk assessment of VCs in the ambient air of different processing units in MSOF at composting plant in China. Average concentration of VCs was 58.

Characterization of odor emission on the working face of landfill and establishing of odorous compounds index.

Temporal variation (seasonal and daily) of odor emission on the working face of a large sanitary landfill in China was characterized through a 2 yearlong case study. Odor pollution was most serious in spring and autumn, while lower odor concentrations were detected in summer and winter. The daily fluctuation of odor concentration on the working face showed that 2:00am, 6:00am, 2:00pm and 10:00pm were the "most probable times" for odor pollution occurrence, which deserves focused attention in odor control projects.

Effect of biocover equipped with a novel passive air diffusion system on microbial methane oxidation and community of methanotrophs.

A novel biocover with passive air diffusion system (PADS) was designed in this study. Its effect on landfill gas components in the macrocosms of simulated biocover systems was also investigated. The results show that O2 concentration increased in the whole profile of the macrocosms equipped with PADS.