Impact of Landfill Gas Exposure on Vegetation in Engineered Landfill Biocover Systems Implemented to Minimize Fugitive Methane Emissions from Landfills.

Engineered landfill biocovers (LBCs) minimize the escape of methane into the atmosphere through biological oxidation. Vegetation plays a crucial role in LBCs and can suffer from hypoxia caused by the displacement of root-zone oxygen due to landfill gas and competition for oxygen with methanotrophic bacteria. To investigate the impact of methane gas on vegetation growth, we conducted an outdoor experiment using eight vegetated flow-through columns filled with a 45 cm mixture of 70% topsoil and 30% compost, planted with three types of vegetation: native grass blend, Japanese millet, and alfalfa.

The Impact of COVID-19 on Waste Infrastructure: Lessons Learned and Opportunities for a Sustainable Future.

The onset of the COVID-19 pandemic posed many global challenges, mainly in the healthcare sector; however, the impacts on other vital sectors cannot be overlooked. The waste sector was one of the significantly impacted sectors during the pandemic, as it dramatically changed the dynamics of waste generation. Inadequate waste management practices during COVID-19 shed light on the opportunities for developing systematic, sustainable, and resilient waste infrastructure in the future.

The influence of biochar and compost mixtures, water content, and gas flow rate, on the continuous adsorption of methane in a fixed bed column.

Biofiltration is an excellent alternative for the treatment of diffuse emissions of methane (CH) that cannot be treated by physical/chemical means or recovered for energy. Despite the advances on CH biological treatment technologies, they are limited by the low aqueous solubility of CH into the biofilm where CH mineralization occurs. In this study, the CH adsorption kinetics, adsorption capacity and transport behavior of CH was studied in batch experiments and in a fixed-bed column by varying the biochar and compost mixtures under 5-levels, 3 different water contents (dry, 15% and 30% water holding capacity), and 2 inlet flow rates.

Biofiltration of methane.

The on-going annual increase in global methane (CH) emissions can be largely attributed to anthropogenic activities. However, as more than half of these emissions are diffuse and possess a concentration less than 3% (v/v), physical-chemical treatments are inefficient as an abatement technology. In this regard, biotechnologies, such as biofiltration using methane-oxidizing bacteria, or methanotrophs, are a cost-effective and efficient means of combating diffuse CH emissions.

Biofiltration of methane using hybrid mixtures of biochar, lava rock and compost.

Using hybrid packing materials in biofiltration systems takes advantage of both the inorganic and organic properties offered by the medium including structural stability and a source of available nutrients, respectively. In this study, hybrid mixtures of compost with either lava rock or biochar in four different mixture ratios were compared against 100% compost in a methane biofilter with active aeration at two ports along the height of the biofilter. Biochar outperformed lava rock as a packing material by providing the added benefit of participating in sorption reactions with CH.

Aerated biofilters with multiple-level air injection configurations to enhance biological treatment of methane emissions.

Aiming to improve conventional methane biofilter performance, a multiple-level aeration biofilter design is proposed. Laboratory flow-through column experiments were conducted to evaluate three actively-aerated methane biofilter configurations. Columns were aerated at one, two, and three levels of the bed depth, with air introduced at flow rates calculated from methane oxidation reaction stoichiometry.

Rapid assessment of methanotrophic capacity of compost-based materials considering the effects of air-filled porosity, water content and dissolved organic carbon.

Since the global warming potential of CH4 is 25 times that of CO2 on a 100-year time horizon, the development of methanotrophic applications for the conversion of CH4 to CO2 is emerging as an area of interest for researchers and practicing engineers. Compost exhibits most of the characteristics required for methanotroph growth media and has been used in several projects. This paper presents results from a study that was undertaken to assess the influence of physical and chemical characteristics of compost-based materials on the biological oxidation of CH4 when used in methane biofilters.

Field-scale operation of methane biofiltration systems to mitigate point source methane emissions.

Methane biofiltration (MBF) is a novel low-cost technique for reducing low volume point source emissions of methane (CH₄). MBF uses a granular medium, such as soil or compost, to support the growth of methanotrophic bacteria responsible for converting CH₄ to carbon dioxide (CO₂) and water (H₂O). A field research program was undertaken to evaluate the potential to treat low volume point source engineered CH₄ emissions using an MBF at a natural gas monitoring station.

Effects of gas and moisture on modeling of bioreactor landfill settlement.

This manuscript describes a model that can predict settlement at variable moisture and pressure conditions as encountered in bioreactor landfills. In this model mechanical compression of municipal solid waste (MSW) was accounted with the help of laboratory compression tests. To model biodegradation-induced settlement, biodegradation of MSW was assumed to obey a first order decay equation.

Methane balance of a bioreactor landfill in Latin America.

This paper presents results from a methane (CH4) gas emission characterization survey conducted at the Loma Los Colorados landfill located 60 km from Santiago, Chile. The landfill receives approximately 1 million metric tons (t) of waste annually, and is equipped with leachate control systems and landfill gas collection systems. The collected leachate is recirculated to enable operation of the landfill as a bioreactor.

Study of thin biocovers (TBC) for oxidizing uncaptured methane emissions in bioreactor landfills.

Bioreactor landfills are designed to accelerate municipal solid waste biodegradation and stabilization; however, the uncaptured methane gas escapes to the atmosphere during their filling. This research investigates the implementation of a novel methane emission control technique that involves thin biocovers (TBC) placed as intermediate waste covers to oxidize methane without affecting the operation of bioreactor landfills. Batch incubation experiments were conducted for selecting the optimum TBC materials, capable of oxidizing methane to carbon dioxide by methanotrophic bacteria.

Evaluation of TENORMs field measurement with actual activity concentration in contaminated soil matrices.

The occurrence of technologically enhanced naturally occurring radioactive materials (TENORMs) concentrated through anthropogenic processes in contaminated soils at oil and gas facilities represent one of the most challenging issues facing the Canadian and US oil and gas industry today. Natural occurring radioactivity materials (NORMs) field survey techniques are widely used as a rapid and cost-effective method for ascertaining NORMs risks associated with contaminated soils and waste matrices as well other components comprising the environment. Because of potentially significant liability issues with Norms if not properly managed, the development of quantitative relationships between TENORMs field measurement techniques and laboratory analysis present a practical approach in facilitating the interim safe decision process since laboratory results can take days.

WITHDRAWN: Study of thin biocovers (TBC) for oxidizing uncaptured methane emissions in bioreactor landfills.

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Waste Management, volume 28 (2008) 1364 - 1374, doi:10.1016/j.wasman.

Relation of waste generation and composition to socio-economic factors: a case study.

To develop an effective waste management strategy for a given region, it is important to know the amount of waste generated and the composition of the waste stream. Past research has shown that the amount of waste generated is proportional to the population and the average mean living standards or the average income of the people. In addition, other factors may affect the amount and composition of waste.

Numerical model to predict settlements coupled with landfill gas pressure in bioreactor landfills.

Landfills settle due to its weight and biodegradation of waste. Biodegradation-induced settlement is a direct result of rearrangement of waste skeleton in response to the conversion of waste mass into landfill gases. Traditionally, the compressibility index based on settlement of clays is used to explain the settlement of waste.