Journal of the Air & Waste Management Association最新文献

Human activities have increased atmospheric emissions and deposition of oxidized and reduced forms of nitrogen, but emission control programs have largely focused on oxidized nitrogen. As a result, in many regions of the world emissions of oxidized nitrogen are decreasing while emissions of reduced nitrogen are increasing. Emissions of reduced nitrogen largely originate from livestock waste and fertilizer application, with contributions from transportation sources in urban areas. Observations suggest a discrepancy between trends in emissions and deposition of reduced nitrogen in the U.S., likely due to an underestimate in emissions. In the atmosphere, ammonia reacts with oxides of sulfur and nitrogen to form fine particulate matter that impairs health and visibility and affects climate forcings. Recent reductions in emissions of sulfur and nitrogen oxides have limited partitioning with ammonia, decreasing long-range transport. Continuing research is needed to improve understanding of how shifting emissions alter formation of secondary particulates and patterns of transport and deposition of reactive nitrogen. Satellite remote sensing has potential for monitoring atmospheric concentrations and emissions of ammonia, but there remains a need to maintain and strengthen ground-based measurements and continue development of chemical transport models. Elevated nitrogen deposition has decreased plant and soil microbial biodiversity and altered the biogeochemical function of terrestrial, freshwater, and coastal ecosystems. Further study is needed on differential effects of oxidized versus reduced nitrogen and pathways and timescales of ecosystem recovery from elevated nitrogen deposition. Decreases in deposition of reduced nitrogen could alleviate exceedances of critical loads for terrestrial and freshwater indicators in many U.S. areas. The U.S. Environmental Protection Agency should consider using critical loads as a basis for setting standards to protect public welfare and ecosystems. The U.S. and other countries might look to European experience for approaches to control emissions of reduced nitrogen from agricultural and transportation sectors.Implications: In this Critical Review we synthesize research on effects, air emissions, environmental transformations, and management of reduced forms of nitrogen. Emissions of reduced nitrogen affect human health, the structure and function of ecosystems, and climatic forcings. While emissions of oxidized forms of nitrogen are regulated in the U.S., controls on reduced forms are largely absent. Decreases in emissions of sulfur and nitrogen oxides coupled with increases in ammonia are shifting the gas-particle partitioning of ammonia and decreasing long-range atmospheric transport of reduced nitrogen. Effort is needed to understand, monitor, and manage emissions of reduced nitrogen in a changing environment.

As a traditional method of waste treatment, municipal solid waste incineration (MSWI) has become one of the main methods of urban waste treatment. However, as a byproduct of MSWI, a large amount of MSWI bottom ash is not reused in current practice. This study innovatively posits MSWI bottom ash as an eco-friendly adsorbent rather than a pollutant, exploring its potential application as a permeable subgrade material. The results reveal that MSWI bottom ash exhibits promising properties to serve as a permeable subgrade material to achieve the permeability and improve the sustainability for subgrade. Due to the arrangement of its particles, it shows excellent performance in shear strength and permeability, which are comparable to or surpass those of sandy soils. The average pore width of 14.200 nm allows heavy metal substances to be encapsulated within the matrix, significantly reducing their leachability, thereby aligning with environmental friendliness standards. Its adsorption capacity is about 6.60 mg/g, and the adsorption capacity per volume is 3.66 times and 2.04 times that of fly ash and clay, respectively. The mechanism analysis shows that the adsorption process is monolayer heterogeneous adsorption. This paper presents a novel perspective on reusing MSWI bottom ash and provides evidence supporting its effective utilization as a permeable subgrade material, offering substantial environmental benefits through enhanced adsorption ability.Implications: Municipal solid waste incineration (MSWI) is a common method for municipal solid waste treatment, while the MSWI bottom ash is often not reused. This paper explored the explores the feasibility of using MSWI bottom ash as a permeable road base material. The results show that the particle arrangement enables excellent shear strength and permeability, comparable to sandy soil. It meets safety requirements for the leaching of heavy metals and acts as an adsorbent for pollutants leaching from permeable pavements. Furthermore, the mechanisms underlying these behaviors of MSWI were confirmed by microstructural and mineralogical analyses. These indicate that MSWI bottom ash has great potential as a permeable road base material. This paper provides a clear understanding of the physical, mechanical and environmental properties of MSWI bottom ash, which can promote its reuse in practice.

Economic growth has a potential impact on waste generation worldwide. Growing recognition for resources recovery from waste including production of a clean energy has led to the development of standards for, and the generation of, Solid Recovered Fuel (SRF). SRF, according to BS EN ISO 21640 is a fuel prepared from nonhazardous/treated waste to be utilized for energy recovery in incineration or co-incineration plants which meets the classification and specification. The amount of combustible fractions (i.e., plastic, textile and paper) that are present in Healthcare Waste (HCW) and Municipal Solid Waste (MSW) provides an opportunity for SRF production. HCW is defined as clinical waste generated from healthcare facilities. Limited efforts in utilizing treated HCW in production of SRF were noted, despite the fact that high content of combustible fractions, hence the novelty of this research. This research addresses the opportunities of utilizing autoclaved HCW as an alternate fuel; through a detailed chemical and physical analysis of autoclaved HCW collected from the Sultanate of Oman hospital and healthcare facilities. Furthermore, this study examines the possible uses of such materials instead of landfilling. The utilization of treated HCW as an alternative fuel is not only saving the land space, but also reduces the carbon emissions originating from landfilling. This in fact would also support the government in achieving its aspiring goal of the net zero carbon emissions by 2050 through better utilization of these materials in production of SRF as an alternative to fossil fuel combustion. The study revealed that autoclaved HCW appears to have a high quality SRF and is classified as (NCV 4, Cl 3); which complies with the potential end users' specifications. It is estimated that the combined energy output from MSW and HCW combustible fractions could cover about 12.75% of the energy requirements for Oman cement factories.Implications: The results confirm the viability of using autoclave (HCW) as an alternative fuel due to its high thermal energy content. Based on mean Net Calorific Value (NCV) of analyzed HCW that is found around 14 (MJ/Kg _(ar)), and the mean Cl level (i.e., 0.814 ± 0.213% _(d)); the SRF is classified as (NCV4, Cl 3). This grade is found to be well within the end users accepted range. This opens up the opportunity for creating a market demand for HCW that not only it could boost its recovery, but it could also unlock the value that can generates.

Globally, particulate matter with an aerodynamic diameter of 2.5 µm or less poses a significant threat to human health. The first step in quantifying human health impacts caused by exposure to PM_2.5 pollution is exposure assessment. Population-weighted exposure level (PWEL) estimation is one of the methods that provides a more precise exposure assessment since it incorporates the spatiotemporal distribution of population with the pollution concentration estimate. In this study, PM_2.5 exposure levels in the local communities around brickmaking industries were investigated, using the population census data of the study area and 1-year data from nine PM_2.5 monitoring stations installed in and around the brickmaking industries. The observed PM_2.5 data was spatially interpolated using inverse distance weight (IDW). Data on PM_2.5 levels across the study area were classified based on the World Health Organization interim target (IT) guidelines and the South African National ambient air quality standard (NAAQS). An annual PM_2.5 population weighted exposure level of 27.6 µg/m³ was estimated for the study area. However, seasonal exposure levels of 28.9, 37.6, 26.5, and 20.7 µg/m³ were estimated for the autumn, winter, spring, and summer seasons, respectively. This implies that local communities around the brick kiln in the Vhembe District are exposed to high levels of PM_2.5, especially in winter. The PM_2.5 levels in the brickmaking industries as well as its other sources in the Vhembe District, therefore, need to be lowered. Findings from population exposure level to pollutants can provide valuable data for formulating policies and recommendations on exposure reduction and public health protection.Implications: PM_2.5 concentration in any given environment has high spatial and temporal variability due to the presence of diffused sources in the environment. Using ambient air concentrations to directly estimate population exposure without taking into consideration the disproportionate spatial and temporal distribution of the pollutant and the population may not yield accurate results on human exposure levels. It is, therefore, important to assess the aggregated PM_2.5 exposure of a populace within a given area. This study therefore examines the PM_2.5 population-weighted-exposure level of the host communities of the brickmaking industry in Vhembe District, South Africa.

Mid-wavelength infrared (MWIR) imaging Fourier transform spectrometers (IFTSs) are a promising technology for measuring flare combustion efficiency (CE) and destruction removal efficiency (DRE). These devices generate spectrally resolved intensity images of the flare plume, which may then be used to infer column densities of relevant species along each pixel line-of-sight. In parallel, a 2D projected velocity field may be inferred from the apparent motion of flow features between successive images. Finally, the column densities and velocity field are combined to estimate the mass flow rates for the species needed to calculate the CE or DRE. Since the MWIR IFTS can measure key carbon-containing species in the flare plume, it is possible to measure CE without knowing the fuel flow rate, which is important for fenceline measurements. This work demonstrates this approach on a laboratory heated vent, and then deploys the technique on two working flares: a combustor burning natural gas at a known rate, and a steam-assisted flare at a petrochemical refinery. Analysis of the IFTS data highlights the potential of this approach, but also areas for future development to transform this approach into a reliable technique for quantifying flare emissions.Implications: Our research is motivated by the need to assess hydrocarbon emissions from flaring, which is a critical problem of global significance. For example, recent studies have shown that methane destruction efficiency of flaring from upstream oil may be significantly lower than the commonly assumed figure of 98%; work by Plant et al. , in particular, suggest that this discrepancy amounts to CO₂ emissions from 2 to 8 million automobiles annually, considering the US alone. Similarly, the international energy agency (IEA) estimates a global flare efficiency of 92%, which translates in 8 million tons of CH₄ emitted by flares in 2020. Highlighted by these studies and supported by the World Bank initiatives toward zero routine flaring emissions, there is an urgent need for oil and gas industry to assess their flare methane emission, and overall hydrocarbon emissions. At the very least, it is critical to identify problematic flare operating conditions and means to mitigate flare emissions. Focusing on remote quantification of plume species, the measurement technique and quantification method presented in this paper is a considerable step forward in that direction by computing combustion efficiency and key components for destruction efficiency.

The lower mainland of British Columbia is a geographic region that comprises the districts of Metro Vancouver and the Lower Fraser Valley. It is situated in a complex topographical and coastal location in southwestern British Columbia. Metro Vancouver is Canada's third largest population center. Accessing the Canadian National Air Pollution Surveillance Program (NAPS) database we calculated air pollutant statistics using the Canadian Ambient Air Quality Standards (CAAQS) averaging times, numerical forms, and numerical levels for the years 2001to 2020. Man Kendall and Sen statistical methods were used to test for the presence of trends and the slope of those trends in fine particulate matter (PM_2.5), ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and volatile organic compound (VOC) ambient air concentrations. We did not determine a significant trend in 98^th percentile of the daily 24-hr average PM_2.5 concentrations. We did determine significant negative trends in the annual average of the daily 24-hr average PM_2.5 concentrations at 6 of the 9 locations. Episodic, multi-day duration elevated PM_2.5 concentrations related to forest fires were a significant influence on PM_2.5 ambient concentrations. Annual 4^th highest daily maximum 8-hr average O₃ concentrations showed no trend at 14 of 18 locations, declined at 3 locations, and increased at one location. We determined statistically significant declines in peak and average NO₂ and SO₂ concentrations, and in time-integrated annual VOC concentrations.Implications: This non-parametric, statistical analysis determines 20-year trends in British Columbia lower mainland ambient air quality for PM_2.5, O₃, NO₂, SO₂ and VOC, assesses air quality against Canadian Ambient Air Quality Standards, and highlights the importance of event-based wildfire-sourced PM_2.5.

Water-based paint sludge generated from the automotive industry is considered a hazardous waste due to its high carbon content and is challenging and costly to manage. This study investigates the management of water-based paint sludge through the composting process, considering its high carbon content. The water-based paint sludge was composted in five separate reactors with the addition of treatment sludge from the same industry as co-substrate and inoculum, as well as sunflower stalks as a bulking agent. The ratio of paint sludge added to the compost mixtures varied between 40% and 80%. The highest temperature was achieved in reactors where industrial sludge was added, and the bulking agent was used at a rate of 20% (R3 and R5). The most efficient composting process was conducted with the addition of 60% water-based paint sludge, 20% treatment sludge, and 20% sunflower stalks (w/w, wet weight basis) (R3). During this process, reductions in organic matter content were observed due to organic matter mineralization, resulting in a decrease in moisture during the maturation phase and consequently reducing waste volumes. The composting process can be a useful tool in addressing the challenges of paint sludge management. Utilizing the composting process not only reduces waste volumes, thereby minimizing environmental impacts, but also offers a sustainable approach to paint sludge management by lowering disposal costs. It is also possible to achieve more effective results by composting paint sludge with different recipes and the use of various bulking agents.Implications: Composting is a method that can be used to achieve stabilization, reduce the quantity, and enable biodrying of water-based paint sludge generated from the automotive industry. In this study, different ratios of paint sludge were mixed with treatment sludge from the same industry as co-substrate and inoculum, while sunflower stalks were added as a bulking agent, and a composting process was conducted. The addition of industrial wastewater treatment sludge and sunflower stalks has increased the efficiency of the paint sludge composting process. In the management of paint sludge, the composting process has emerged as a significant alternative that reduces disposal costs and environmental impacts.

In this study, biodegradable dust suppressants were prepared using glycerol and biomass-based oily compounds, including palm oil, biodiesel, and soybean oil. The suppressing ability of the glycerol and the oily compound mixture was evaluated using wind tunnel tests, and factors affecting the suppression of the particles were determined. The replacement of sodium dodecyl sulfate with coco glucoside and lauryl glucoside significantly enhanced the biodegradability of the suppressants (2.02 vs. 9.01 and 8.54 mg/L of BOD₅). The glycerol and soybean oil mixture exhibited excellent performance owing to the relatively high viscosity of the suppressants, and the optimal dilution ratio was 1:50 and 1:1000 for sand and granite-weathered soil, respectively. More than 98% of suppression was obtained under the optimal conditions. The effect of the particle properties (particularly permeability) was significant, even though the viscosity of the suppressants was responsible for the suppression of the particles. Our results suggest that the mixture of glycerol and biomass-based oily compounds could be a promising suppressant for reducing the mobility of ultrafine particles in the atmosphere.Implications: Since the early 2010s, anthropogenic fugitive dust from industrial activities has become a serious environmental issue due to its serious hazards to the environment and human health in South Korea. So far, several dust suppressants (mostly salts) were made and used for field application. However, due to their toxic effects, it is necessary to develop a new eco-friendly suppressant that can be biodegraded in the soil and that is not hazardous to human health or the environment. Previously we have developed an eco-friendly dust suppressant with low toxicity and high suppression ability using ingredients and by-products of biodiesel production, marine biomass, and commercial vegetable oils (Tsgot and Oh 2021, J. Air Waste Manag. Assoc. 71:1386-1396). However, due to the low biodegradability of surfactant, the synthesized dust suppressants showed limited biodegradability. As a follow-up to our previous study, we employed readily biodegradable surfactants as additives to enhance the biodegradability of the dust suppressants with the same excellent suppressing ability. To determine the optimal conditions, the synthesis and preparation of the dust suppressants was conducted using biodegradable surfactants, including coco glucoside and lauryl glucoside. The factors affecting the suppressing ability of the suppressants were examined via wind tunnel tests. These factors include the dilution factors, the viscosity of the suppressants, and the type of suppressed particles. Possible suppressing mechanisms were also discussed.