The impact of natural and anthropogenic hydrocarbons on the tropospheric budget of carbon monoxide

A method to quantify the relative contributions of surface sources and photochemical production of atmospheric carbon monoxide has been implemented in a three-dimensional chemical-transport model. The impact of biogenic and anthropogenic hydrocarbons has been calculated. The oxidation of isoprene contributes to about 10% of the global tropospheric burden of carbon monoxide, with a maximum contribution over southern America and Africa. Oxidation of methane and terpenes contribute to 28 and 2%, respectively, of the tropospheric burden of CO. The oxidation of the other hydrocarbons, which include ethane, propane, ethylene, propylene and the surrogate hydrocarbon representing other hydrocarbons results in 12% of the CO tropospheric burden, among which 69% results from the oxidation of hydrocarbons of biologic origin. The overall global CO yield from the oxidation of isoprene is estimated to be 23% on a carbon basis. Comparisons between model results and the few available observations of isoprene, terpenes and their oxidation products show that there is no evidence that the current global isoprene emissions proposed in the IGAC/GEIA emissions data base are substantially overestimated, as suggested by previous studies.     

Air Pollutant Emissions from the Incineration of Hospital Wastes The Alberta Experience

Since the early seventies, hospital waste incineration has been an ever increasing issue in Alberta because of the emissions of particles, hydrochloric acid and chlorine which result from burning plastic-rich hospital waste. These stack emissions were measured from various hospital incinerators in the Province of Alberta and most were found to be above the standards adopted by the Alberta Department of Environment. Compliance with particulate and HC1 emission standards are mandatory in order to receive final approval for a hospital incinerator in Alberta. Adequate control measures are available to meet Alberta Environment requirements for hospital incinerator emissions.     

SGA对垃圾焚烧飞灰中重金属的固化性能研究简

根据EPA 1311、HJ/T 299-2007、HJ/T 300-2007和HJ 557-2009等国内外不同标准，研究了深圳某垃圾焚烧发电厂垃圾焚烧飞灰的浸出毒性，探讨了六硫代胍基甲酸（sixthio guanidine acid，SGA）、二甲基二硫代氨基甲酸盐（sodium dimethyl dithio carbamate，SDD）和Ca（OH）₂浓度对垃圾焚烧飞灰中重金属的固定性能的影响。研究结果表明，随着浸提液pH的降低，该厂焚烧飞灰中大部分金属元素的浸出量增大，焚烧飞灰浸出液中的Cd、Ni、Pb和Zn浓度分别超过国家危险废物鉴别标准（GB5085.3-2007）规定值的4.75倍、1.47倍、6.72倍和2.20倍，属于危险废弃物，必须进行稳定化处理。当固化剂SGA加入量为0.1 mol/kg时，稳定化后的重金属浸出浓度已经低于危险废物鉴别标准，且对Cd、Cr、Cu和Pb的固化性能优于SDD和Ca（OH）₂；当固化剂SGA、SDD和Ca（OH）₂加入量为0.5 mol/kg时，稳定化后的焚烧飞灰重金属浸出浓度均低于国家危险废物鉴别标准（GB 5085.3-2007）中的规定值。与SDD和Ca（OH）₂相比，SGA对垃圾焚烧飞灰中重金属的固化处理更具有优势。     

SGA对垃圾焚烧飞灰中重金属的固化性能研究

根据EPA1311、HJ／T299—2007、HJ／T300—2007和HJ557—2009等国内外不同标准，研究了深圳某垃圾焚烧发电厂垃圾焚烧飞灰的浸出毒性，探讨了六硫代胍基甲酸（sixthioguanidineacid，SGA）、二甲基二硫代氨基甲酸盐（sodiumdimethyldithiocarbamate，SDD）和Ca（OH）2浓度对垃圾焚烧飞灰中重金属的固定性能的影响。研究结果表明，随着浸提液pH的降低，该厂焚烧飞灰中大部分金属元素的浸出量增大，焚烧飞灰浸出液中的cd、Ni、Ph和zn浓度分别超过国家危险废物鉴别标准（GB5085．3—2007）规定值的4．75倍、1．47倍、6．72倍和2．20倍，属于危险废弃物，必须进行稳定化处理。当固化剂SGA加入量为0．1mol／kg时，稳定化后的重金属浸出浓度已经低于危险废物鉴别标准，且对Cd、Cr、Cu和Pb的固化性能优于SDD和Ca（OH）2；当固化剂SGA、SDD和Ca（OH）2加入量为0．5mol／kg时，稳定化后的焚烧飞灰重金属浸出浓度均低于国家危险废物鉴别标准（GB5085．3-2007）中的规定值。与SDD和Ca（OH）：相比，SGA对垃圾焚烧飞灰中重金属的固化处理更具有优势。     

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.e., species and concentration of VCs, olfactory odor concentration, and theoretic odor concentration, was quantified. Oxygenated compounds and hydrocarbons were the most abundant VCs in the three facilities. Different chemical species were quantified, and the following average concentrations were obtained: transfer station, 54 VCs, 2472.47 μg/m³; incineration plant, 75 VCs, 33,129.25 μg/m³; and landfill site, 71 VCs, 1694.33 μg/m³. Furthermore, the average olfactory odor concentrations were 20,388.80; 50,677.50; and 4951.17, respectively. The highest odor nuisance was detected in the waste tipping port of the incineration plant. A positive correlation between the olfactory and chemical odor concentrations was found with R ² = 0.918 (n = 15, P < 0.01). The result shows odor pollution risk transfer from landfill to incineration plant when adopting thermal technology to deal with the non-source-separated waste. Strong attention thus needs to be paid on the enclosed systems in incineration plant to avoid any accidental odor emission.

     

Hazardous substances in indoor dust emitted from waste TV recycling facility

Various hazardous substances contained in waste TV sets might be released into environment via dust during recycling activities. Two brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), and tetrabromobisphenol A (TBBPA), and five kinds of heavy metals (Cu, Pb, Cd, Cr, and Ni) were detected in indoor dust collected from two workshops (TV dismantling workshop and subsequent recycling workshop). PBDEs concentrations in dust from waste wires recycling line (722,000 ng/g) were the highest among the studied sites, followed by those in manual dismantling–sorting line (117,000 ng/g), whereas TBBPA concentrations were the highest in manual dismantling–sorting line (557 ng/g) and printed circuit board (PCB) recycling line (428 ng/g). For heavy metals, Cu and Pb were the most enriched metals in all dust samples. The highest concentration of Pb (22,900 mg/kg) was found in TV dismantling workshop-floor dust. Meanwhile, Cu was the predominant metal in dust from the PCB recycling line, especially in dust collected from electrostatic separation area (42,700 mg/kg). Occupational exposure assessment results showed that workers were the most exposed to BDE-209 among the four PBDE congeners (BDE-47, BDE-99, BDE-153, and BDE-209) in both workshops. The hazard quotient (HQ) indicated that noncancerous effects were unlikely for both BFRs and heavy metals (HQ?<?1), and carcinogenic risks for Cd, Cr, and Ni (risk?<?10^?6) on workers in two workshops were relatively low.     

Screening of heavy metal containing waste types for use as raw material in Arctic clay-based bricks

In the vulnerable Arctic environment, the impact of especially hazardous wastes can have severe consequences and the reduction and safe handling of these waste types are therefore an important issue. In this study, two groups of heavy metal containing particulate waste materials, municipal solid waste incineration (MSWI) fly and bottom ashes and mine tailings (i.e., residues from the mineral resource industry) from Greenland were screened in order to determine their suitability as secondary resources in clay-based brick production. Small clay discs, containing 20 or 40% of the different particulate waste materials, were fired and material properties and heavy metal leaching tests were conducted before and after firing. Remediation techniques (washing in distilled water and electrodialytical treatment) applied to the fly ash reduced leaching before firing. The mine tailings and bottom ash brick discs obtained satisfactory densities (1669–2007 kg/m³) and open porosities (27.9–39.9%). In contrast, the fly ash brick discs had low densities (1313–1578 kg/m³) and high open porosities (42.1–51. %). However, leaching tests on crushed brick discs revealed that heavy metals generally became more available after firing for all the investigated materials and that further optimisation is therefore necessary prior to incorporation in bricks.     

Medical Waste Disposal

Medical (biomedical) wastes pose numerous potential health and safety hazards. In addition to their infectious and toxic characteristics, the highly variable and inconsistent nature of medical waste streams has increased public concern about storage, treatment, transportation, and ultimate disposal.

In recent years, techniques have been developed to reduce human exposure to the toxic and infectious components of medical wastes. The most commonly used techniques include internal segregation, containment, and incineration. Other common techniques include grinding, shredding, and disinfection, e.g., autoclaving and chemical treatment followed by landfilling.

Of all the available technologies for medical waste treatment and disposal, incineration has been found to be the most effective method overall for destroying infectious and toxic material, volume reduction, and weight reduction in the medical waste stream, incineration destroys the broadest variety of medical waste constituents and can recover energy from the medical waste stream. Incineration also is an appropriate alternative to burial of human pathological remains.     

Single-well, gas-sparging tests for evaluating the in situ aerobic cometabolism of cis-1,2-dichloroethene and trichloroethene

This study developed single-well, gas-sparging tests for assessing the feasibility of in situ aerobic cometabolism of trichloroethene (TCE) and cis-1,2-dichloroethene (cis-DCE) using propane and methane as growth substrates. Tests were performed in groundwater contaminated with TCE (100-400 microg l(-1)) and cis-DCE (20-60 microg l(-1)). A series of gas-sparging tests was performed by first sparging ("bubbling") gas mixtures in a well fitted with a "straddle" packer and then periodically sampling groundwater from the same well to develop concentration profiles and to estimate transformation rate coefficients. Evidence that gas-sparging of propane (or methane) and oxygen had stimulated organisms expressing a propane (or methane) monooxygenase enzyme system and the capability to transform TCE and cis-DCE included: (1) the transformation of sparged ethylene and propylene to their corresponding cometabolic by-products, ethylene oxide and propylene oxide, (2) the transformation of both cis-DCE and TCE in the propane-sparged well, (3) the transformation of cis-DCE in the methane-sparged well, and (4) the inhibition of ethylene and propylene transformations in the presence of acetylene, a known monooxygenase inactivator. At a well sparged with propane, first-order rate coefficients for propane utilization and ethylene and propylene transformation were similar, ranging from 0.007 to 0.010 h(-1). At the well sparged with methane, the propylene first-order transformation rate coefficient was 0.028 h(-1), a factor of 1.8 and 1.6 greater than methane and ethylene, respectively. The results demonstrated that gas-sparging tests are a rapid, low-cost means of assessing the potential for the in situ aerobic cometabolism of cis-DCE and TCE.     

A study of extractive and remote-sensing sampling and measurement of emissions from military aircraft engines

Aircraft emissions contribute to the increased atmospheric burden of particulate matter (PM) that plays an important role in air quality, human health, visibility, contrail formation and climate change. Sampling and measurement of modern aircraft emissions at the engine exhaust plane (EEP) for engine and fuel certification remains challenging, as no agency-certified method is available. In this paper we summarize the results of three recent field studies devoted to investigate the consistency and applicability of “extractive” and “optical remote-sensing” (ORS) technologies in the sampling and measurement of gaseous and PM emitted by a number of military aircraft engines. Three classes of military engines were investigated; these include T56, TF33, and T700 & T701C types of engines, which consume 70–80% of the military aviation fuel each year. JP-8 and Fischer–Tropsch (FT)-derived paraffinic fuels were used to study the effect of fuels. It was found that non-volatile particles in the engine emissions were in the 20 nm range for the low power condition of new helicopter engines to 80 nm for the high power condition of legacy engines. Elemental analysis indicated little metals were present on particles, while most of the materials on the exhaust particles were carbon and sulfate based. Alkanes, carbon monoxide, carbon dioxide, nitrogen oxides, sulfur dioxide, formaldehyde, ethylene, acetylene and propylene were detected. The last five species were most noticeable only under low engine power. The emission indices calculated based on the ORS data deviate significantly from those based on the extractive data. Nevertheless, the ORS techniques were useful in the sense that it provided non-intrusive real-time detection of species in the exhaust plume, which warrants further development. The results obtained in this program help validate sampling methodology and measurement techniques used for non-volatile PM aircraft emissions as described in the SAE AIR6037 (2009).     

Assessment of tropospheric ozone at an industrial site of Chennai megacity

This paper presents the temporal variation in surface-level ozone (O₃) measured at Gummidipoondi near Chennai, Tamilnadu. The site chosen for the present study has high potential for ozone generation sources, such as vehicular traffic and industrial activities. The site is also located near a hazardous waste management facility. The key sources of nitrogen oxides (NO_x), which are considered to be an important precursor of O₃, include hazardous waste incineration, trucks bringing the hazardous wastes, and vehicles plying on the nearby National Highway 16 (NH 16). The measurements clearly showed diurnal variation, with maximum values observed during the noon hours and minimum values observed when solar radiation was less. The data showed a marked seasonal variation in O₃, with the highest hourly average O₃ concentration (497.2 µg/m³) in the summer season. Consequently, in order to identify the long-range transport sources adding to the increased O₃ levels, backward trajectories were computed using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. It was found that the polluted air mass originated from the Southeast Asian region and the Indo-Gangetic Plain. The polluted air mass, which advected large amounts of carbon monoxide (CO) plumes, was analyzed using the Measurement of Pollution in the Troposphere (MOPITT) retrievals. The correlations of O₃ with temperature (r = 0.746; P < 0.01) and solar radiation (r = 0.751; P < 0.01) were strongly positive, and that with NO_x was found to be negative. Stronger correlation of O₃ with NO_x was observed during pre-monsoon months (r = 0.627; P < 0.01) and following hours of photochemical reactions. There were substantial differences in concentrations between weekdays and weekends, with higher nitric oxide (NO) and nitrogen dioxide (NO₂), but lower O₃, concentrations on weekdays. A substantial weekday-weekend difference in O₃, which was higher on weekends, appears to be attributable to lower daytime traffic activity and hence reduced emissions of NO_x to a “NO_x-saturated” atmosphere.

Implications: The assessment of ground-level ozone in an industrial area with hazardous waste management facility is very important, as there is high possibility for more generation of tropospheric ozone. Since the location of the study area is coastal, wind plays a major role in O₃ transportation; hence, the effects of wind speed and wind direction have been studied in different seasons. When compared with the other studies carried out in different places across India, the present study area has recorded much greater O₃ mixing ratio. This study can be useful for setting up control strategies in such industrial areas.     

Regulated and speciated hydrocarbon emissions from a catalyst equipped internal combustion engine

In the present work, the effect of engine operating conditions on its exhaust emissions and on catalytic converter operation is studied. A 4-cylinder OPEL 1.6 l internal combustion engine equipped with a hydraulic brake dynamometer was used in all the experiments. For exhaust emissions treatment a typical three-way catalyst was used. The highest hydrocarbon and carbon monoxide engine-out emissions were observed at engine power 2–4 HP. These emissions were decreased as the engine power was increased up to 20 HP. Among the various compounds detected in exhaust emissions, the following ones were monitored at engine and catalyst outlet: methane, hexane, ethylene, acetaldehyde, acetone, benzene, toluene and acetic acid. The concentration of each compound in the catalytic converter effluent was in the range 45–132, 5–12, 10–125, 15–22, 3–7, 3–12, 2–9, 0–6 ppm, respectively. After the required temperature for catalyst operation had been achieved, carbon monoxide tailpipe emissions were dramatically decreased and the observed hydrocarbon conversions were also high. Methane was the most resistant compound to oxidation while ethylene was the most degradable compound over the catalyst. The order from the easiest to the most resistant to oxidation compound was: Alkene>Aromatic>Aldehyde>Ketone>Alkane.     

Siting Ambient Air Particulate Samplers Near Dirt Roads

There are economic and regulatory incentives for considering alternatives to the direct land disposal of solvent-bearing hazardous waste streams (EPA Hazardous Waste Codes: F001, F002, F003, F004, and F005). These alternatives include recycle/reuse (including use as a fuel substitute), destruction of a stream's solvent component, and treatment prior to land disposal. This paper reviews these three waste management alternatives and discusses their applicability to solvent waste streams having various physical characteristics. Seven waste treatment techniques which may be used to handle solvent wastes are described: incineration, agitated thin-film evaporation, fractional distillation, steam stripping, wet oxidation, carbon adsorption, and activated sludge biological treatment.     

Chemical Manufacturers Association 1984 Hazardous Waste Survey

This paper discusses the Chemical Manufacturers Association's 1984 survey of the chemical industry's hazardous waste management practices. The survey data include a breakdown of how the industry's hazardous wastes are managed, detailing generation, treatment and disposal, and cover 725 plants in 81 companies. The 1984 survey is the third CM A hazardous waste survey, and the paper discusses resultant waste treatment trends from 1981- 1984, the period covered by previous surveys. A total of 278.5 million tons of hazardous waste was treated and disposed by survey respondents. Of this, 276.8 million tons was hazardous wastewater and 1.7 million tons was solid hazardous waste. The survey solid hazardous waste total was projected to the entire industry (Standard Industrial Code 2800) and is estimated at 6.9 million tons. The survey showed continued decreasing trends in hazardous waste generation in the chemical industry. It demonstrated changes in hazardous waste management practices, with decreased use of landfills and increased incineration of the solid wastes that are generated.     

Preliminary Measurements of Biogenic Sulfur-Containing Gas Emissions From Soils

Emission factors for particulate matter and carbon monoxide have been measured for wood, anthracite coal, and bituminous coal burned in residential heaters operated at less than 15 kW (50,000 Btu/hr). In these studies the stove effluent is mixed with about four volumes of outside air and samples are collected about two minutes after mixing. The main purpose of using this sampling method is to simulate atmospheric conditions more closely. Particulate samples are collected on 20 × 25 cm filters after cyclone preseparation of particles larger than 4 μm. Carbon monoxide concentrations are measured with Draeger tubes.

Particulate emission factors for wood ranged from 1.6 to 6.4 g/kg (fuel) and were found to depend on the fuel load and the firing rate, as indicated by earlier studies. These values are substantially less than the values obtained previously for stoves operated under similar conditions. The average particulate emission factors for bituminous and anthracite coal are 10.4 and 0.50 g/kg, respectively. Carbon monoxide emission factors for wood, bituminous, and anthracite coal are 100,116, and 21 g/kg, respectively.     

Emission reductions from woody biomass waste for energy as an alternative to open burning

Woody biomass waste is generated throughout California from forest management, hazardous fuel reduction, and agricultural operations. Open pile burning in the vicinity of generation is frequently the only economic disposal option. A framework is developed to quantify air emissions reductions for projects that alternatively utilize biomass waste as fuel for energy production. A demonstration project was conducted involving the grinding and 97-km one-way transport of 6096 bone-dry metric tons (BDT) of mixed conifer forest slash in the Sierra Nevada foothills for use as fuel in a biomass power cogeneration facility. Compared with the traditional open pile burning method of disposal for the forest harvest slash, utilization of the slash for fuel reduced particulate matter (PM) emissions by 98% (6 kg PM/BDT biomass), nitrogen oxides (NOx) by 54% (1.6 kg NOx/BDT), nonmethane volatile organics (NMOCs) by 99% (4.7 kg NMOCs/BDT), carbon monoxide (CO) by 97% (58 kg CO/BDT), and carbon dioxide equivalents (CO2e) by 17% (0.38 t CO2e/BDT). Emission contributions from biomass processing and transport operations are negligible. CO2e benefits are dependent on the emission characteristics of the displaced marginal electricity supply. Monetization of emissions reductions will assist with fuel sourcing activities and the conduct of biomass energy projects.     

Mixing ratios of volatile organic compounds (VOCs) in the atmosphere of Karachi,Pakistan

Mixing ratios of carbon monoxide (CO), methane (CH₄), non-methane hydrocarbons, halocarbons and alkyl nitrates (a total of 72 species) were determined for 78 whole air samples collected during the winter of 1998–1999 in Karachi, Pakistan. This is the first time that volatile organic compound (VOC) levels in Karachi have been extensively characterized. The overall air quality of the urban environment was determined using air samples collected at six locations throughout Karachi. Methane (6.3 ppmv) and ethane (93 ppbv) levels in Karachi were found to be much higher than in other cities that have been studied. The very high CH₄ levels highlight the importance of natural gas leakage in Karachi. The leakage of liquefied petroleum gas contributes to elevated propane and butane levels in Karachi, although the propane and butane burdens were lower than in other cities (e.g., Mexico City, Santiago). High levels of benzene (0.3–19 ppbv) also appear to be of concern in the Karachi urban area. Vehicular emissions were characterized using air samples collected along the busiest thoroughfare of the city (M.A. Jinnah Road). Emissions from vehicular exhaust were found to be the main source of many of the hydrocarbons reported here. Significant levels of isoprene (1.2 ppbv) were detected at the roadside, and vehicular exhaust is estimated to account for about 20% of the isoprene observed in Karachi. 1,2-Dichloroethane, a lead scavenger added to leaded fuel, was also emitted by cars. The photochemical production of ozone (O₃) was calculated for CO and the various VOCs using the Maximum Incremental Reactivity (MIR) scale. Based on the MIR scale, the leading contributors to O₃ production in Karachi are ethene, CO, propene, m-xylene and toluene.     

Environmental pollution from the use of alternative fuels in a four-stroke engine

This paper discusses the use of the fuels propane and butane–propane (80:20) in a four-stroke engine made to function with gasoline (petrol). The experiment covered gas emissions, emissions temperature and fuel consumption. It was observed that gas emissions were reduced compared with gasoline. The reduction for carbon monoxide emissions was greater when butane–propane was used. The same was true for hydrocarbon emissions when the electrical load was below 1500 W, but above 1500 W propane performed better. Higher emissions temperatures were observed with both alternative fuels. Under unloaded conditions the emissions from propane combustion have higher temperature, whereas under full load conditions the emissions from the combustion of the butane–propane mixture have higher temperature. The consumption of propane is lower than that of the mixture.     

A Comparison of Dioxin,Furan and Combustion Gas Data from Test Programs at Three MSW Incinerators

Dioxin, furan and combustion gas data from test programs conducted at the Pitts field, Prince Edward Island, and Peekskill municipal solid waste incinerators were compared to identify similar and discrepant results. Dioxin and furan concentrations sampled upstream of air pollution control devices are related to a variety of combustion gas variables monitored in the high temperature zones of the incinerators. The effects of temperature, excess oxygen, carbon monoxide, hydrochloric acid gas, flue gas moisture, particulate loading and refuse moisture and PVC content are discussed. Conclusions are made and future research needs are discussed.     

Treatment Technologies For Hazardous Wastes: Part III Treatment Technologies for Corrosive Hazardous Wastes

In this paper, the authors present generation and treatment information for corrosive hazardous wastes (EPA Hazaradous Waste Codes D002 and K062). The authors discuss the state of the art for several treatment trains used to process specific types of corrosive waste. Treatment trains incorporate various unit processes selected from but not limited to the following: neutralization, filtration, carbon adsorption, biological oxidation, distillation, air flotation, and incineration. Unit processes are selected to form trains according to the corrosive characteristics of each individual waste stream. The treatment processes discussed are proposed to be used instead of landfills for disposal of corrosive waste.