Destruction of PCDD/Fs by SCR from flue gases of municipal waste incinerator and metal smelting plant

Low-temperature catalytic oxidation of PCDD/Fs over MnCeCoOx/PPS catalytic filter

Catalytic destruction of nitrogen oxides (NOx) combined with dust removal technique has attracted much attention, yet the application in the solid waste incineration air pollution control process is still lacking due to the complex flue gas atmosphere. In this work, the Mn-Ce-Co-Ox catalyst-coated polyphenylene sulfide (PPS) filter fiber with efficient dust removal and low-temperature polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) destruction has been prepared with a redox-precipitation method. The catalyst was uniformly grown around the PPS fiber with appropriate catalyst loading. The effects of several key operating parameters (e.g., reaction temperature, catalyst loading amount, and filtration velocity) on the catalytic efficiency were comprehensively investigated. The results show that the Mn-Ce-Co-Ox/PPS has a decomposition yield of 78.0% in PCDD/Fs and 96% in nitric oxide (NO) conversion at 200 °C. The poisoned catalytic filter exhibits a removal efficiency of 88.6% for PCDD/Fs. In addition, the catalytic filter can completely reject particles smaller than 1.0 μm with a low filtration resistance. Therefore, this efficient and energy-conserving catalytic filter shows promising applications in flue gas pollution treatments.

Influence of different loads on PCDD/F removal by SCR during municipal solid waste incineration

This study was conducted on a full-scale (500 t/d) municipal solid waste incinerator (MSWI), investigating the influence of different loads on the emission of polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD/Fs) and their removal by selective catalytic reduction (SCR) system. The total concentration of PCDD/Fs at the SCR inlet under 100% load was higher than that under 80% load. The changing loads caused different distribution characteristics of PCDD/Fs at the SCR inlet, and the dominant congeners changed from high-chlorinated PCDDs (80% load) to low-chlorinated PCDFs (100% load). Moreover, the increased load enhanced the removal efficiency of PCDD/Fs by SCR from 17.3% to 64.2%, which was influenced by the inlet PCDD/F distribution and the moisture content. The high-chlorinated PCDD/Fs with the more stable structure were more difficult to be deteriorated and the high moisture content can weaken the catalytic activity of SCR catalysts. Correlation analysis was used to study the relationship between major air pollutants and PCDD/F emissions. The results showed that HCl positively correlated with PCDD/F emission concentrations, while NOx and SO2 negatively correlated. The results of this study can provide a reference for MSWI to operate properly under variable loads.

Elimination of PCDD/Fs over Commercial Honeycomb-Like Catalyst of V2O5-MoO3/TiO2 at Low Temperature: From Laboratory Experiments to Field Study

With the need for ultra-low emissions and the strict regulation of PCDD/Fs from MSWI plants, traditional SCR catalysts have been applied to remove PCDD/Fs. In this study, we compared one typical commercial V2O5-MoO3/TiO2 catalyst’s performance in removing PCDD/Fs under laboratory and industrial conditions. Various characterization methods like XRF, XPS, BET, and H2-TPR were applied to analyze the catalyst’s properties. The laboratory results showed that the adsorption could significantly affect the removal at low temperatures. The RE on PCDD/Fs was 59.4% (55.0% for toxicity RE), 88.5% (90.3%), and 78.0% (76.0%) at 160 °C, 180 °C, and 200 °C, respectively, showing that 180 °C is the most suitable operation temperature for this V2O5-MoO3/TiO2 catalyst. The field study was conducted at 180 °C, and the results revealed that the competition between water vapor and the interaction of SO2 could lower the RE. However, comparisons between laboratory and field conditions showed that this V2O5-MoO3/TiO2 catalyst still showed good stability, with only a 6.8% drop.

PCDD/F removal at low temperatures over vanadium-based catalyst: insight into the superiority of mechanochemical method

The high toxicity and low volatility of PCDD/Fs prevent detailed study of their catalytic degradation removal characteristics. In this study, 1,2-dichlorobenzene (1,2-DCBz) was initially used as a model to investigate the catalytic characteristics of various vanadium-based catalysts prepared by different methods. Then, the optimized catalyst was used for catalytic degradation of real PCDD/Fs at low temperatures based on a self-made stable source. The VO_x/TiO₂ catalysts synthesized by the mechanochemical method (VTi-MC2) had a higher 1,2-DCBz removal efficiency (>85%) and stability (> 420 min) at low temperatures (< 200 °C) compared to VTi-SG (sol-gol method) and VTi-WI (wetness impregnation method). The physicochemical properties of catalysts were studied using comprehensive characterization. It was found that the VTi-MC2 has better VO_x species distribution and possesses the highest V⁵⁺ species and surface adsorbed oxygen content, which are the key factors that contributed to the higher removal efficiency. Accordingly, the mechanochemical method can be used to control the physicochemical properties of catalysts by adjusting the milling parameters. The optimum ball milling time is 2 h and a suitable precursor is NH₄VO₃ for VO_x/TiO₂. Moreover, the removal efficiency and catalytic degradation efficiency of PCDD/Fs in gas phase catalyzed by VTi-MC2 were 97% and 50% respectively, within a range of temperatures below 200 °C, which are both higher than those reported research. In general, the mechanochemical strategy employed in this study provides a means for seeking more efficient catalysts used for low-temperature degradation of various trace organic pollutants.

Occurrence, profiles, and control of unintentional POPs in the steelmaking industry: A review

The steelmaking industry is an important source of unintentionally produced persistent organic pollutants (UP-POPs). This review summarizes the emission levels, characteristics, and formation mechanisms of UP-POPs, including halogenated dioxins, polychlorinated biphenyls, polychlorinated naphthalenes, and penta- and hexa- chlorobenzenes in the steelmaking industry to improve our understanding of the emissions of UP-POPs from the steelmaking industry. The factors influencing UP-POP formation during the iron ore sintering (IOS) process are also reviewed. The raw materials and temperature during the steelmaking process are important factors influencing UP-POP generation. Raw materials containing plastics, paints, cutting oil, rubber, and iron from electronic waste recycling can contribute to high emissions of UP-POPs during steelmaking processes. Electrostatic precipitator dust contains chlorine, carbon, and metals, which are usually recycled as a component of the raw material, and could also promote dioxin formation and emissions from IOS. Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are easily formed in high concentrations at temperatures in the range of 200 °C-650 °C. This review also provides a comprehensive summary of the UP-POP emission limits in the steel industry worldwide and the best available techniques and environmental practices for UP-POP emission reduction. The information in this review will be useful for the reduction of UP-POPs in the steelmaking process.

PCDD/F levels and phase distributions in a full-scale municipal solid waste incinerator with co-incinerating sewage sludge

Co-incinerating sewage sludge in municipal solid waste incinerators (MSWIs) is an up-to-date disposal way with great prospects to market. To verify the environmental safety of this disposal method, a field study was conducted in a MSWI which has achieved PCDD/Fs ultra-low emission. PCDD/F phase partitioning characteristics, congener profiles, and the influence of selective catalytic reduction (SCR) were also investigated. PCDD/F emission levels ranged from 0.0031 to 0.0053 ng I-TEQ/Nm³, distinctly lower than the national standard. For tests co-incinerating 5% sludge, PCDD/F emission levels were averagely 32% lower than tests mono-combusting municipal solid waste. The phase partitioning study found that PCDD/Fs enriched in condensed water took a non-negligible proportion of the total concentration in flue gas. The removal efficiency of SCR in tests co-incinerating sludge was averaged at 41.9%. However, in tests without adding sewage sludge, PCDD/F concentrations in flus gas after SCR were increased. It was found that the elevations were mainly attributed to the increase of low-chlorinated PCDF congeners in gas-phase. By inference, memory effect existing in SCR might be responsible for the increase of PCDD/F levels. PCDD to PCDF ratios in most of the sampling points were >1, suggesting that de novo synthesis is not the dominant formation pathway in the studied incinerator. This study verified that co-incinerating sewage sludge in the MSWI would not elevate the emission levels of PCDD/Fs. If all of the yielded municipal waste is incinerated with adding 5% sewage sludge, more than half of sewage sludge can be disposed safely in Shenzhen.

Catalytic decomposition of dioxins and other unintentional POPs in flue gas from a municipal waste incinerator (MWI) in China: a pilot testing

Unintentionally produced persistent organic pollutants (UPOPs) include polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), pentachlorobenzene (PeCBz), and hexachlorobenzene (HxCBz). With the booming of municipal waste incinerators (MWIs) in China, the emission of UPOPs has generated great concern. As an alternative technology of dioxin control, catalytic decomposition has not been used in China, mainly due to the absence of national demonstration projects. Also, the simultaneous removal of various UPOPs has not been well investigated.In this study, a pilot-scale selective catalytic oxidative (SCO) system using a self-developed honeycomb catalyst was built and tested in a typical municipal waste incinerator (MWI) of China. The original concentration of PCDD/Fs in flue gas after the treatment of activated carbon injection (ACI) still exceeded the national emission standard (0.1 ng I-TEQ/Nm³), while the concentrations of PeCBz and HxCBz were one order of magnitude higher than that of PCDD/Fs. For the testing temperature varying from 300 to 200 °C, the removal efficiency of PCDD/Fs range from 39 to 95 %, followed by dl-PCBs with the range of 56-89 %. PeCBz and HxCBz were also removed, though their removal efficiencies were lower than those of PCDD/Fs and dl-PCBs. Both temperature and degree of chlorination influence the removal efficiencies.

Comprehensive diagnosis of PCDD/F emission from three hazardous waste incinerators

Comprehensive diagnosis of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) emissions was systematically conducted on three hazardous waste incinerators (HWIs). Results indicated that PCDD/F mainly existed in the solid phase before the bag filter. This was especially true for higher chlorinated dioxin and furan congeners (hexa-, hepta- and octa-). The aged bag filters tended to increase the gas-phase PCDD/F. Emissions also increased due to PCDD/F desorption from circulated scrubbing solution and plastic packing media used in the wet scrubber. The PCDD/F concentrations were elevated during the start-up process, reaching up to 5.4 times higher than those measured during the normal operating period. The ratios of PCDFs/PCDDs revealed that the surface-catalysed de novo synthesis was the dominant pathway of PCDD/F formation. Installation of more efficient fabric filters, intermittent replacement of circulated scrubbing solution will result in reduced PCDD/F emission. Additionally, 2,3,4,7,8-PeCDF correlated well with the international toxic equivalent quantity (I-TEQ) value, which suggests that 2,3,4,7,8-PeCDF could act as an I-TEQ indicator.

Catalytic oxidation of PCDD/F on a V2O5-WO3/TiO2 catalyst: Effect of chlorinated benzenes and chlorinated phenols

Catalytic oxidation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) is a well-proven technique, applied in a rising number of Municipal Solid Waste Incineration plants, yet the simultaneous and possibly competitive co-oxidation of other compounds, such as chlorinated benzenes (CBz) or phenols (CP), is still poorly documented. In this study, a grinded commercial catalyst (vanadium-tungsten supported on titanium dioxide) was submitted to exploratory testing: the PCDD/F present in a gas test flow were catalytically oxidised (200°C, 10,000h^-1), either as such or in the presence of benzene (Bz), monochlorobenzene (MCBz), and 1,2-dichlorobenzene (DCBz) and the effect of these additions on the catalytic destruction of PCDD/F was verified experimentally. Both removal efficiency (RE) and destruction efficiency (DE) declined during the exploratory testing and, importantly, some DCBz even converted into supplemental PCDD/F. Also, the occurrence of carbon deposition negatively influenced catalytic oxidation activity. Regeneration with oxygen or air allowed to remove the deposited carbon and the original catalytic activity was largely restored after calcination. In a second part of this study, the PCDD/F-formation from DCBz, hexachlorobenzene (HCBz), o-monochlorophenol (o-MCP) and pentachlorophenol (PeCP) was demonstrated and tentatively explored. To prepare for further elucidation of the reaction mechanism, a complete isomer-specific analysis was prepared.

Emission of unintentionally produced persistent organic pollutants (UPOPs) from municipal waste incinerators in China

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), pentachlorobenzene (PeCBz) and hexachlorobenzene (HxCBz), which are listed in the Stockholm Convention, are commonly known as unintentionally produced persistent organic pollutants (UPOPs). As municipal waste incinerators (MWIs) have burgeoned in China, the emission of UPOPs is of great concerns. Compared to the extensive studies of PCDD/Fs emission, not much information of non-dioxin UPOPs (i.e., PCBs, HxCBz, and PeCBz) is available. In the present study, samples from raw gas (RG) after boiler, stack gas (SG) after air pollution control devices (APCDs) and fly ash (FA) samples were collected from typical MWIs in China. The analyses of SG samples indicate that PCDD/Fs are the major contributor to TEQ value, but non-dioxin UPOPs are the dominant compounds in terms of mass concentration. The mean emission factors of dl-PCBs, PeCBz, and HxCBz in SG are 0.372, 144, and 84.7 μg/t, respectively. In contrast with gaseous samples, FA contains higher mass concentration of PCDD/Fs and PCBs than that of PeCBz and HxCBz. In terms of homologues distribution of PCBs, di- to tetra-CBs were the predominant species in both SG and FA samples. PCB-126 is the major contributor to the TEQ concentration. The comparison of UPOPs composition in SG and RG samples shows that activated carbon adsorption process is capable of removing most PCDD/Fs, but less efficient for the removal of non-dioxin UPOPs.

Study on the impact of industrial flue gases on the PCDD/Fs congener profile in ambient air

The aim of this study was to examine the impact of emissions from combustion processes from sinter, medical, waste and sewage waste incineration plants on the PCDD and PCDF congener profile in ambient air in Krakow (city in Poland). The subject matter of the study were air samples from the outskirts and the city center. It was found that in flue gases from industrial sources and in ambient air the share of PCDF congeners in relation to the total content of PCDD/Fs was higher than the share of PCDDs. However, in air samples collected in the city center, this relationship was reversed. The PCDD congener profiles in flue gases and in air samples are comparable. However, in the samples from the city centre, the share of OCDD is significantly higher and amounts to about 80%. The PCDF congener shares show higher spatial diversity, although in all the analyzed air samples, ODCF and 1,2,3,4,6,7,8 HpCDF dominated. Analyzing the share of congeners in regard to the sum of PCDDs/Fs a mutual resemblance of air from the suburbs, exhaust gases from the sinter ore and sewage sludge incinerator plant was observed. The study showed a similarity between the profile of congeners in air from the city centre and exhaust gases from the medical waste incinerator.

Long-term monitoring and modeling of polychlorinated dibenzo-p-dioxins and dibenzofurans from municipal solid waste incinerators and surrounding area in northern Taiwan

Municipal solid waste incinerators (MSWIs) have long been the major contributors of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) to ambient air in Taiwan. After stringent MSWI emission standards were introduced in 2001, the long-term continuous monitoring of flue gas and ambient air quality became necessary to ensure the effectiveness of the related control strategies. Three MSWIs and the surrounding ambient air were investigated in the current study for PCDD/F characteristics during 2006 to 2011. The average concentrations in the flue gas ranged from 0.008 ~ 0.0488 ng I-TEQ/Nm(3), which is much less than the emission standard in Taiwan (0.1 ng I-TEQ/Nm(3)) (I-TEQ is the abbreviation of International Toxic Equivalent). This led to extremely low levels in the ambient air, 0.0255 pg I-TEQ/Nm(3), much less than the levels seen in most urban areas around the world. Additionally, the results obtained using the Industrial Source Complex Short-Term Dispersion Model (ISCST3) indicate that the PCDD/F contributions from the three MSWIs to the ambient air were only in the range from 0.164 ~ 0.723 %. Principal component analysis (PCA) showed that the PCDD/Fs in the air samples had very similar characteristics to those from mobile sources. The results thus show that stringent regulations have been an effective control strategy, especially for urban areas, such as Taipei City.

Pilot tests on the catalytic filtration of dioxins

Tests were conducted to study the removal efficiencies (REs) of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from flue gas during a test program involving a pilot-scale catalytic filter (CF) module and a full-scale municipal solid waste incinerator (MSWI). The REs attained with the CF on a side stream and a conventional activated carbon (AC) injection and baghouse filtration system in the full-scale MSWI are evaluated via simultaneous sampling and analysis of both gas- and particle-phase PCDD/Fs. Flue gas without AC is supplied to the pilot-scale CF module for evaluating its RE capabilities. The REs achieved with the CF at 180 °C are 96.80 and 99.50%, respectively, for the gas phase and the particulate contained. The gas-phase PCDD/F RE rises significantly at 200 and 220 °C. The air/cloth (A/C) ratio defined as is the gas flow rate (m(3)/min) divided by the filtration area (m(2)) also affects the PCDD/F RE, especially in the gas phase. At 180 °C, a RE of gas-phase PCDD/Fs of 95.94% is attained with the CF at 0.8 m/min, yet it decreases at higher A/C ratios (1 and 1.2 m/min). A significantly lower toxic equivalency (TEQ) concentration (0.71 ng I-TEQ/g) was measured in the filter dust of the CF module compared to that collected by the AC adsorption system (4.18 ng I-TEQ/g), apparently because of the destruction of gas-phase PCDD/Fs by the catalyst.

Quantum chemistry study on the destruction mechanism of 2,3,7,8-TCDD by OH and O(3) radicals

Due to its fundamental importance, the destruction mechanism of the dioxins, as exemplified by 2,3,7,8-TCDD, by OH and O3 radicals was investigated in detail employing Quantum Chemical Calculations in this paper. Theoretical results showed that, OH radical degraded 2,3,7,8-TCDD via substituting chlorine at the 2,3,7,8 positions, while O3 radical degraded 2,3,7,8-TCDD via destructing CC bonds and aromatic ring. Based on the mechanism study, the kinetic parameters of the reactions were also calculated by Transition State Theory. By comparing, the rate constant of the 2,3,7,8-TCDD destruction by OH was found to be much higher than that by O3, which indicated that OH radical have much stronger ability to degrade 2,3,7,8-TCDD than O3 radical. This finding was consistent with the standard electrode potential of OH and O3 radical. The theoretical results in this paper can be believed to supply important theory basis for the further investigation on dioxins removal by using the catalytic oxidation technology.

Emission characterization of unintentionally produced persistent organic pollutants from iron ore sintering process in China

Emission of unintentionally produced persistent organic pollutants (Unintentional POPs), including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychorinated biphenyls (PCBs), hexachlorobenzene (HxCBz) and pentachlorobenzene (PeCBz), were investigated in four typical iron ore sintering plants in China. The emission factors and annual mass releases of the Unintentional POPs were calculated. The results indicated that PCDFs contributed more than 60% to the overall toxic equivalent quantity (TEQ) values, while the contribution of the dl-PCBs is relatively low, and only in the range of 8-9%. The dominant congeners of PCDD/Fs and dl-PCBs contributing most to the total TEQ were 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF and PCB-126. With regard to the TEQ contributions, the most abundant homologues were PeCDFs and HxCDD/Fs, followed by PeCDDs and non-ortho dl-PCB, whereas HpCDD/Fs, OCDD/Fs and mono-ortho dl-PCBs almost made no contributions. Due to the massive use of recycled waste in the feeding materials, the average emission factor of PCDD/Fs and dl-PCBs of the four plants was 3.95 μg WHO-TEQ ton(-1). Based on the results, the annual release of PCDD/Fs and dl-PCBs in 2007-2009 were estimated to be 2070 g, 2212 g, and 2307 gWHO-TEQ, respectively.

A direct method for the decontamination of a fly ash amended wet soil, artificially polluted with dioxins

We report hereby the first method of direct treatment of a wet soil containing toxic polychloroderivatives. Using a system with metallic Ca and 5% Rh fixed on charcoal in methanol, soil samples artificially polluted with fly ash containing polychloro-dibenzodioxins (PCDDs), polychloro-dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (co-PCBs), and having 69.2% to 84.6% moisture content, were successfully treated and decontaminated. This treatment afforded excellent hydrodechlorination yields for the 29 most toxic congeners of PCDDs, PCDFs and PCBs (98.3% degradation yield based on toxic equivalent quotient — or TEQ) after a 24 h treatment, at room temperature.

PCDD/Fs removal efficiency by electrostatic precipitator and wetfine scrubber in an iron ore sintering plant

This study investigates the removal efficiency of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) by the APCDs of an iron ore sintering plant, an electrostatic precipitator (ESP) and a wetfine scrubbing system (WS). The removal efficiencies of the ESP on the total PCDD/Fs concentration and the total PCDD/Fs I-TEQ concentration are 44.3% and 41.4%, respectively, while those of the WS are 66.7% and 68.4%, respectively, but the vapor/solid phase distribution changes after APCDs abatement. At ESP inlet, the PCDD/Fs account for 31.2% in vapor phase and for 68.8% in particulate phase while, at ESP outlet, the PCDD/Fs account for 63.3% in vapor phase and for 36.7% in solid phase. The ESP removes effectively solid-phase PCDD/Fs for its effectiveness to capture the particulate while it is ineffective in removing vapor-phase PCDD/Fs. It, on the contrary, increase for the vaporization within the ESP, especially for these congeners with a lower chlorination degree, and for the PCDD/Fs "stripping" from particulate to gas-phase during the sampling. At WS inlet, the PCDD/Fs account for 63.3% in vapor phase and for 36.7% in solid phase while, at WS outlet, the PCDD/Fs account for 21.4% in vapor phase and for 78.6% in solid phase. Considering that WS outlet temperature is about 40 degrees C, the PCDD/Fs vapor-phase condense to particles: therefore, even if the particulate is removed by WS, the final result is that PCDD/Fs percentage decreases in vapor-phase and increases in solid-phase.

The prospect and development of incinerators for municipal solid waste treatment and characteristics of their pollutants in Taiwan

Taiwan is a small, densely populated island with unique experiences in the construction and operation of incinerators. In such a small area, Taiwan has built 22 incinerators over a short span of time, combusting large amount of municipal solid waste as much as 23,250 tons per day. This study focuses on the history of construction and development of incinerators in Taiwan as well as the characteristics of pollutants, such as heavy metals (Pb, Cd, and Hg), acid gases (NO _x , SO _x , CO, and HCl), and dioxins emitted from the incinerators. Furthermore, the study also covers the generation and composition of municipal solid waste (MSW), and the production of energy in Taiwan. According to Taiwan's data on pollutant emissions, the emission level of pollutants is under control and meets the stringent regulations of Taiwan Environmental Protection Administration (TEPA). Researches have shown that using air pollution control devices (APCDs) in the operation of incinerators provides effective measures for air pollutant control in Taiwan. The main advantage of using incinerators is the generation of electricity (waste-to-energy) during the incineration of municipal solid waste, producing energy that can be consumed by the general public and the industry. Taiwan's extensive experience in incinerator construction and operation may serve as an example for developing countries in devising waste treatment technology, energy recovery, and the control of contagious viral diseases.

Baseline levels of dioxin and furan emissions from waste thermal treatment in Colombia

Background data of polychlorinated dibenzodioxin and dibenzofuran (PCDD/Fs) emissions from the incineration sector in Colombia are presented. Monitoring was carried out during a two-year period, 2003-2005. Twelve plants were sampled for stack gas emissions of dioxins and total solid particulate (TSP). Additionally, PCDD/Fs in several fly ash samples were analyzed. Most incinerators burned industrial refuse materials and medical residues. A wide range of PCDD/Fs emission levels were found. In particular, levels ranging from 6.9 to 343.8 ng I-TEQ/N m(3) were determined in plants without any air pollution control system (APCS). In contrast, 0.5-39.2 ng I-TEQ/N m(3) levels were found in plants with APCS while 8.5-67.5 ng I-TEQ/g were measured in fly ash samples. TSP values ranged from 14 to 448 mg/N m(3). This study also evaluated the impact of implementing different control systems in an incinerator. Finally, for comparison purposes several samples were analyzed by both high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC-HRMS) and high resolution gas chromatography coupled to ion-trap low resolution mass spectrometry-mass spectrometry (HRGC-IT LRMS/MS). Overall, I-TEQ values deviated about 20-30% between both techniques.

Destruction of PCDD/Fs by gliding arc discharges

PCDD/Fs have been become a serious issue because of their toxicological effects and associated adverse health implications. In this study, the gliding arc plasma was tested for treatment of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), which was synthesized from pentachlorophenol in atmospheric condition at 350 degrees C with or without the catalysis of CuCl2. From the experiment, we found that the destruction efficiency of PCDD/F homologues after gliding was discharge ranged from 25% to 79%. This result demonstrates that gliding arc plasma is an effective technology to decompose PCDDs/Fs in flue gas. A plausible degradation mechanism for PCDD/Fs by gliding arc was discussed. Finally, a multistage reactor structure of gliding arc was proposed to upgrade removal efficiency for PCDD/Fs.