scholarly journals Measurement of Dioxin Emissions from a Small-Scale Waste Incinerator in the Absence of Air Pollution Controls

2019 ◽  
Vol 16 (7) ◽  
pp. 1267 ◽  
Author(s):  
Gang Zhang ◽  
Xiangxuan Huang ◽  
Wenbo Liao ◽  
Shimin Kang ◽  
Mingzhong Ren ◽  
...  
Keyword(s):  
Air Pollution ◽  
Solid Waste ◽  
De Novo ◽  
Dominant Role ◽  
Small Scale ◽  
Waste Incinerator ◽  
Bag Filter ◽  
Mean Values ◽  
Carbon Injection ◽  
Waste Incinerators

Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) emissions from basic small-scale waste incinerators (SWI) may cause health risks in nearby people and are thus subject to stringent regulations. The aim of this study was to evaluate PCDD/F emission and reduction of a basic SWI in the absence of air pollution controls (APCs). The results indicated that the stack gas and fly ash presented average PCDD/F levels and emission factors of 3.6 ng international toxic equivalent (I-TEQ)/Nm3 and 189.31µg I-TEQ/t and 6.89 ng I-TEQ/g and 137.85µg I-TEQ/t, respectively, much higher than those from large municipal solid waste incinerators (MSWI). PCDD/Fs congener fingerprints indicated that de novo synthesis played a dominant role in the low-temperature post-combustion zone and increased the presence of high-chlorine substituted congeners. On the basis of the emission factor 327.24 µg I-TEQ/t-waste, approximately 3000 g I-TEQ dioxins might be generated in total through basic SWIs and open burning. After refitting an SWI by adding activated carbon injection with a bag filter (ACI+BG), the PCDD/F emissions decreased to mean values of 0.042 ng I-TEQ/Nm3, far below the standard of 0.1 ng I-TEQ/Nm3, and the removal efficiency reached 99.13% in terms of I-TEQ. Therefore, it is entirely feasible to considerably reduce PCDD/F emissions by refitting basic SWI, which is positive for the future development of rural solid waste (RSW (RSW) disposal by SWI.

Polychlorinated Dibenzo-P-Dioxins and Dibenzofurans from a Grate-Type Municipal Solid Waste Incinerator in China

2014 ◽  
Vol 878 ◽  
pp. 616-621
Author(s):  
Jian Jun Zhong ◽  
Gang Zhang ◽  
Jing Hai ◽  
Jia Yang Lv ◽  
Jie Ru Zhang ◽  
...  
Keyword(s):  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Flue Gas ◽  
De Novo ◽  
Dominant Role ◽  
Bottom Ash ◽  
Waste Incinerator ◽  
Municipal Solid Waste Incinerator ◽  
Solid Waste Incinerator

The emission characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were evaluated from a grate-type municipal solid waste incinerator (MSWI). The stack flue gas, fly ash and bottom ash samples were sampled and analyzed. Results indicated that the flue gas, fly ash and bottom ash presented their mean dioxin levels of 0.0723 ng I-TEQ/Nm3, 0.614 ng I-TEQ/g and 13.33 ng I-TEQ/kg respectively. The PCDD/Fs congener patterns, in flue gas, fly ash and bottom ash, showed large similarities in both concentration and I-TEQ profiles. The de novo synthesis plays a dominant role in the low-temperature post-combustion zone.

scholarly journals Simulation and Optimization of Municipal Solid Waste Combustion: A Case Study of a Fixed Bed Incinerator

2020 ◽  
pp. 5-19
Author(s):  
Arthur M. Omari ◽  
John P. John ◽  
Baraka Kichonge
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Fixed Bed ◽  
Small Scale ◽  
Waste Incinerator ◽  
Simulation And Optimization

In this study, a Computational Fluid Dynamics (CFD) technique was used to develop a model for the simulation and flow conditions of the incinerator. The CFD technique are based on subdividing the volume of interest, i.e., the combustion chamber (or other parts of the plant) into a grid of elementary volumes. The relevant equations of conservation (mass, momentum, energy) are then applied to each of those elements, after defining all inputs, outputs and boundary conditions. The resulting system is then integrated from start to finish, after introducing momentum, mass and heat transfer. The objective of the study was to evaluate and optimize the performance of locally available incinerators in Tanzania. The small scale municipal solid waste incinerator modelling was done by using a fluent solver. The case study of the existing incinerator at a Bagamoyo hospital in Tanzania was used as a model and the obtained values were compared with simulated results and other publications for validation. The design optimization using CFD techniques to predict the performance of incinerator showed the deviation of input air by 14%, the mass flow rate by 26.5%, the mass fraction of carbon dioxide by 10.4% and slight deviation of nitrogen dioxide and carbon monoxide. The study suggested removing the ash during the incineration process by using a moving grate mechanism to minimize the possibility of formation of NOX. The study found the maximum mass flow rate capacity of incinerator to be 68kg/h with input air A1 as 0.03639 kg/s, input air A2 as 0.03046 kg/s and input air A3 as 0.03409 kg/s. The findings indicated that as capacity is scaled up, the available momentum declines relative to the dimensions of the furnace.

A full-scale study on thermal degradation of polychlorinated dibenzo-p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash and its secondary air pollution control in China

2016 ◽  
Vol 35 (4) ◽  
pp. 437-443 ◽  
Author(s):  
Xingbao Gao ◽  
Bingjing Ji ◽  
Dahai Yan ◽  
Qifei Huang ◽  
Xuemei Zhu
Keyword(s):  
Air Pollution ◽  
Fly Ash ◽  
Thermal Degradation ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Waste Incinerator ◽  
Municipal Solid Waste Incinerator ◽  
Air Pollution Control ◽  
Secondary Air ◽  
Solid Waste Incinerator

Degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash is beneficial to its risk control. Fly ash was treated in a full-scale thermal degradation system (capacity 1 t d−1) to remove polychlorinated dibenzo- p-dioxins and dibenzofurans. Apart from the confirmation of the polychlorinated dibenzo- p-dioxin and dibenzofuran decomposition efficiency, we focused on two major issues that are the major obstacles for commercialising this decomposition technology in China, desorption and regeneration of dioxins and control of secondary air pollution. The toxic equivalent quantity values of polychlorinated dibenzo- p-dioxins and dibenzofurans decreased to <6 ng kg−1 and the detoxification rate was ⩾97% after treatment for 1 h at 400 °C under oxygen-deficient conditions. About 8.49% of the polychlorinated dibenzo- p-dioxins and dibenzofurans in toxic equivalent quantity (TEQ) of the original fly ash were desorbed or regenerated. The extreme high polychlorinated dibenzo- p-dioxin and dibenzofuran levels and dibenzo- p-dioxin and dibenzofuran congener profiles in the dust of the flue gas showed that desorption was the main reason, rather than de novo synthesis of polychlorinated dibenzo- p-dioxins and dibenzofurans in the exhaust pipe. Degradation furnace flue gas was introduced to the municipal solid waste incinerator economiser, and then co-processed in the air pollution control system. The degradation furnace released relatively large amounts of cadmium, lead and polychlorinated dibenzo- p-dioxins and dibenzofurans compared with the municipal solid waste incinerator, but the amounts emitted to the atmosphere did not exceed the Chinese national emission limits. Thermal degradation can therefore be used as a polychlorinated dibenzo- p-dioxin and dibenzofuran abatement method for municipal solid waste incinerator source in China.

scholarly journals Comparative Assessment of Particulate Air Pollution Exposure from Municipal Solid Waste Incinerator Emissions

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Danielle C. Ashworth ◽  
Gary W. Fuller ◽  
Mireille B. Toledano ◽  
Anna Font ◽  
Paul Elliott ◽  
...  
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Exposure Assessment ◽  
Dispersion Model ◽  
Atmospheric Dispersion ◽  
Comparative Assessment ◽  
Waste Incinerator ◽  
Exposure Misclassification ◽  
Ambient Exposure ◽  
Waste Incinerators

Background.Research to date on health effects associated with incineration has found limited evidence of health risks, but many previous studies have been constrained by poor exposure assessment. This paper provides a comparative assessment of atmospheric dispersion modelling and distance from source (a commonly used proxy for exposure) as exposure assessment methods for pollutants released from incinerators.Methods.Distance from source and the atmospheric dispersion model ADMS-Urban were used to characterise ambient exposures to particulates from two municipal solid waste incinerators (MSWIs) in the UK. Additionally an exploration of the sensitivity of the dispersion model simulations to input parameters was performed.Results.The model output indicated extremely low ground level concentrations of PM10, with maximum concentrations of <0.01 μg/m3. Proximity and modelled PM10concentrations for both MSWIs at postcode level were highly correlated when using continuous measures (Spearman correlation coefficients ~ 0.7) but showed poor agreement for categorical measures (deciles or quintiles, Cohen’s kappa coefficients ≤ 0.5).Conclusion.To provide the most appropriate estimate of ambient exposure from MSWIs, it is essential that incinerator characteristics, magnitude of emissions, and surrounding meteorological and topographical conditions are considered. Reducing exposure misclassification is particularly important in environmental epidemiology to aid detection of low-level risks.

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

2018 ◽  
Vol 5 (7) ◽  
pp. 172056 ◽  
Author(s):  
Xuan Cao ◽  
Longjie Ji ◽  
Xiaoqing Lin ◽  
William R. Stevens ◽  
Minghui Tang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Hazardous Waste ◽  
De Novo ◽  
Solid Phase ◽  
Bag Filter ◽  
Start Up ◽  
Equivalent Quantity ◽  
Comprehensive Diagnosis ◽  
Wet Scrubber ◽  
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.

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