Influence of memory effect caused by aged bag filters on the stack PCDD/F emissions.

To our best knowledge, this study is the first research which investigates whether the PCDD/F memory effect could also be caused by bag filters. In this study, the PCDD/F characteristics of the flue gases in front of and behind the bag filters of one municipal solid waste incinerator (MSWI) and two electric arc furnaces (EAFs) were investigated to clarify the memory effect of PCDD/Fs and their influence on emissions. After the bag filters were operated for over four years, the PCDD/F concentrations in the stack flue gases were all higher than those prior to the aged bag filter, rendering a negative PCDD/F removal.

Uptake of polychlorinated dibenzo-p-dioxins and dibenzofurans in laying ducks.

Uptake of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in laying ducks was determined at different degree of feed contamination. To observe the extent of the transfer of 17 PCDD/Fs from feed to the duck eggs and duck meat, 18 ducks were divided into 3 groups (6 in each group) and fed feed with two different levels of PCDD/Fs. As a control, one group of ducks was fed with the non-contaminated feed for comparison, while the other 2 groups were exposed to the feed doped with EAF dusts (fly ash).

Removal and retention of viral aerosols by a novel alumina nanofiber filter.

Nanomaterial, due to its unique physical, chemical and biological properties compared to its bulk counterparts, has the potential to provide a product superior to its bulk predecessor. In this study, a novel alumina nanofiber filter was assessed for its removal and retention capability for MS2 aerosol. Its physical removal efficiency in the 10-400 nm range was 94.

Assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans contribution from different media to surrounding duck farms.

Since the "Toxic Egg Event" broke out in central Taiwan, the possible sources of the high content of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in eggs have been a serious concern. In this study, the PCDD/F contents in different media (feed, soil and ambient air) were measured. Evaluation of the impact from electric arc furnace dust treatment plant (abbreviated as EAFDT plant), which is site-specific to the "Toxic Egg Event", on the duck total-PCDD/F daily intake was conducted by both Industrial Source Complex Short Term model (ISCST) and dry and wet deposition models.

Removal characteristics of PCDD/Fs by the dual bag filter system of a fly ash treatment plant.

In this study, a dual bag filter system was established to decrease the concentration of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in the stack flue gases of a fly ash treatment plant, which retained zinc from the fly ash of electric arc furnaces. Compared to the original single bag filter system with activated carbon injection (ACI) of 40 kg h(-1), the PCDD/F concentrations in the stack flue gas after the plant was equipped with the dual bag filter system dropped enormously from 3.38-7.

Fate of polychlorinated dibenzo-p-dioxins and dibenzofurans in a fly ash treatment plant.

To understand the fate of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in a fly ash treatment plant that used the Waelz rotary kiln process (hereafter the Waelz process), the samples of input and output media were collected and analyzed. The most important PCDD/F source in input mass was electric arc furnace (EAF) fly ash, which had a mean PCDD/F content of 18.51 ng/g and contributed more than 99% of PCDD/F input mass, whereas the PCDD/F input mass fractions contributed by the coke, sand, and ambient air were only 0.

A novel method to enhance polychlorinated dibenzo-p-dioxins and dibenzofurans removal by adding bio-solution in EAF dust treatment plant.

In order to understand the effect of different amounts of powder-activated carbon (PAC) injection and bio-solution (NOE-7F) addition on the removal efficiencies of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in a fly ash treatment plant with Waelz rotary kiln process, the PCDD/F concentrations in the stack flue gasses were measured and discussed. In the amount of 20, 40 and 50 kg/h PAC injection, the removal efficiencies of PCDD/Fs in the stack flue gas were 86, 96 and 97%, respectively. While adding more amounts of PAC did enhance the removal efficiencies, the reduction fractions of low chlorinated PCDD/F congeners were much higher than those of highly chlorinated PCDD/F congeners.

Characterization and inventory of PCDD/F emissions from coal-fired power plants and other sources in Taiwan.

The objectives of the present study were to quantify (1) the emission factors of a variety of dioxin emission sources; (2) the overall dioxin emission inventory in Taiwan as well as in a major metropolitan (KC area); and (3) the contribution of power plants to the overall PCDD/F emission. To achieve these goals, a total of 95 flue gas samples were collected and analyzed for 17 PCDD/Fs from 20 sources to develop emission factors. The emission factor of PCDD/Fs from coal-fired power plants (0.

Effects of burnings of wax apple stubble and rice straw on polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in air and soil.

Measurements of the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were made in ambient air, ash, and soil impacted by the open burning of wax apple and rice straw residues. Measurements showed that the mean PCDD/F concentration (0.458 pg I-TEQ/Nm3; international toxicity equivalence) in air at two wax apple orchards during open burning increased markedly, -8.

Inhibition of polybrominated dibenzo-p-dioxin and dibenzofuran formation from the pyrolysis of printed circuit boards.

Waste printed circuit boards containing brominated flame retardants were pyrolyzed in a high-temperature melting system to observe the formation behaviors of polybrominated dibenzo-p-dioxins (PBDDs) and dibenzofurans (PBDFs). In this study, the results showed that the formation of PBDD/ Fs during pyrolysis can be destroyed under controlled primary combustion conditions. There were two significant factors that influenced the extent of PBDD/F formation.

Effect of raw materials on emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans from the stack flue gases of secondary aluminum smelters.

The present study was undertaken to investigate the effect of raw materials on PCDD/F emission from secondary aluminum smelters (ALS). Four plants each of aluminum ingot smelters (over 50% ingot) and secondary ALS (over 70% waste or recycled aluminum) were selected and the results compared. The secondary ALS yield much higher PCDD/Fs than the aluminum ingot smelters, or 7.