Ingrid Fängmark

Formation and degradation of chlorinated aromatic compounds in an air pollution control device for MSW combustor

Abstract A municipal solid waste combustor (MWC) in Avesta Sweden, was equipped with an electrostatic precipitator (ESP), a dry scrubber (DS), a fabric filter (FF) and an additional add-on air pollution control system indcuding wet scrubber (WS) and a condensation device (CD). Higher levels of polychlorinated dioxins and dibenzofurans (PCDD/Fs) were found after the additional add-on air pollution control system than after the fabric filter. The results indicate a formation or a transformation of PCDD/Fs in the wet scrubber and in the condensation device.

The Influence of Fly Ash Load and Particle Size On the Formation of Pcdd, Pcdf, PCBz and Pcb in a Pilot Incinerator

A laboratory-scale, fluidized bed reactor fuelled by a synthetic fuel was used to study the influence of fly ash load, particle size, temperature and residence time on the low-temperature formation of chlorinated aromatic compounds. Large fly ash particles were removed from the flue gases by means of a cyclone at the entrance to the cooling section of the reactor. The experimental variables were varied according to an experimental plan of full factorial design. Polychlorinated dibenzo-p-dioxins, dibenzo-furans, polychlorinated benzenes and biphenyls were analysed in the collected flue gas samples. Despite the fact that most of the fly ash load was removed by the cyclone, formation of chlorinated aromatics occurred to the same extent as in earlier experiments, without the cyclone. These results demonstrate the importance of small fly ash particles in the post-combustion formation of chlorinated aromatics.

A comparative study of the acute inhalation toxicity of smoke from TiO2-hexachloroethane and Zn-hexachloroethane pyrotechnic mixtures

Rats were exposed to white smoke generated from mixtures of titanium dioxide-hexachloroethane (TiO2-HC) and zinc-hexachloroethane (Zn-HC), respectively, in an inhalation chamber operated in the static mode. The dose was varied by varying the amount of smoke mixture and/or the exposure time. The acute inhalation toxicity of TiO2-HC smoke was much lower than the Zn-HC smoke. Thus, the animals survived exposure to TiO2-HC smoke, even at relatively high smoke concentrations. This smoke was irritating to the animals and minor, acute inflammatory changes were seen in lung tissue. In contrast, Zn-HC smoke was very toxic and caused lethal injuries to the experimental animals, even at relatively low concentrations. Pulmonary injuries were extensive and death was due to blood congestion with pulmonary oedema. Since the TiO2-HC and Zn-HC mixtures form TiCl4 and ZnCl2, respectively, a separate study was performed in which rats were exposed to TiCl4 gas or ZnCl2 aerosol. No animals died from exposure to TiCl4 at concentrations between 370 and 2900 mg/m3 for 10 min. The LC50 of ZnCl2 was found to be around 2000 mg/m3 during a 10-min exposure period. The difference between the two types of smoke is explained by the difference in toxicity between TiCl4 and ZnCl2.

Mutagenicity testing of condensates of smoke from titanium dioxide/hexachloroethane and zinc/hexachloroethane pyrotechnic mixtures

Condensates of smoke from titanium dioxide/hexachloroethane and zinc/hexachloroethane pyrotechnic mixtures were investigated for their potential to produce genetic damage in the tester strains TA98, TA100, TA1535 and TA1537 of Salmonella typhimurium and in the mouse bone marrow micronucleus assay. Both smoke condensates contained several chlorinated hydrocarbons among which tetrachloroethylene, hexachloroethane, hexachlorobutadiene and hexachlorobenzene were identified by GC/MS. Condensate of smoke from titanium dioxide/hexachloroethane showed a dose-related positive response in the Salmonella assay with strains TA98 and TA100 in the absence of metabolic activation from rat liver S9 fraction. Both smoke condensates were negative in the micronucleus assay but produced a small but significant depression of erythropoietic activity. The results indicate that smoke condensate from titanium dioxide/hexachloroethane mixtures contains unidentified compound(s) that may be considered mutagenic in the Salmonella assay.

Influence of small fly ash particles on the post-combustion formation of PCDDs, PCDFs, PCBzs and CPs in a pilot incinerator

Abstract Experiments in a laboratory scale fluidized bed reactor using a synthetic fuel which simulates municipal solid waste, show that small fly ash particles ( μ m) have a significant influence on the formation of chlorinated aromatic compounds.

Use of a synthetic refuse in a pilot combustion system for optimizing dioxin emission. Part 1

Abstract An experimental combustion reactor has been constructed. The working principle is a fluidized bed with a variety of simulation alternatives. The reactor is designed to simulate the conditions in a full scale MSW incinerator. To feed the reactor with a homogeneous fuel, a synthetic refuse has been formulated for used in studies of formation of chlorinated dioxins (PCDDs) and chlorinated dibenzofurans (PCDFs).

Studies on sampling methods for PCDDs and PCDFs in stack emission

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in stack emission exist both as vapor and sorbed onto the surface of particles. The partition between the two phases is of a dynamic nature and changes rapidly with temperature. When monitoring stack emissions, a sampling method must be used that efficiently collects both phases as well as any condensation aerosol formed in the sampling train. In this study, the two sampling methods used in Sweden, the cooled probe polyurethane foam plug (PUFP) sampling train and the sampling train recommended by the Swedish Environmental Protection Board has been tested for particle collection ability. The results show that an aerosol filter has to be introduced after the condensor in order to collect particle bound PCDDs and PCDFs efficiently.

High-performance liquid chromatographic determination of hexamethylenetetramine in air

A method for the determination of hexamethylenetetramine (HMTA) in air as formaldehyde 2,4-dinitrophenylhydrazone is described. HMTA aerosol and gas are sampled on a glass-fibre filter impregnated with phosphoric acid and 2,4-dinitrophenylhydrazine. HMTA is quantitatively converted into formaldehyde and the resulting hydrazone is desorbed from the filter and determined by high-performance liquid chromatography with ultraviolet detection.

Emissions of polychlorinated compounds in combustion of biofuel

Abstract The aim of this project is to study the formation of polychlorinated organic compounds when miscellaneous packaging material is burned in order to evaluate the emission of specific toxic compounds such as chlorinated dioxins. The packaging materials have also been combusted together with waste pellets with a composition corresponding to municipal solid waste (MSW) in order to determine the contribution of the packaging material to the total emission. Exclusively model waste pellets, used packaging pellets and a pelletized biofuel have been burned with the intention of using these as references in this study. The results clearly show that the paperbased packaging material is comparable with biofuel. The emission is comparable to the emissions from the combustion of biofuel. No increase in the emission of chlorinated organic compounds could be seen even when the paperbases hold extended amounts of aluminum or copper. The results of the biofuel and model waste combustion experiments are in agreement with data from full scale incinerators, consequently the emissions from combustion of the paperbases in the pilot reactor are comparable to emissions in full scale combustors without flue gas cleaning.

Determination of Gaseous and Particulate Polyamines in Air Using Sorbent or Filter Coated with Naphthylisothiocyanate

Abstract Aliphatic polyamines, such as diethylenetriamine (DETA), tri-ethylenetetramine (TETA), and tetraethylenepentamine (TEPA) are widely used in industry. Exposure to these polyamines causes irritation of the respiratory tract and skin sensitization. For the determination of polyamines in air, derivatization with 1-naphthylisothiocyanate to polythioureas was evaluated. Reference polythioureas from DETA, TETA, and TEPA were synthesized and identified by mass spectrometry. The polythioureas were determined by high-performance liquid chromatography with ultraviolet detection. The method was validated by generation of DETA vapor and TETA and TEPA aerosols. 1-Naphthylisothiocyanatecoated Amberlite XAD-2 was used for the sampling of DETA and coated glass fiber filters for TETA and TEPA. The sensitivity of the method was 0.01 mg/m3, and the precision, as relative standard deviation of spiked samples, was 4 percent.