Incineration, chlorinated aromatics

The pyrolysis of vinylidene chloride produced a range of chlorinated aromatic compounds including polychlorinated benzenes, styrenes, and naphthalenes (Yasahura and Morita 1988), and a series of chlorinated acids including chlorobenzoic acids has been identified in emissions from a municipal incinerator (Mowrer and Nordin 1987). 

Chlorinated aromatic compounds are hazardous compounds that result from various industrial and agricultural activities. Water disinfection, waste incineration, and uncontrolled use of biocides are the major sources of chlorinated aromatics in the environment. Chlorinated compounds are also formed as subproducts of the biochemical reactions of herbicides containing chlorophe-noxy compounds. Treatment of chlorinated compounds has been studied using biological treatment, adsorption, air stripping, and incineration. Biodegradation of chlorinated compounds is a slow process that is ineffective for extremely low concentrations. Air stripping and adsorption simply trans-... 

Oberg, T., Ohrstrdm, T. and BergstrOm, J. (2007) Metal catalyzed formation of chlorinated aromatic compounds A study of the correlation pattern in incinerator fly ash. Chemosphere 67, S185-S190. 

Fangmark I (1993), Formation of chlorinated aromatic compounds during incineration - an application of statistical experimental design", Dissertation, Universitat Ume3, Schweden Griffin RD (1987), Chemosphere 15 1987-1990. A new theory of dioxin formation in municipal solid waste combustion"... 

Stoll M Furrer J., Seifert H. (2000) Catalytic Destruction of Chlorinated Aromatic Compounds with a V-Oxidc Catalyst Proceed, of ITS Conference on Incineration held in Portland, OR, USA. 

Incineration does not destroy lead and other inorganic chemicals, and they will be emitted or concentrated in the ash. In addition, some organic chemicals form products of inconplete combustion (PICs), which may be more toxic than the chemical contaminant. Incineration of PCBs and some other chlorinated aromatics, for example, can form extremely toxic polychlorinated dibenzo[/>]dioxins and furans. Commercial disposal may be preferred for such waste. 

Zimmermann, R., Blumenstock, M., Heger, H., et al. (2001). Emission of Nonchlorinated and Chlorinated Aromatics in the Flue Gas of Incineration Plants during and after Transient Disturbances of Combustion Conditions Delayed Emission Effects, Environ. Sci. Tech.,35, pp. 1019-1030. 

The fate of aromatic bromine compounds such as brominated dibenzodioxins occurring on fly ash of municipal waste incinerators has been deduced from appropriate laboratory experiments. Stereoselective, first order ipso-substitution of bromine by chlorine is observed. 

Aromatic bromine compounds can be formed and transformed during various thermal processes, like aromatic chlorine compounds (ref. 22). Brominated dibenzodioxins and -furans and mixed brominated/chlorinated compounds have been detected in trace levels in the fly ash of a municipal waste incinerator (ref. 23).Chlorine is generally abundant compared to the bromine of typical municipal waste the chlorine vs. bromine ratio is in the range of 250 1. 

These results show the fate of aromatic bromine compounds during municipal waste incineration bromine is exchanged by chlorine on the surface of fly ash at the electrostatic precipitator at 250-3(X)°C. But the toxic potential at brominated dibenzodioxins and furans is not reduced by these transformations. The increase of PCDD/F concentration in MWI by adding bromine compounds has been pointed out by Lahl and coworkers (ref. 26). 

The use of aromatic brominated compounds as flame retardants has been a potential source of environmental contamination. Incomplete incineration of these compounds and wastes (plastics, textiles, oils etc...) containing brominated flame retardants caused formation of brominated/chlorinated dibenzodioxines (PBDDs/ PCDDs) and dibenzofurans (PCDFs/PBDFs) (refs. 1 - 4). 

Horii Y, Ok G, Ohura T, Kannan K (2008) Occurrence and profiles of chlorinated and brominated polycyclic aromatic hydrocarbons in waste incinerators. Environ Sci Technol 42(6) 1904—1909. doi 10.1021/es703001f... 

PCDD/F and other chlorinated hydrocarbons observed as micropollutants in incineration plants are products of incomplete combustion like other products such as carbon monoxide, polycyclic aromatic hydrocarbons (PAH), and soot. The thermodynamically stable oxidation products of any organic material formed by more than 99% are carbon dioxide, water, and HCl. Traces of PCDD/F are formed in the combustion of any organic material in the presence of small amounts of inorganic and organic chlorine present in the fuel municipal waste contains about 0.8% of chlorine. PCDD/F formation has been called the inherent property of fire. Many investigations have shown that PCDD/Fs are not formed in the hot zones of flames of incinerators at about 1000°C, but in the postcombustion zone in a temperature range between 300 and 400°C. Fly ash particles play an important role in that they act as catalysts for the heterogeneous formation of PCDD/Fs on the surface of this matrix. Two different theories have been deduced from laboratory experiments for the formation pathways of PCCD/F ... 

The vendor claims that the Ariel SST can process soils at rates up to 400% higher than an incineration process. They also state that the technology has been applied to all ranges of petroleum contaminants, including crude oil, as well as nonchlorinated hydrocarbons, chlorinated hydrocarbons, chlorinated pesticides, and polynuclear aromatic compounds. 

Mere destruction of the original hazardous material does not adequately measure the performance of an incinerator. Products of incomplete combustion can be as toxic as, or even more toxic than, the materials from which they evolve. Indeed, highly mutagenic polycyclic aromatic hydrocarbons are generated in the fuel rich regions of most hydrocarbon flames [48]. Dioxin formation in the combustion of chlorinated hydrocarbons has also been reported [49],... 

Peterman RJ, Smith LM, Stalling DL, Petty JD(1986) Identification of chlorinated bi-phenylenes and other polycyclic aromatic compounds formed from the incineration of PCB-dielectric fluids at a capacitor plant s disposal site. Proc of 34th Annual Conference on Mass Spectrometry and Allied Topics, Cincinnati, OH, June 8-13, p 486... 

Historical fluxes of dioxins and dibenzofurans to sediment cores from Lake Erie and Siskiwit Lake (Isle Royale Czuczwa Hites, 1986) suggest that the incineration of chloro-aromatics has been an important source of dioxins and dibenzofurans. In storm sewer and creek sediment samples from the Love Canal chemical dumpsite area in Niagara Falls, N.Y. concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin from 0.9 to 312 ng/g were found (Smith et al., 1983) this compound in the Love Canal area may be associated with a heavy, chlorinated, oily residue. 

Chemical decontamination is an alternative to thermal processing or landfilling of soils contaminated with polychlorinated dibenzo-p- dioxins (PCDD) or other aromatic halides such as chlorobenzenes or polychorinated biphenyls (PCB). Chemical decontamination, like incineration, involves changes to the chemical structure of the dioxin molecule. While chlorinated dioxins are thermally stable, they readily dechlorinate to water soluble compounds under relatively mild conditions of temperature and pressure. 

Rappe, C., Marklund, S., Berggvist, P., and Hansson, M. 1983. In Choudhary, G., Keith, L.H., and Rappe, C. eds.. Chlorinated Dioxins and Dibenzofurans in the Total Environment. Butterworth publishers, Boston Polychlorinated dibenzo-p-dioxins, dibenzofurans and other polynuclear aromatics formed during incineration and polychlorinated biphenyl fires. 

Horii, Y. Ok, G. Ohura, T. Kannan, K. (2008) Occurrence and Profiles of Chlorinated and Brominated Polycyclic Aromatic Hydrocarbons in Waste Incinerators. Environ. Sci. Technol. 42, 1904-1909. 

Ohma, T. Kitazawa, A. Amagai, T. Shinimiya, M. (2007) Relationships between chlorinated polycyclic aromatic hydrocarbons and dioxins in urban air and incinerators. Orgcmohalogen Compd. 69, 2902-2905. 

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