title: Memory effect driven emissions of persistent organic pollutants from industrial thermal processes, their implications and management: a review.
abstract: Memory effect is delayed emission of certain persistent organic pollutants (POPs). Many of the POP compounds viz. polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) get trapped in the particulate phase deposited in the flue transfer lines and air pollution control systems (equivalent to storage in the memory of a system) and released subsequently. Memory effect driven emission is a combination of real time emission and emission of stored compounds and so is not a true measure of actual real time emission. Memory effect is now realized to have existed for a long time but was not identified and understood until recently. Memory effect has several serious implications e.g. it wrongly depicts emission patterns of POPs; it makes compliance to stipulated emission standards difficult; it could lead to wrong calculations of emission factors and emission inventory estimates of a plant and leads to misinterpretation of efficacy of processes and air pollution control systems. Further, new PCDD/Fs may be formed in the trapped particulate phase via de novo synthesis and the new compounds may be emitted, thereby increasing total PCDD/F emissions, apart from altering the homologue pattern of PCDD/Fs in emissions. Memory effect could be minimized by judicious operational and management (O&M) procedures like optimizing combustion, minimizing unnecessary halts in operations, periodical cleaning of flue transfer lines, application of inhibitors etc.
authors.affiliation: Air Pollution Control Division, National Environmental Engineering Research Institute, Nehru Marg, Nagpur 440020, India.
authors.forename: Jitendra
authors.initials: J
authors.lastname: Trivedi
authors.forename: Deepanjan
authors.initials: D
authors.lastname: Majumdar
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001572:Benzofurans / Q000032:analysis*; D017745:Incineration; D007220:Industrial Waste; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D001572:Benzofurans; D007220:Industrial Waste; D000072317:Polychlorinated Dibenzodioxins; D011084:Polycyclic Aromatic Hydrocarbons