Characterization of Dioxin-Furan Emission from Incineration Process

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Chapter 2: Literature Review

Introduction

In many regions, there is interest options for solid waste management municipal (MSW) in a proper way so economically and environmentally. Programs recycling and composting are options applicable to all cases of management MSW. However, these programs reduce only about 20% the volume of waste, the rest is deposited in landfills or processed in incineration plants where solid waste materials and energy can be recovered. In many countries, restrictions on the use of land, geographical features and the concern air quality and water make it impossible to creation of new landfills. The burning helps to solve the problem layout where the space is filled or unavailable or too expensive, yet generated much public concern about environmental pollution problems which may cause (Mckay 2002 343).

A properly designed incinerator should, in theory, transform hydrocarbons only simple carbon dioxide and water. Practical experience shows, no however, that even the best systems of combustion can cause the reaction complete at this point. During and after combustion, waste components dissociate and recombine, forming hundreds or even thousands, of new substances called products of incomplete combustion. The incineration does not affect heavy metals (lead, chromium, cadmium, mercury), which remain intact to the output of the process. For this, incineration not only commits health of the current population but for future generations.

Dioxin/Furan

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are a group of tricyclic aromatic hydrocarbons substituted with one to eight chlorine atoms. These compounds are generally known as 'dioxins' or 'dioxins and furans'. Dioxins are a group of chemicals compounds which are rarely spontaneously in nature, except those resulting from field fires, brush and forest. Their accumulation in the atmosphere began around 1900 when the founder Dow Chemical invented a process for break down on table salt and sodium atoms chlorine and obtain large amounts of free chlorine available for the first time. Initially, Dow Chemical Chlorine considered as a useless and dangerous waste but soon found a way to convert this waste into a useful product, creating a vast array of Chlorinated Hydrocarbons. These new chemicals led to many pesticides, solvents and plastics used in today. Unfortunately, when these chlorinated hydrocarbons are processed in a chemical plant or burnt in an incinerator releases dioxin. All forms of incineration and processes that use any fossil fuel cause dioxin emissions. Except for releases of the past, the chlorine industry chlorinated products are among the lowest dioxin sources today (Pereira 2006 165).

Combustion and Incineration

Dioxin like compounds can be generated or released to the environment from various processes combustion like from chlorine donors' compounds. These include incineration processes: solid waste municipal sludge from waste water treatment, waste medical and hazardous and corpse's crematoria, in addition, the processes metal such as steel production, smelting operations and also the combustion coal, wood, petroleum products and used tires for power generation or heat.

Processes Chemicals

Dioxins are formed as byproducts manufacture of chlorine compounds such as chlorinated phenols, PCBs, fenoxiherbicidas, chlorinated benzenes, aliphatic chlorinated catalysts, chlorinated diphenyl ...