Why chlorinated plastics are not incinerated

Color coding of waste categories with multiple treatment options as defined in Schedule 1 , shall be selected depending on treatment option chosen, which shall be as specified in Schedule 1. Waste collection bags for waste types needing incineration shall not be made of chlorinated plastics.

Different labels for Bio-medical waste containers and bags shall be required for identification and safe handling of this waste. Phone No. Central Govt. Waste Category. Human Anatomical Waste human tissues, organs, body parts. Discarded Medicines and Cytotoxic drugs wastes comprising of outdated, contaminated and discarded medicines.

Solid Waste Items contaminated with blood and body fluids including cotton, dressings, soiled plaster casts, line beddings, other material contaminated with blood. Disposal in municipal landfill. Incineration Ash ash from incineration of any bio-medical waste.

Colour Coding. Type of Containers. Treatment Options as per Schedule 1. Plastic bag. However, such critics would not take into account the improved knowledge acquired over the last decades on thermal combustion systems. To clarify the reasons why the thermal valorisation of PVC can be considered a real alternative to mechanical recycling in solving and optimising its end of life management, it's important to explore the following aspects that relate to the environmental impact of thermal valorisation:.

First one must keep in mind that there are many production processes or activities that emit dioxins, not only the production of chlorine and the PVC lifecycle. Despite this fact PVC has for a long time been accused of being the cause of the dioxin production, although PVC is not the only substance in Municipal Solid Waste MSW which contains chlorine - plants, food and paper are all among the waste streams which contribute to the chlorine present in MSW.

In fact, the production of dioxins depends more on the quality of incineration than on the type of materials burned. Before the mid-eighties it was believed that the presence of dioxins in the gaseous emissions from incinerators could result from their formation during the combustion of chlorinated organic compounds or from the pyrolysis of lignin and cellulosic substances present in waste.

These assumptions, formulated almost thirty years ago, were for some time considered plausible and should not be underestimated. To limit the presence of these micro-pollutants in gaseous emissions, technologies have been developed over the years that have enabled:. Given this knowledge of the mechanisms of dioxin formation, the scientific community now unanimously considers that PVC cannot be given the full responsibility for the presence of dioxins in the flue gas emitted from incinerators.

This is confirmed by a trial done a few years ago at an MSW incinerator in Hamburg, in order to verify the impact of an increase of PVC in the waste on emissions. No influence on the quality of gas emissions was observed. In conclusion, since the second half of the eighties the problem of reducing emissions of dioxins and organic micro-pollutants has been considered solved at the scientific and technology level.

The combination of the following features ensures the reduction of dioxins down to values below the acceptable limits:. In addition to hydrochloric acid which is produced whether PVC is present or not , incinerator emissions also include sulphur and nitrogen compounds.

During the waste combustion process the rupture of the polymer chain, resulting in the release of chlorine in the form of HCl gas. Even in the absence of PVC, due to other sources such as household chlorine in the waste, combustion will always produce gaseous HCl that must be destroyed prior to the release into the atmosphere.

It must be emphasised that the removal of HCl gas is facilitated by its chemical characteristics, whereas it is more difficult to remove SOx, which should be blamed as the largest contributor to acid rain. Chlorine also has a positive contribution in flue gas, as it allows better capture of the heavy metals present in MSW waste, thereby reducing emissions into the environment. The acid gases, above all SOx and HCl, are mostly neutralised by adding alkaline substances, thus producing the corresponding salts.

The amount of neutralisation residues depends on the type of technology used dry, semi dry, wet, semi wet. In the case of municipal solid waste incineration, assuming for example that PVC is responsible for approximately half the production of HCl while the wood, paper and other materials present are responsible for the rest, it was estimated that the traditional neutralisation process based on the use of hydrated lime requires that the residues are disposed of in a landfill for hazardous waste.

Today there are other processes that enable recycling a significant part of the neutralisation residues, among which the NEUTREC process uses sodium bicarbonate injected dry in the acid fumes, after they have passed an electrostatic filter to mostly eliminate them from the fly ash. Sodium bicarbonate neutralises the acids and transforms them into sodium salts that are captured by a filtration section and collected, while the purified flue gas can be emitted to the atmosphere.

Note that the sodium bicarbonate also contributes to absorb a large part of the heavy metals and dioxins, when injected together with activated charcoal. The sodium salts generated by the neutralisation of acid gases, once collected in the final stage of filtration, may be recovered in a dedicated section, where they are dissolved in water with additives to promote the precipitation of metals, and subjected to a filtration.

The insoluble phase is sent to disposal while the soluble phase brine , after being further purified, is recycled for the industrial production of sodium carbonate.