space Press Releases, News Stories

Environmental News Service

GENEVA, Switzerland, 23 January 2002 -- Experts from some 100 governments meeting here have adopted a set of technical guidelines for protecting human health and the environment from the improper management and disposal of plastic wastes.

In many developing countries, plastics are disposed of through landfilling or through open, uncontrolled burning which produces environmental hazards that extend far beyond the burning site.

Baled plastics ready for recycling (Photo courtesy Mountain Recycling, West Virginia) The burning of polyvinylchloride (PVC) plastics produces persistent organic pollutants (POPs) known as furans and dioxins. These pollutants circulate globally and have been associated with adverse effects in humans, including immune and enzyme disorders. They are classified as possible human carcinogens. The new technical guidelines address growing concerns that some developing countries lack the legislation and facilities to cope with increasing piles of plastic wastes of all kinds, each kind requiring a different method of handling and disposal.

To offer a benchmark for best practices, the Technical Guidelines for the Identification and Environmentally Sound Management of Plastic Wastes and for their Disposal were adopted Friday by the Technical Working Group of the Basel Convention on the Control of the Transboundary Movements of Hazardous Wastes and Their Disposal.

They will go forward for final adoption to the 6th meeting of the Conference of the Parties to the Basel Convention, tentatively set for December in Geneva.

"All plastic wastes can be recycled under environmentally sound conditions," the guidelines assert.

"Open burning is not an environmental acceptable solution for any kind of waste," the technical working group emphasized. "Incineration under environmentally sound conditions with energy recovery should be the preferred option compared to landfilling or incineration without energy recovery."

Since incineration without energy recovery does not contribute to saving of resources or reduction of climate change gases, the technical group advises that "this process should be replaced by processes recovering energy as far as possible."

The expert group warns that incomplete incineration of plastic wastes that contain chlorinated compounds and brominated flame retardants will release hazardous doxins and furans into the air. But these wastes can be incinerated safely, the guidelines say.

"Research and practice developed over the past 10 years have shown conclusively that, under strict operating conditions, plastic wastes, even if the mixture is rich of PVC, can be incinerated safely and effectively. Consistent, high temperature combustion will recover the maximum energy from the fuel and ensure the complete breakdown of toxic organic compounds."

Greenpeacers climb a Spanish incinerator stack in protest of hazardous emissions (Photo courtesy Greenpeace) Greenpeace, which submitted comments in the public process that resulted in these technical guidelines, says it is not possible to incinerate wastes in complete safety. "No incinerator process operates at 100 per cent efficiency. Unburned chemicals are emitted in the stack gases of all hazardous waste incinerators. They also escape into the air as fugitive emissions during storage, handling and transport. While incinerators are designed to burn wastes, they also produce them in the form of ash and effluent from wet scrubbers and/or cooling processes," the group says.The role played by chlorinated polymers in the formation of dioxins in waste incinerators has been a matter of controversy, the group acknowledges. "It has been shown that the removal of chlorinated polymers from mixed waste will not bring about a proportionate reduction in dioxin formation, and even if all the PVC is removed from mixed waste, the chlorine remaining is sufficient to form dioxin levels which warrant flue gas treatment."

Still, "The incineration of plastics, with or without energy recovery, under high temperature and the appropriate abatement techniques for flue gases can be performed under environmentally sound conditions," the working group says.

But Greenpeace points out that dioxins are distributed into the environment as part of incinerator stack gases, bottom ash, fly ash and in the effluent of pollution control devices.

The technical working group acknowledges that fly ash from flue-gas cleansing usually contains materials such as heavy metal compounds which could damage the environment if released. "These residues should always be considered to be hazardous and be deposited only in authorized landfills after leaching tests. Sometimes it is found valuable to stabilize the residues with cement before deposition," the group says.

Bottom ash from incinerators may be inert enough to be a substitute aggregate in road building, the guidelines advise, but its inertness "must be established before it is used in this way."

When it comes to the recycling of plastic wastes, there are many problems. A variety of different types of plastics are used, the plastics contain a wide range of additives, and many objects contain plastics as well as other materials. The sorting of plastics may be technically difficult or expensive. The technical guidelines deal with all these issues.

Due to the concern of the Basel Convention Parties regarding what happens to scrap insulated cables during the process of metal recovery, a guideline on plastic coated cable scrap is included for the first time. It demonstrates the difficulties of waste plastics management.

According to the Bureau of International Recycling, in 1997, worldwide over 1.8 million metric tons of insulated wire and cable scrap was generated, containing, on average, about 60 percent metal and 40 percent plastics. The conducting metal in this scrap is primarily copper, although, power transmission cables have aluminium as the conducting metal.

Utilities use insulated aluminium power cable as outside distribution cable, and insulated copper wire for inside distribution. Building, communication, electronics and automotive markets normally use copper as the conducting metal. About 30 percent of the scrap cables exported annually from the United States, Japan and Europe to developing countries are re-used rather than recycled.

Plastic insulated wires (Photo courtesy Freefoto.com) This cable scrap is valuable, mainly because it contains copper and aluminium metal, although the plastic also has value and can be recycled or reused. Cable scrap contains primarily polyvinyl chloride (PVC) or polyethylene insulation and jacketing. The main way of recovering the metal from cable scrap in the developed countries is automated cable chopping in large plants. But in developing countries, environmentally sound but less expensive cable stripping plants are more common, a process with much lower throughput.

"Pre-sorting is the most important element of the environmentally sound management of cables scrap," the technical working group says.

By contrast to the tailings remaining from cable chopping operations, tailings from stripping operations are mostly free of metal and frequently contain only one type of polymer. In the recovery of tailing materials for re-use this has resulted in second generation products. For example, PVC is recycled in pallets or directly reused to manufacture insulation of electric cable, insulation tape, car mats, carpet lining, flooring and footwear.

Again, the guidelines underline, "Open burning is not an environmental acceptable solution for any kind of waste."

Burning in controlled atmosphere furnaces can only be managed in an environmentally sound manner by using state of the art flue gas cleaning which meets strict emission standards. In this process, the energy should be recovered as far as possible, the working group advises.

Since 1969, many cable recovery furnaces have been supplied to metal scrap dealers and several cable chopping companies. More than 700 of these furnaces are in operation worldwide at their peak and still in use now. "Furnaces can be connected to appropriate gas cleaning systems for all plastic, such as scrubbers that remove the hydrochloric acid generated when burning PVC," the technical working group advises. But Greenpeace says that incinerators with state-of-the-art pollution control equipment are formidably expensive. The environmental group points out that once authorities have invested in incineration they often do not have the money to invest in waste reduction. "In this way, incineration directly competes with efforts to reduce and recycle waste."

Plastic trash (Photo by David Humber courtesy National Renewable Energy Lab) "Like many industrial products, plastics pose risks to human health and the natural environment that can be reduced through recycling, re-use, and rigorous disposal procedures," said Klaus Toepfer, executive director of the United Nations Environment Programme. "These new guidelines demonstrate that the Basel Convention is playing a lead role in promoting environmentally sustainable development."

The Basel Convention was adopted in March 1989 after a series of notorious "toxic cargos" from industrialized countries drew public attention to the dumping of hazardous wastes in developing and East European countries.

The Convention regulates the movement of these wastes and obliges its members to ensure that such wastes are managed and disposed of in an environmentally sound manner. Governments are expected to minimize the quantities that are transported, to treat and dispose of wastes as close as possible to where they were generated, and to minimize the generation of hazardous waste at source.

Due to different reporting methods in various countries, it is difficult to produce reliable statistics on the generation and cross-border movements of hazardous waste, the convention secretariat says. It cites statistics provided by 36 nations that are Parties to the convention which show that about 200 million metric tons of hazardous wastes were generated in their countries in 1999.

Currently, 148 countries and the European Community are Parties to the Basel Convention.