Plastic Waste Disposal Guidelines Adopted

Experts from some 100 governments meeting in Geneva, Switzerland, 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 that produces environmental hazards that extend far beyond the burning site.

The burning of PVC plastics produces persistent organic pollutants that circulate globally and have been associated with adverse effects in humans.

The new technical guidelines address concerns that some developing countries lack the legislation and facilities to cope with piles of plastic wastes of all kinds.

To develop a standard, a group within the Basel Convention put together technical guidelines. The Technical Guidelines for the Identification and Environmentally Sound Management of Plastic Wastes and for their Disposal were put together last week by the Technical Working Group of the Basel Convention on the Control of the Transboundary Movements of Hazardous Wastes and Their Disposal.

The group will go forward for final adoption to the 6th meeting of the Conference of the Parties to the Basel Convention.

"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."

"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."

Greenpeace, which submitted comments in the public process that resulted in the 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 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 technical working group acknowledges that fly ash from flue-gas cleansing usually contains materials such as heavy metal compounds that 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.

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. This cable scrap is valuable, mainly because it contains copper and aluminum metal, although the plastic also has value and can be recycled or reused. Cable scrap contains primarily polyvinyl chloride 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."

The Basel 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.

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