Wastes containing POPs and PCB

transformer stationClick to enlarge
Transformer: Transformers formerly contained PCBs as a coolant
Source: Cornelia Wohlrab / Fotolia.com

Persistent organic pollutants (POPs) are a worldwide problem. PCB, which is a POP, has not been used in Germany for years and only occurs in certain wastes.

Table of Contents

 

POP wastes

Various international conventions have been concluded because of the hazardous properties of POPs. The Stockholm Convention on Persistent Organic Pollutants is an international convention aimed at ending or restricting POP production, use and emissions. The Convention calls for either systematic elimination of a particular substance (included in Annex A) or restrictions on its production and use (included in Annex B). Wastes that contain POPs or that have been contaminated by them are to be disposed of in such a way that, “the persistent organic pollutant content is destroyed or irreversibly transformed so that they do not exhibit the characteristics of persistent organic pollutants or [are] otherwise disposed of in an environmentally sound manner when destruction or irreversible transformation does not represent the environmentally preferable option (...).”

Regulation (EC) No 850/2004 incorporates these fundamental requirements and further specifies the words "otherwise disposed of in an environmentally sound manner".
The specific properties of POPs necessitate specific disposal techniques that meet the aforesaid requirements, which are described in greater detail in general (POP) and specific (e.g. PCB) technical guidelines that were elaborated within the Basel Convention. The techniques mainly used in Germany are underground storage, as well as high temperature incineration.

 

PCB-containing devices in Germany

Initially produced on an industrial scale in 1929, due to its physical and chemical properties PCB soon came into wide use as a coolant and insulation material in the electronics industry, as a hydraulic fluid in the machinery industry, and as a heat transfer fluid in many different industries (so called contained use). It was also used as a plasticizer and flame retardant in paints, varnishes, adhesives, sealants and packaging materials (so called open use).

Thus PCB became an extraordinarily successful technical application that has resulted in widespread application. The fact that PCB is also toxic, enters the food chain and can potentially spread over great distances (via emissions) was discovered much later, with the result that PCB was widely disseminated in the environment, largely through open use and improper waste management. Industrialized nations eventually began enacting laws initially aimed at monitoring PCB use, followed later by statutory limits on its use and finally total bans on PCB use. Such laws were enacted in Germany in 1989 by the PCB-, PCT-, VC-Prohibition Ordiance.

In Germany, virtually all PCB from electronic devices has been disposed of, with the exception of PCB-containing sealants and paints in cases where constructions are rebuilt or torn down. PCB detection and disposal are governed by instruments such as individual technical guidelines by the Federal States (Länder). In recent years, a number of additional substances have been classified as POPs under the Stockholm Convention, including certain brominated flame retardants (e.g. tetra-, penta-, hexa- und heptabromodiphenylether, as well as Hexabromocyclododecane). The disposal of wastes containing these substances still need some clarification.

 

Legal framework

Directive 96/59/EC requires the member states to compile inventories of equipment containing more than five liters of PCB. According to the directive, “PCB” also include polychlorinated biphenyl methanes (PCDM) as well as any mixture containing a total of more than 0.005% by weight (i.e. more than 50 mg/kg) of these substances. According to the directive, equipment containing PCBs means any equipment containing PCBs or having contained PCBs (e.g. transformers, capacitors, receptacles containing residual stocks) that exceed the mandated limit values after the equipment in question has been decontaminated. With special permission, operation of such equipment was allowable in Germany only until 2010. Directive 96/59/EC was transposed into German law via the PCB/PCT-Waste Ordindance of 26 June 2000.

According to Regulation (EC) No 850/2004PCBs belong to substances whose production, placing on the market and use in preparations or as constituents of articles is prohibited.

The POPs Regualtion lays down the disposal processes for wastes containing PCB. Unlike other wastes containing POPs, the use of wastes containing PCB as fuel or for any other heat generation purpose is prohibited (recovery operation R1). Metal recovery from such wastes (recovery operation R4) is allowable under certain circumstances. Disposal operations D9 (physicochemical treatment) and D10 (incineration on land) are allowable, provided that the PCB content is “destroyed or irreversibly transformed.” Pretreatment for purposes of prior sorting and separate disposal of PCB content is allowable. Regulation (EC) No 850/2004 Annex 5 lists those wastes that are allowed to be stored longterm, to remove them permanently from the biosphere (in Germany only underground storage). However, the regulation bans permanent underground storage of PCB containing equipment (such as transformers and condensers) which has been practiced in Germany for a long time. Such equipment must now be either decontaminated (transformers and large condensers) or incinerated (small condensers).

The disposal methods currently used in Germany for waste containing PCBs will be described in the following.

Underground storage (underground landfill)

In the Three Federal States (Länder) of Baden-Württemberg, Hessen, and Saxony-Anhalt, underground storage facilities are operated in-salt fromations where storage of waste containing PCB is allowed. The concentration limits mentioned in Regulation (EC) No 850/2004 Annex 5 do not apply to permenent underground storage facilities. Contaminated electrical equipment was stored in such facilities until the practice was banned in 2004. Some transformers were removed from underground storage facilities and decontaminated between 2004 and 2010.

Storage on landfill sites

Storage of waste containing PCBs exceeding the Regulation (EC) No 850/2004 Annex IV concentration limits on landfill sites (class 0, I, II and III facilities) is prohibited (DLandfill Ordiance section 7).

Thermal treatment (hazardous waste incineration facilities)

Germany’s hazardous waste incineration facility capacity is around one million tons annually. However, only a portion of this capacity is usable for the incineration of waste containing PCBs, since by law only a portion of the capacity of these facilities may be used for such waste. The exact amount depends on waste PCB content and the type of waste involved (solid, liquid, paste, or in receptacles), as well as the facility configuration, including its waste gas cleaning systems. However, up to three percent of the capacity of such facilities can be used for highly contaminated waste, without occasioning any problems. Waste with relatively little PCB contamination (up to around 50 ppm) can be incinerated in other types of licensed waste incineration plants such as municipal waste incineration plants.

Breakdown and decontamination (pretreatment)

During the breakdown process, the various materials (steel, sheet metal, copper) are recovered after oil containing PCBs has been removed. The components containing PCB are high-temperature incinerated.