What to do with hazardous material in a Circular Economy – Temporary storage recommendations
Situations may occur where it is not immediately practicable to recycle hazardous e-waste items nor economically viable or legally possible to export the material to another location. Such situations may arise for the following reasons, for example:
- Lack of suitable facilities locally/nationally to treat hazardous items;
- Insufficient quantity to warrant transport to a treatment facility;
- Hazardous items which have negative value and there is insufficient funding to pay for treatment; and
- Market/regulatory barriers which can frustrate attempts to access treatment facilities, particularly if export is the only option.
Hazardous e-waste items that cannot be re-used or recycled should be managed in a responsible manner. It should be recognized that the treatment of hazardous e-waste is a highly specialist industry that requires very high levels of environmental controls to be in place if it is to avoid significant pollution further down the line. Its treatment (or disposal) should not, therefore, be undertaken in an ad-hoc manner without the proper controls being in place. A government has a significant role to play in fostering, developing and regulating such an industry as a critical part of national infrastructure. Nonetheless, in many nations, this infrastructure is not currently developed and the management of hazardous e-waste can be problematic, at least in the short term.
1. Temporary Storage
Storage is a temporary holding of the wastes while arrangements are put in place for its proper treatment or disposal. It is not a solution for waste to be stockpiled with no long-term solution, as this has the potential to cause environmental harm to the site and represents a significant financial liability for the holder. However, prior to appropriate facilities becoming accessible temporary storage might sometimes be necessary, and may be preferable to the uncontrolled dumping of the waste.
There are two main types of storage: on-site and off-site. On-site storage is within the premises of the waste generator – which for e-waste could be at the site of partial disassembly where certain components cannot be treated – while off-site storage removes the wastes from the premises on which they were generated to be kept centrally, as part of planned larger waste management system. Both types of storage are pending the treatment or disposal of the wastes.
Storage should be for as brief a period as possible, whether it be on or off-site, and suitable storage locations with appropriate containers should be used. The most important provisions to ensure this include:
- the appropriate physical design of the storage area;
- the correct labelling of the waste containers;
- clear signage for the storage area;
- appropriate duration of storage; and
- Employee training.
2. Thermal Treatment
The uncontrolled combustion of any e-waste item should be avoided. This is acutely important with regards to hazardous e-waste, as the environmental and health risks posed by inappropriate combustion can be severe. Consequently, unless thermal treatment can be conducted by dedicated treatment plant, with proper and regulated emissions control systems then it should not be considered as an option for e-waste.
Thermal treatment, in general, is only suitable for ‘organic’ materials e.g. Plastics from e-waste housings, and is not suitable for many other types of e-waste e.g. metals. Consequently, thermal treatment is only suitable for e-waste that has been processed, disassembled and has had the inorganic contaminants (e.g. metals) removed for recycling in other ways.
Such e-waste material can be treated in dedicated high-temperature hazardous waste incineration facilities, and this could be an option for certain types of e-waste plastics, including those containing Brominated Flame Retardants (BFRs), or oils containing PCBs which can be found in some older industrial power transformers. These facilities typically operate at temperatures of 1,150 oC or higher and have advanced flue gas treatment systems. However, such facilities are highly specialized and comparatively few in number around the world. Consequently, it is likely that many countries will not have access to such facilities in-country. The costs of such treatment are high, and the export of such materials to facilities elsewhere is tightly regulated under the Basel Convention.
It is also possible, however, for some industrial processes which use wastes as fuel, and it is conceivable that these could be suitable for certain types of e-waste. These include industries such as steel, glass and cement manufacture, but of these, cement kiln use is the most likely. Many countries will have a national infrastructure of cement kilns and the use a cement kiln for the thermal treatment of certain hazardous organic wastes can be technically and environmentally sound.
Cement kilns have been used extensively for many years for hazardous wastes treatment. As cement production is very energy intensive (40-65% of total cost), the saving in primary fuels makes the burning of organic wastes attractive from the kiln operator’s point of view. The typical combustion conditions include temperatures in the range 1,350-1,650oC, thus, complete destruction of organic pollutants is assured.
It is important to realize that any industrial user of e-waste as a fuel will not be able to use ‘raw’ e-waste. It has already been stated that only e-waste that has undergone some form of pre-processing to remove inorganic contaminated material would be potentially suitable. However, it is almost certain that the materials will have to be further processed to a consistent Solid Recovered Fuel (SRF). The compatibility of SRF in cement kilns is governed by several factors, such as thresholds for key inorganic contaminants like Chlorine and metals such as Cadmium, and these would have to be demonstrated as being complied with before an industrial operator would consider its acceptance.
The use of SRF by industrial users has been studied in detail and standards have been suggested for key properties to establish a common understanding on its suitability for different end-users. Detailed information has been published by the European Committee for Standardization in: Key Properties on Solid Recovered Fuels to Be Used for Establishing a Classification System; CEN/ TS 15508:2006, which provides a useful reference.
The thermal recovery of certain hazardous e-waste fractions is therefore technically feasible in some cases. However, it is a highly technical field which requires experienced operators in order to effectively control the risks. Such conditions are likely only to be satisfied in mature industries which have the analytical and operational controls in place to implement it safely, and will certainly be high profile infrastructure operators with a national or international profile. If a thermal facility does not conform to this highly developed profile it is unlikely that it represents a justifiable outlet for hazardous e-waste.
Landfills form part of every integrated waste management system. However, only properly engineered and operated landfills provide adequate levels of pollution control, this is especially true with respect to the disposal of hazardous E-wastes. The disposal of hazardous E-waste in uncontrolled dumpsites is not acceptable.
The landfilling of hazardous waste items, of any sort, has significant environmental risks. Research into such landfills and high profile examples of the health effects on populations living close to such sites has raised the issue to one that is considered on an international level. The United Nations Environment Programme (UNEP) in conjunction with the International Solid Waste Association (ISWA) have attempted to provide guidance on the establishment of suitable facilities with their Training Resource Pack for hazardous waste management in developing countries (UNEP, N.D.)
Landfilling hazardous materials is a very specialist operation – this puts it beyond the typical organization whose ‘core business’ is simply the management of e-waste. If performed in a responsible manner it requires significant engineered infrastructure and financial provisions to be in place for the very long term storage of such wastes. Again, if these requirements have been created and fulfilled, these are likely to be high-profile sites of national importance within the waste industry for any country. Any other approach is likely to cause severe problems down the line.
In the absence of specific hazardous waste landfills, some ‘transitional’ technologies may be suitable in the short-term for some areas, for some wastes. The concept of transitional technologies is that they are a ‘stepping stone’ on the way to the evolution of a state-of-the-art system for waste minimization, recycling treatment and disposal. These transitional technologies may include: co-disposal of selected waste with domestic wastes in properly controlled municipal solid waste landfill sites; and cement waste solidification at a landfill site. Again, this is a highly complex issue that requires consideration of specific circumstances and the UNEP/ISWA report mentioned above provides some guidance on these issues.
From an e-waste management perspective at a local level, if the infrastructure described above is not in place and operated by a robust and well-regulated organization then landfilling of non-recyclable hazardous e-waste should be avoided. If wastes have no immediately accessible outlet then temporary storage of the hazardous items must be considered to facilitate the later identification and implementation of suitable outlets for the material.