Asbestos waste management involving technical aspects
Overview
Asbestos waste management and technical aspects vary from country to country as they adopt and utilize different procedures and policies regarding the management of asbestos waste including the disposal element as an example:
Environmental Protection Agency (EPA) hazardous waste regulations slightly differ than those of HSE Health and Safety Executive and Environment Agency hazardous waste regulations:
In Germany, waste containing asbestos is normally disposed of permanently in special landfill sites or sections thereof. Unfortunately, attempts at large-scale asbestos fiber destruction with concurrent cement matrix recycling have been unsuccessful.
In the Netherlands there are four basic techniques for destroying asbestos fibers, with several intermediate forms.
- Thermal techniques: these techniques are based on the fact that asbestos decomposes at high temperature and hence is no longer carcinogenic. For example, there are techniques for destroying asbestos with ovens, plasma torches or microwave radiation. By adding chemicals or clay, the process can be speeded up and operated at a lower temperature.
- Chemical techniques: with chemicals one can destroy asbestos fibers. There are techniques that work with acids and those that work with bases. Sometimes the process is accelerated by bringing it to higher temperature and/or pressure (there are also chemical processes that generate heat and therefore require cooling). Often an additional purpose is to be able to use organic waste, waste acids from industry or captured CO2.
- Mechanical techniques: the fibers can be broken down by grinding asbestos very finely. For this purpose, special high-energy mills are used, which not only effect physical, but also chemical and chemical transformations, resulting in very fine, non-toxic powder.
- Biological techniques: finally, fungi and bacteria can also break down asbestos. This happens very slowly in nature. With the creation of the right conditions, this process can be fastened considerably. For now, it has been proved that loose fibers of asbestos of the chrysotile type can be broken down in this way.
In certain cases, reuse of asbestos is of secondary importance, another part of the waste stream has the economic value [Editor’s comment: reuse/recycle of asbestos is not recommended from the standpoint of health. The author alludes to this in the below section “Re-use off and later sections]. This is the case, for example, for recycling asbestos containing metal scrap into clean, reusable metal. Finally, in soil contaminated with asbestos, the economic value of asbestos waste treatment does not primarily lie in the reusability of the soil itself, but also in the excavation and remediation costs that are avoided.
Risk aspects: the less asbestos-containing waste is transported and pre-treated (dried, shredded or crushed), the less strict measures are necessary for the protection of employees, local residents and the environment, and the smaller the risks that something can go wrong. In addition, certain technologies may require measures to work safely with aggressive substances, increased temperature and/or pressure.
Potential CO2 footprint: asbestos waste treatment techniques that use relatively more energy have a larger potential carbon footprint (although of course this can be reduced by using energy from renewable sources). For a good comparison, however, this potential footprint must be balanced by what CO2 emissions the product to be reused would have caused if it had been produced in a regular manner. Steel production from ore or ordinary metal scrap requires similar amounts of energy as recycling asbestos containing metal scrap. The same goes for the regular production of cement. The production of less active fillers requires less energy.
Thermal techniques
Closest to (the Dutch) market appears to be the technique for recycling asbestos containing steel scrap in steel melting furnaces. This is a regular steel recycling technique with melting furnaces, in which special measures have been taken for dealing with asbestos containing steel scrap in a safe way. The technology is mature and appears to be sound. There are no indications of lack of administrative and public acceptance. Several other thermal techniques are a little more distanced to the (Dutch) market but could possibly advance (possibly in a few years’ time) if the conditions are right. An important example of this is the technique for thermal denaturation, in which asbestos containing waste is driven (for 75 hours) through a tunnel kiln and is brought to a temperature of 1000 °C, as a result of which the asbestos loses its fiber structure.
The thermo-chemical treatment technique
A combustion technique in which the decomposition of the asbestos (at a temperature around 1200 °C) is speeded up by adding chemicals. However, for this technique some final technical tests must also be passed.
Biological techniques
Biological techniques which aim at accelerating the natural degradation of asbestos fibers by bacteria or fungi are currently still technologically immature. However, soon as this technique is somewhat more under control, further discussions can be expected for in situ treatment of asbestos contaminated soil, and the barriers to entry to the market appear to be very low. Energy consumption and potential CO2 footprint of biological techniques are minimal. However, the safety of working with fungi, bacteria and any additives must be addressed, with guaranteed safeguards put in place.
Chemical techniques
The historical record of chemical asbestos waste treatment techniques is rather poor. It has been known for quite some time that asbestos fibers can be destroyed by attacking them with strong acids or bases. Attempts to apply this principle on larger scale have so far mostly failed because of problems with controlling the risks of the physico-chemical process and the need to neutralize the end-product before it can be reused.
In UK all asbestos products or materials that are deemed ready for disposal are defined as asbestos waste. Asbestos waste also includes asbestos contaminated building materials, tools that cannot be decontaminated, personal protective equipment and damp rags used for cleaning. If in doubt, always treat waste as ‘Hazardous’ or ‘Special’. See below for more details.
England and Wales
Asbestos waste is ‘Hazardous Waste’ when it contains more than 0.1 % asbestos. The Hazardous Waste Regulations 2005 apply. Complete a Hazardous Waste Consignment Note. Contact the Environment Agency for more information in England. Contact Natural Resources Wales for more information in Wales.
Scotland
Asbestos waste is ‘Special Waste’ when it contains more than 0.1 % asbestos. The Special Waste Amendment (Scotland) Regulations 2004 apply. Complete a Hazardous Waste Consignment Note. Contact the Scottish Environment Protection Agency for more information.
England, Scotland, and Wales
All asbestos waste is subject to Schedule 2 of The Control of Asbestos Regulations 2012 and most waste is subject to The Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations 2009 (CDG 2009). CDG does not apply to firmly-bound asbestos – asbestos cement or articles with asbestos reinforcement which do not release hazardous or respirable fibers easily. However, the hazardous and special waste regulations still apply. CDG applies for all other asbestos waste.
Asbestos waste must not be mixed with other waste to achieve below 0.1%
- Waste must be packed in UN-approved packaging with a CDG hazard label and asbestos code information visible
- Double-wrap and label asbestos waste. Standard practice is to use a red inner bag with asbestos warnings, and a clear outer bag with the CDG label, if required
- Avoid breaking up large pieces of asbestos waste. Instead double wrap in suitable polythene sheeting (1000 micron-gauge) and label accordingly
- To transport waste, you need a waste carriers license.
- If you carry waste, use a sealed skip, or a vehicle with the following:
- segregated compartment for asbestos
- easily cleanable
- lockable (it is not good enough to throw sheeting over a standard skip)
- Otherwise, arrange for transport by a registered waste carrier
- Safe disposal – make sure you use a licensed disposal site
- Complete a Waste Consignment Note; keep copies of these documents for three years
- All waste should be double-bagged or double-wrapped in plastic sheeting, with the correct hazard warning signs attached
- Use a lockable skip for large sections of asbestos materials
As part of your waste duty of care, you must classify the waste your business produces:
- before it is collected, disposed of, or recovered
- to identify the controls that apply to the movement of the waste
- to complete waste documents and records
- to identify suitably authorised waste management options
- to prevent harm to people and the environment
If you are not familiar with legislation:
- Use and or seek guidance if you produce, manage or regulate waste.
- For most wastes, you will need to identify if the waste has a hazardous property before you can classify or describe it.
- Seek guidance to explain how to assess if the waste displays a hazardous property and how to classify it.
Waste classification and assessment
Introduction
This explains how to classify a waste and identify its hazardous properties.
You need to classify each waste so you can describe it. The classification:
- must be worked out before the waste is moved, disposed of, or recovered
- must be included on waste documents and records
- determines the controls that apply to movement of the waste
- is needed to identify a suitably authorised waste management option
Examples of the classification of common wastes for England are provided by HSE
Waste classification and assessment
Steps to classify the waste:
- check if the waste needs to be classified
- identify the code or codes that may apply to the waste
- identify the assessment needed to select the correct code steps to assess the waste
- determine the chemical composition of the waste
- identify if the substances in the waste are ’hazardous substances’ or ’Persistent Organic Pollutants’
- assess the hazardous properties of the waste
- assign the classification code and describe the classification code
Check if the waste needs to be classified; if you are unsure seek advice from a competent
person.
The need to ensure the material is waste and needs to be classified.
Nearly all household, commercial and industrial wastes do need to be classified.
- This includes waste from domestic households
- The material does not need to be classified if it is either: not waste, or a waste that is excluded from classification
Construction and demolition wastes containing asbestos
Asbestos is a naturally occurring silicate mineral and exists in several chemical types – for example chrysotile (‘white’), amosite (‘brown’) and crocidolite (‘blue’) – either in a bonded or fibrous form.
- The fibres are very fine, less than 3 microns in diameter and respirable into the lung passageways where they can lodge indefinitely and penetrate tissue
- All forms of asbestos are classified the same way in a harmonised entry in the classification and labelling inventory as:
The assessment of asbestos containing waste considers both the presence of asbestos as:
- fibres that are free and dispersed, and
- identifiable pieces of asbestos containing material
If the waste contains fibres that are free and dispersed, then the waste will be hazardous if the waste contains 0.1% or more asbestos.
If the waste contains any identifiable pieces of suspected asbestos containing material (ACM), they must be assessed as set out below. This would also apply to any dispersed fibres produced by deliberately breaking up such identifiable pieces.
Where the waste contains identifiable pieces of ACM,
- any particle of a size that can be identified as potentially being asbestos by a competent person (if examined by the naked eye), then these pieces must be assessed separately. The waste is hazardous if the concentration of asbestos in the piece of ACM is 0.1% or more
- the waste is regarded as a mixed waste and classified accordingly (see example 1 for advice on how to apply list of waste codes to mixed waste). The following waste codes should be assigned to the asbestos waste as appropriate:
- 17 06 05* Construction material containing asbestos MH
- 17 06 01* Insulation material containing asbestos MH
- 17 06 05* would normally be used in preference to 17 06 01* for the asbestos in asbestos contaminated soil and stones
The most relevant asbestos wastes are listed in the table below (entries in red [KT1] and marked with an ‘(A)’ are absolute hazardous waste and entries in blue and marked with an ‘(M)’ are mirror entries:
