A light at the end of the tunnel

The challenges of lamp recycling On 20 February this year, the Australian government announced plans to phase out inefficient light bulbs. Malcolm Turnbull MP commented: ‘We have been using incandescent light bulbs for 125 years and up to 90% of the energy each light bulb uses is wasted, mainly as heat … The more efficient [lamps], such as the compact fluorescent light bulb, use around 20% of the electricity to produce the same amount of light’. This move is being replicated to varying extents globally, and although it may have a positive impact in terms of energy efficiency, it is also prompting a growth in fluorescent lamp sales. Millions are sold worldwide each year, and millions have to be disposed of when they cease to function. Since fluorescent lamps contain the hazardous neurotoxin mercury, they are increasingly being treated as hazardous waste. However, while the technology for safe disposal of waste lamps is evolving, a global consensus has yet to be reached on what is the most appropriate route for lamp disposal. A significant proportion of companies and other stakeholders in this industry clearly support centralized, whole-lamp recycling as the most sustainable route. But on-site crushing also continues to attract investment, whereby the crusher is mobile, working to increase the number of lamps that can be transported ‘back to base’. In this article, Waste Management World treads carefully through this minefield of broken glass, strong opinions and - most significantly of all - mercury waste. Mercury: a global concern Mercury is considered such a serious problem because it does not smell and vaporizes easily, so cannot be readily detected. When absorbed into the body, it can accumulate and damage various organs and the nervous system. Fluorescent lamps contain a small quantity of mercury-bearing phosphor powder. According to Lampcare UK, a company that specializes in lamp disposal, mercury from just one fluorescent tube can pollute 30,000 litres of water beyond a safe level for drinking. The risks associated with inadequate disposal of lamps are therefore significant. In November 2006 anti-mercury groups made a call for world governments to ban mercury exports and reduce global mercury pollution. In particular, they were hoping for a formal announcement during a recent meeting of the United Nations Environment Programme. While a binding, global target was not agreed during this meeting, some positive steps were taken. And these follow closely on the heels of a proposal from the European Commission last autumn to ban all European Union exports of mercury from 2011. Cumulatively there is clearly growing international momentum to reduce the use of mercury in manufacturing and trade. Developments in disposal In order to gain a better understanding of what is involved in fluorescent lamp recycling, I visited a dedicated recycling plant in Harlow, UK, operated by Lampcare. Lamps ready for processing in one of MRT’s end cut machines at Lampcare’s facility in Harlow, UK Click here to enlarge image The Harlow plant went on line in 2004 and currently employs approximately 20 operatives, plus a core management staff. It also employs six drivers who cover the entire southern England, driving 26-tonne rigid vehicles, each containing a demountable forklift and sleeper cab. The vehicles head out of the depot on Monday each week and can be ‘on the road’ throughout the week, returning fully loaded on Friday. This means that the main site looks busiest on Monday or Tuesday, after the vehicles have unloaded at the end of the previous week. I visited the site on a Tuesday and it appeared to be overflowing with lamps. Supply, it seems, is not an issue! This is hardly surprising since Lampcare’s ethos is to make recycling as easy as possible for the client. With this in mind, it provides a container to the client (often in the form of a 300 mm diameter tube, 8 ft or 2.4 m in length) and is happy for the client to insert lamps of different types within the same container. Furthermore, clients can place old lamps in the above-mentioned tubes (or larger bulk containers) wrapped in cardboard packaging or stuck together with insulation tape - a common practice used by maintenance staff swapping new lamps for old. The technology There are four main types of lamp processed at the Harlow facility. These are: linear, fluorescent tubes compact fluorescent lamps (CFLs) sodium lamps high-intensity discharge (HID) lamps. Generally speaking, there is a different process for each type of lamp recycling. And in each most cases, Lampcare relies on technology supplied by MRT Systems AB - a Swedish company specializing in mercury recovery. There is insufficient space in this article to detail each of the four processes, but it is perhaps worth touching on how most of the linear fluorescent tubes are handled, which comprise the vast majority of the lamp waste running through the plant. Linear tubes are processed using an ‘end cut machine’ (ECM). As the name implies, this technology cuts both ends off the lamp, thus removing the leaded glass that connects the main tube with its aluminium caps. After the ends are cut off, the phosphor powder is blown off for subsequent distillation (see below) and the residual material is crushed and automatically sorted. The ECM processes lamps that are either 6 ft or 8 ft in length and can handle in the region of 5000 lamps per hour. Mercury distillation Distillation of the mercury from the phosphor powder tends to take about 16 hours and occurs by heating the powder to 800ºC. The mercury evaporates, leaving an inert phosphor residue that can be used in the building sector. The mercury is subsequently cooled, condensing to form approximately one thimble-full of mercury during one year’s full-time operation. While the quantities of mercury generated are very small, health and safety remains an important concern. Taking Lampcare as an example, it undertakes quarterly urine tests on its staff to ensure there is no mercury getting into people’s systems. The company also undertakes quarterly ‘Jerome analyses’ to check air quality. When handling lamp material, the employees wear boots, a disposable mask and goggles. The company’s version of a vacuum cleaner is used to clean up broken lamps lying in crates or on the factory floor. A policy of zero waste Before closing this section, it is worth returning to the emergence of compact fluorescent lamps (CFLs) mentioned by Mr Turnbull in the opening paragraph. When processing CFLs, there are two key differences. First, such lamps do not conform to a uniform shape. And two, they contain plastic fittings. This means that the processing technology is adapted to cope with different shaped products. In addition, a plastics waste stream is generated, leaving Lampcare to source external polymer companies that have a demand for such plastic by-products. This type of liaison exemplifies the company ethos - to adopt a ‘zero landfill’ policy. And this is a significant goal, bearing in mind it handles in the region of 10 million lamps per annum on the Harlow site alone. What is the alternative? The alternative to whole-lamp recycling is pre-crushing. The perceived advantage of this strategy is that it reduces service costs and reduces lamp volume by 80%, so five times as much can be carried in one load. This means that the costs of transportation - in both financial and environmental terms - can be reduced. One UK company which supports mobile crushing is Balcan Engineering. It won a Queen’s Award for Enterprise in 2006 in recognition of its outstanding achievement in innovation. The Balcan recycling plant in Lincolnshire, UK was commissioned in 2002 and can process approximately 750 tonnes of waste lamps per annum. In addition, Balcan operates a fleet of vans, each fitted with an electrically operated crusher. This offers scope for on-site crushing. The mobile crushers use a fan-assisted filtration unit to draw off the dust during crushing. In this way the machine operates at negative pressure. The extractor is positioned in the chute because fluorescent tubes can inadvertently burst anywhere along their length so it is essential to capture the resultant dust as it is generated. Balcan has added a spring-loaded sealing plate to their mobile crushing equipment which is designed to prevent escape of mercury vapour during the crushing process. Debris from the crushers discharges directly into strong plastic sacks holding an average of 25-27 kg of debris (see photo on the next page). And the recycling operation -which is designed to accept dry debris only - begins when the debris sacks are emptied into a hopper. From the hopper the debris is conveyed into a rumbler, which comprises of a large diameter cylinder with a number of fins fitted inside along its length. The cylinder is fitted in a long rectangular casing. Each end is fitted with a rectangular plate to close off the casing and to seal the cylinder. Holes are made in these plates to allow material to be loaded at one end and to discharge at the other. An electric motor fitted at one end drives a shaft going through the cylinder and rotates it at the required speed. As it rotates it carries up the lamp debris on its fins. The debris then cascades off and breaks into smaller pieces. The agitation of pieces knocking and rubbing against each other removes much of the adhering powder from the surface of the glass. The powder then dusts up and is drawn off by air extraction filters. The cleaned debris then discharges at the other end where the aluminium end caps are separated from the glass debris and collected separately into self-tipping mini skips. These in turn are emptied into a much larger skip capable of holding 25 tonnes of material. Click here to enlarge image The aluminium is sold to a metal merchant and the glass is collected for use in the construction industry. The mercury-containing phosphor powder from the filters is collected in 45-gallon drums which are sent for processing by a specialist distillation company named Quicksilver in Berwick-upon-Tweed, United Kingdom. The focal point of the debate While Balcan is an award-winning company, its strategy - as an exemplar of mobile crushing - is controversial. Pre-crushing attracts strong criticism from those who favour only whole-lamp crushing. This appears to stem from two primary concerns: First, there is a basic concern about ‘what happens next?’ - i.e. having crushed the lamp on-site, what happens to the material once it is transported away. Verifying the audit trail is potentially more difficult when mercury disposal is handled by a third party. Secondly, some stakeholders are also worried about the increased risk of fugitive emissions from mobile plants that occur during the crushing process (see box on drum-top study on the previous page). Naturally, steps in the design of the mobile equipment can be taken to minimize the risk of such emissions; but fundamentally one may perceive greater scope for fugitive emissions when using mobile plant. My trip to Lampcare also highlighted a potential concern that mobile plants are limited in the range of lamps they can process. As lamp design diversifies, with more CFLs entering the waste stream, will mobile crushers be able to process emerging products that contain different materials in both solid and gaseous forms? A grey area? At this point I should highlight that it would be over-simplistic to paint this story in only black or white. The basic concept behind reducing transport demand does offer theoretical advantages in both environmental and economic terms. And the likelihood of bulbs breaking in transit has already prompted companies such as Lampcare to accept a proportion of broken bulbs into its waste stream. Interestingly, MRT Systems AB - a dominant company in this sector, which supplies technology to Lampcare in the UK - also promotes a crusher in addition to a broad range of other mercury recovery technology. Click here to enlarge image Over the years, MRT has developed different crushers for different lamp types (straight fluorescent, HID and CFLs). To minimize emissions, its crushers have sub-pressure slots preventing dust and mercury vapour from escaping, and the exhaust air passes through a combined cyclone/dust filter and carbon filters. Christer Sundberg, President and CEO of MRT, comments as follows: ‘Pre-crushing can be an alternative in areas where long distances or other circumstances make it difficult to transport. The concept with satellite units and second stage hub facilities, where the actual separation and demercurization takes place, has been promoted by MRT for many years. After the WEEE directive implementation, it is extremely important that the second-stage separation of the crushed material is performed by well-proven technology that enables the manufacturers to comply with the producers’ responsibilities.’ Who to turn to? Naturally, waste managers may be faced with some concerns when considering how best to proceed and unsurprisingly, many turn to policymakers for guidance. In the UK the management of electronic and electrical waste (WEEE) is evolving rapidly, primarily in response to the EU WEEE Directive. And the debate on lamp disposal remains active in its waste industry. On-site crushing of lamps previously fell under UK waste management licensing exemption, meaning that companies did not need to apply for a licence to undertake this operation. (Note that this does not cover mercury processing - only the lamp crushing process.) Looking at recent developments, the Waste Electrical and Electronic Equipment (Waste Management Licensing) (England and Wales) Regulations 2006 came into effect on 5 January 2007. This continues to exempt the crushing of fluorescent lamps from the need to have a waste management licence provided that there is no risk to human health or the environment, and that any site at which the lamps are crushed is registered with the Environment Agency. Therefore there remains scope for mobile crushing in England and Wales on the condition that the technology is proved to be safe. And this is the key question. While Balcan states that emissions from its units comply with all legislative requirements, it seems likely that any resolution to this debate will require further independent research. In the US, a similar debate has also been taking place. Recently the Environmental Protection Agency concluded a study focusing on testing ‘drum-top’ crushing equipment (see box earlier in the article), a different type of mobile technology. Conclusion The discussion on how to handle waste lamps is not over, with strong opinions for and against pre-crushing. A clear outcome in this article is that fluorescent lamps are hazardous and a secure disposal solution is imperative. It is also clear that the challenge facing recycling companies operating in this sector is growing. Lampcare has invested £6 million (€9 million) in a new plant in Huddersfield, UK. This is dedicated to processing all forms of WEEE and is intended to include lamp recycling technology. This will be the company’s third plant in the UK - and is expected to be its most technologically advanced. Such investment is crucial, bearing in mind that while linear fluorescent tubes currently dominate the marketplace, it looks as though the market for CFLs and HID lamps is growing. And other new lamp designs are emerging, including xenon car headlamps, shatter-proof lamps that are plastic-coated, and lamps containing beryllium, thallium, tantalum and even krypton. For the comic fans amongst our readers, one might say that a ‘superhuman’ effort is needed to keep up with this changing marketplace. Guy Robinson is Commissioning Editor of Waste Management World.e-mail: wmw@pennwell.com EPA’s drum top crusher study by Greg HelmsThe US Environmental Protection Agency (EPA) recently released a study of several lamp crusher devices. Drum top lamp crushers (DTC) fit on the top of a 55 gallon (208 litres) steel drum and, when a lamp is inserted through the feed tube, crush the lamp into the drum below. These devices are used to reduce the volume of waste lamps, so as to improve storage and handling and reduce shipping costs of waste lamps to make it easier to recycle them. Most DTCs currently sold in the US are designed to contain most of the mercury released during crushing. To do this, they operate at negative pressure (using a vacuum pump), and particulate and activated carbon filters are used to remove mercury from the exhaust air. The EPA studied the performance of four such devices. The objective of the study was to evaluate the ability of the four DTCs to contain the mercury released from crushed lamps in terms of preventing worker exposure to adverse levels of airborne mercury resulting from the operation of the devices. Approximately 5500 lamps were crushed by three of the four devices over the course of the six-month study. The study found that all of the DTCs tested release some mercury in use. Three of the devices, when operated optimally, generally maintained average mercury exposures below US occupational exposure limit values while lamps were being crushed. However, when filled drums were exchanged for new drums and during malfunctions (e.g., when lamps broke as they were being fed into the devices and when a seal was missing), mercury air concentrations often exceeded the occupational exposure limit values for short periods of time. (The occupational exposure limit values of 0.1 mg/m3 and 0.025 mg/m3 were used as points of reference only. The measured mercury concentrations were either instantaneous measurements or were averages of one- to three-hour time periods; eight-hour time-weighted averages were not calculated from the data.) The fourth DTC device was eliminated from the study part-way through because it failed to contain mercury and caused mercury exposures up to nine-fold higher than the US regulatory occupational permissible exposure limit, even though only low-mercury lamps, containing less than 5 mg/kg mercury, were crushed by the device. Other findings of the study include: Because mercury vapour is colourless and odourless, DTC operators had to rely on mercury vapour analyzers in order to be aware of mercury releases and exposures that occurred during the study. Mercury vapour analyzers can be used to measure airborne mercury, but cost several times what the DTC itself costs. Ensuring compliance with exposure standards may be difficult to verify cost-effectively. Performance of DTCs may change over the lifetime of the device and under varying environmental conditions. Two of the devices showed a significant decrease in their ability to contain mercury after being used to crush eight drums of lamps. Changes in the test environment, especially changes in temperature, also may have affected device performance. The complete study report can be downloaded at: www.epa.gov/epaoswer/hazwaste/id/univwast/drumtop/drum-top.htm - Greg Helms is Acting Chief of the EPA’s Hazardous Waste Generator and Characterization Branch