Table 1. Summary of European National Battery Legislation, May 2001
Table 1. Summary of European National Battery Legislation, May 2001
environmentally inert, the primary battery producers were disappointed by some Member States' interpretation of the European Directive. They argued that primary alkaline-manganese and zinc-carbon batteries could safely be disposed of in landfill and therefore legislation to collect and recycle all batteries was unnecessary. This argument was based upon the conclusions of several international studies. These included the Institute of Risk Research study, University of Waterloo, Ontario, Canada1 (1992) and ongoing landfill studies undertaken at the Fukuota University in Japan2.
The Canadian report concluded that dry-cell batteries do not represent a concentrated source of heavy metals in municipal solid waste and their disposal by landfill or incineration poses insignificant risk to human health. Furthermore they concluded that separate collection, storage and disposal of most household batteries produced more significant health related problems and that recycling of primary batteries was neither necessary nor needed.
The Fukuota University study has charted the corrosion rate and mercury leaching potential from batteries buried in typical landfill conditions. The findings showed that after 9.5 years, the maximum loss of mercury from the battery containing test sites was 0.062% of the initial mercury content. Concentrations of mercury within leachate were measured between 0.0001 mg/1 to 0.00035 mg/1, significantly lower than the 0.0005 mg/1 environmental standard.
However political motivation frequently exceeds technical argument. Consequently the battery industry set up a working group under their european trade association, Europile (later to become the European Portable Battery Association - EPBA), charged with investigating collection and recycling of post consumer batteries in Europe. It quickly became apparent that if recycling of primary batteries was to proliferate across Europe, insufficient facilities and capacity were available to meet the anticipated demand. In the early 1990's, only two companies, both based in Switzerland, offered recycling of alkaline-manganese and zinc-carbon batteries. After investigation, the working group concluded that neither of these companies offered economically viable and sustainable solutions, as they required either large subsidies from Government or offered recycling at prohibitively high cost.
A significant proportion of the cost of these two operations resulted from the need to capture and treat mercury. But since zinc-carbon and alkaline manganese batteries were now free of added mercury, processes concentrating on treating mercury-containing batteries were considered to have a limited future.
With the aid of the international consulting group Arthur D. Little, the industry concluded that, once mercury was no longer added to primary batteries, the most effective and environmentally sound method of recycling them would be to utilise existing infrastructure within the metals industry. Recycling of other post consumer goods such as paper, aluminium cans, steel cans and glass bottles are regularly cited as examples of this integrated approach.
This approach was only possible if the collected batteries could be guaranteed to be below 5 ppm of mercury. However, under the existing Battery Directive, 91/157/EEC, batteries were able to be imported into the European Union which still contained up to 250 ppm of mercury. These imported batteries threatened the viability of the integrated metals industry approach.
Consequently the battery industry approached the European Commission with a proposal for a two stage approach to the issue of collection and recycling of primary batteries. This 'two step plan', proposed that if the European Union legislated for a ban on importation of primary batteries containing any added mercury, (step one), then cost effective and environmentally sound recycling of these batteries could commence four years later, (step two). This four year delay was necessary in order to allow the batteries sold before legislation to pass through the waste stream. This approach was approved by the European Union and adapted into law through a technical adaptation, 98/101/EEC, to the Battery Directive, which came into force on January 1st 2000.
A revision to this Battery Directive has been proposed and is currently in the stage of inter-service consultation within the European Commission. The key proposals within this revision are as follows:
- A marketing ban on all consumer nickel cadmium batteries from the 1st January 2008.
- All the standard size consumer batteries to be marked with a crossed out dustbin symbol on the battery label itself. This will include D, C, AA, AAA and 9V size batteries.
- All battery types to be collected separately from other wastes. A collection targets of 75% is proposed.
- By the end of 2004, all collected batteries must be recycled with a recycling rate of 55% of materials contained within them.
- Member states are left free to define the responsibilities under this Directive. They are also free to employ economic instruments or deposits if they so wish.
The battery industry world-wide supports battery recycling so long as it is effective, environmentally sound and cost effective. The european battery industry, through the European Portable Battery Association, the EPBA, has voiced opposition to these proposals because it feels that they will not meet these aims. A huge financial burden would be placed on the battery industry in Europe in an attempt to reach a collection target which is unachievable. This collection target is also likely to create additional environmental burden rather than reduce it. Both of these issues are discussed further in this chapter.
• Methods and Organisation of Battery Collection
The method of battery collection and economic instruments employed to finance the programmes differ from country to country. The driver for each system is the national legislation and in particular who is given responsibility for the collection and financing. Today, seven countries have battery collection schemes which impact primary batteries. These are Austria, Belgium, Germany, France, the Netherlands, Portugal, Sweden, and Switzerland. Belgium is the only country who pass the full responsibility for collection sorting and recycling, as well as publicity and awareness campaigns on to industry. Both Sweden and the Netherlands leave the responsibility for collection in the hands of the municipalities. All of the other countries share the responsibility for collection jointly between retailers and municipalities.
All of the countries, with the exception of Sweden and Switzerland, will rely on industry to take responsibility for the waste management of the batteries. Sweden relies on the municipalities for waste management and Switzerland gives this responsibility to the recyclers themselves.
Under the existing EU Directive, 91/157/EEC, no specific collection target is set. However some individual countries have imposed their own collection target.
Belgium had a collection target of 75% for 2000: this was not met. Consequently the belgian government have revised their target to 60% of sales by 2002, rising to 65% by 2004. The Netherlands have a collection target of 90% by 2004. These very high collection targets result in spiralling costs for the organisations with responsibility for collection. This is because a great deal of money needs to be spent on publicity and awareness campaigns to encourage the general public to return spent batteries. There is little evidence to suggest that these high collection targets are achievable.
Two distinct financial management schemes can also be identified. The governments of Belgium, Sweden and Switzerland each define an environmental fee which is added to the price of every battery sold in order to finance the collection and recycling operations. The remaining countries pass financial control onto the producers and importers of the batteries, who are then responsible for recovering their costs from the market through sales of new products.
In each of these countries, the battery industry has implemented collection and recycling associations, NCRA's, on behalf of the manufacturers, importers and retailers, who are impacted by the necessity to collect and recycle. Depending on national law, they are either in the form of an association, a federation, or a company. Each of the NCRA's is operated on a non-profit basis. It is not a legal requirement for any company or organisation with responsibility for collection and/or recycling to be a member of one of these NCRA's. Consequently in some countries, competing organisations have been set up to collect and recycle batteries. These are independent of the battery industry and generally profit orientated.
In Germany, the battery decree places specific requirements on the trade, municipalities and end users. Both the trade and municipalities must take back used batteries from the consumer free of charge. Furthermore the distributors are also obliged to notify customers that this is the case. Producers and importers of batteries are required to take back the returned batteries from these collection centres free of charge. They are also responsible for equipping the retailers and municipalities with suitable collection containers. The decree even places a legal obligation on the consumer to return spent batteries to one of these collection facilities.
In 1998, the battery industry set up an organisation with responsibility for the collection of all batteries named Stiftung Gemeinsames Riicknahmesystem Batterien, (GRS Batterien). This is a federation which now represents more than 430 battery producers and importers across Germany. They organise collection via trade and municipal collection centres as well as industry. They provide more than 130,000 return points for batteries to ensure that it is easy for the consumer to return used products. In addition they provide all of the collection containers and organise reverse logistics from the points of collection to the sorting facilities. The collection rate has grown from 5,700 tonnes in 1998, to in excess of 9,300 tonnes in 2000.
Competing against GRS Batterien in Germany is Vfw-REBAT, a profit orientated battery collection company. This company also offers a nationwide collection and recovery/disposal service for the german market. They occupy a certain market share, particularly for special use batteries such as those used for agricultural fencing and signal lamps. Robert Bosch GmbH also operates battery collection but only in the field of battery packs for electrical power tools. GRS Batterien remain the largest organisation with responsibility for more than 80% of the market.
- The Netherlands
Dutch legislation classifies a number of domestic products such as paints, medicines, pesticides and all types of batteries, as small chemical waste (KCA). Importers or manufacturers of these products are required to mark them with a special KCA symbol either on the packaging or on the product itself. The general public are informed that these products must not be disposed of with other household waste, but they are to be stored separately in a special KCA container, an ecobox. These wastes are collected separately on a regular basis by the municipality, and stored in one of more than 450 municipal depots. This is an example of a co-mingled collection system. The municipalities themselves are responsible for the adequate functioning and the costs of this part of the process.
The battery industry takes up responsibility from the municipal depots, and the cost for the remaining steps in the process. These include the shipment from the municipal depot to a central storage facility, as well as the sorting and recycling of the batteries. The dutch legislation has been in force since 1995, the year after the battery industry established Stichting Batterijn (Stibat), the dutch NCRA. This makes Stibat one of the longest established collection and recycling associations in Europe.
As in Germany, manufacturers or importers are not obliged to be part of a joint venture such as Stibat, for collection and processing; however a joint approach has considerable advantages over stand-alone solutions. Today Stibat has over 450 members.
Originally return of batteries via the KCA collection system was only approved on the basis that high collection rates could be achieved. Targets set by the government were 80% by the 1st January 1996 rising to 90% by the 1st January 1998. It soon became apparent that these rates were unachievable.
A number of factors can be identified which are responsible for this, particularly the fact that the general public either hoard batteries within the home or are ignorant of their responsibilities to return used batteries via the KCA system. As the aim of the dutch decree is to prevent used batteries from being discarded through the household waste stream or simply into the environment, Stibat proposed a revised collection rate that takes into account a hoarding factor. This method of calculating collection rate assumes that the batteries which are stored within the home have no negative environmental impact. As the occurrences of batteries being discarded uncontrolled into the environment is negligible, the success of any collection process can be determined by its ability to keep batteries out of the municipal household waste stream. Using this method the collection rate for batteries in the Netherlands in 1998 was found to be 75%. This calculation method has been accepted by the dutch government.
Stibat are still faced with achieving the exceptionally high collection target of 90% in 2003. Hence Stibat has now introduced additional collection schemes to improve the collection rate. These include reverse distribution as well as programmes with schools. Approximately 2,500 retail outlets are now participating in the take back scheme. Food chains are not included in this programme in order to avoid KCA waste being included in reverse logistics. Schools are offered an incentive programme whereby points are awarded per kg of batteries collected and these can be exchanged for equipment for the school. Over 2,000 schools participate in this scheme.
Belgium has an "ecotax" law which subjects all batteries to an environmental tax of BEF 20 (€ 0.5) plus VAT for each battery. This is regardless of the size or chemical system. However, exemptions from this ecotax are possible if one of the two following conditions is met.
Firstly the battery manufacturer or importer must distinctly mark the battery and submit to a deposit valued at € 0.25 per battery. The obligations of collection and recycling will then be met by the taxpayer.
Alternatively, a legally defined voluntary scheme for collection and recycling of batteries can be used.
A deposit scheme for the return of batteries has a number of drawbacks. Technically it would be unrealistic to expect manufacturers to mark products for a small market such as Belgium, when they are produced on a global scale. The scheme would be complex to administer, particularly with the risk of fraud resulting from batteries being returned which were purchased outside of Belgium.
Battery manufacturers and importers therefore elected to collect and recycle or treat all batteries under a voluntary agreement with the government and in 1995 established Bebat to manage this scheme. This scheme is funded through a collection and recycling fee, which is set and only adjustable by Royal Decree and is presently set at BEF5 per battery (€ 0.12). When a company joins Bebat, the Finance Ministry awards them temporary ecotax exception, which is conditional upon the collection objective being achieved for all Bebat members jointly within that year. Penalties are threatened for non-achievement.
The Bebat collection scheme relies heavily on the reverse distribution model, utilising over 13,000 retail outlets. An additional 5,000 collection points are available in schools, education centres and youth clubs and 600 through container waste parks, operated by municipalities. Further collection points are present in the industry or other bulk users such as hospitals or the military.
As with Stibat, a significant and growing proportion of the Bebat costs are being spent on public awareness and promotion. Once again, this is due to having to achieve, or strive towards, a very high collection target.
The legal obligation to separately collect all batteries for recycling came into effect from the beginning of 2001. Prior to this, only rechargeable batteries were required by law to be collected. As a result, two NCRA's were formed at different times by the battery industry. The first, Société de Collect et de Recyclage des Accumulateurs (SCRA), representing rechargeable manufacturers and OEM producers, and the second Fibat, representing the interests of the primary battery manufacturers. Both of these organisations are now working together as a joint organisation called Société de Collecte et de Recyclage des Equipments Electriques et Electroniques (SCRELEC) together with electronic equipment manufacturers.
The SCRELEC collection process is very similar to that operated by GRS Batterien in Germany. Collection boxes of various types are distributed to collection points. Currently two waste management companies have been contacted to collect the batteries from the various collection points including: stores, business or industrial sites and municipal waste facilities, and forward them to a sorting facility. This scheme is co-ordinated via a national call centre. SCRELEC has released an invitation to tender for the collection sorting and recycling of batteries in France.
Several large retail chains have also set up their own independent collection schemes in collaboration with french recycling companies to meet their obligations under french law.
Austrian law requires retailers and wholesalers to take back used batteries from consumers free of charge. Municipalities are also obliged to accept used batteries from private citizens. Battery manufacturers and importers have established an organisation called Umweltforum Batterien (UFB) to administer the scheme for collection. It can handle sorting and disposal or recycling of batteries.
National law on substances (Annex 4.10 dated 01.07.98) requires consumers to bring back used batteries or accumulators to point of sales or collection centres. Battery retailers are obliged to take back the types of batteries they sell. Municipalities too are participating voluntarily to establish separate battery collection points. Collected batteries are then transported to one of regional battery collection centres, which are operated by the battery recycler. A mandatory tax is paid by battery marketers to a private company, INOBAT, to finance the cost of collection, transportation, recycling and a public awareness campaign.
The environmental protection plans of the swedish government focus only on those batteries containing mercury, cadmium and lead. However, all batteries are collected in order to maximise the capture of these hazardous materials. The government imposes a levy on nickel cadmium batteries, lead batteries and mercury containing button cells. The money raised is used to fund collection and sorting, which is undertaken by the municipalities. Mercury, nickel cadmium and lead batteries are sent for recycling and all other batteries are landfilled. Significantly, the swedish government does not impose a collection target because it is believed not measurable. - Portugal
The separate collection of all batteries will commence in July 2001. Municipalities and retailers have the responsibility of collection from consumers, but producers and importers take responsibility for the batteries from designated depots. A mandatory collection target of 25%, based on annual sales by weight, has been set. The battery industry is setting up a collection and recycling company to manage its obligations under Portuguese law.
• Future Options for Battery Collection
A report commissioned by the UK Department of Trade and Industry, from the consultancy group Environmental Resources Management, ERM, entitled Analysis of the Environmental Impact and Financial Costs of a Possible New European Directive on Batteries3, published in November 2000, raises questions about the principle of the separate collection of waste streams. This report studied collection of consumer batteries by three schemes commonly used around Europe: kerbside collection, takeback via retail outlets and the consumer returning used batteries to a municipal waste collection facility. The report considered emissions due to transportation, fabrication of special collection containers and effects on the climate, soil and water. It concluded that, while recycling of batteries does produce a positive environmental impact, separate collection of batteries produces a negative environmental impact, which far outweighs the positive benefits of recycling. This gap widens as the collection target increases.
This report in itself is not conclusive. However it does stimulate debate on the separate collection of wastes in general. Further work is necessary in order to determine alternative solutions to reduce the differential between the negative impact of collection and the positive impact of recycling. One possible approach is to integrate the collection of primary batteries together with other suitable waste streams. Clearly such an approach will depend on the end use of the waste batteries, but the advantages in terms of minimising collection and transport impacts are obvious.
The report findings also question the benefits of imposing high collection targets. The issue of collection targets has concerned the battery industry for some time. Of primary concern is the measurability of a collection target expressed in percentage terms. It is unrealistic to use sales statistics for any one given year as the baseline for such a calculation. This is because battery life is dependent upon the appliance in which it is used. Most primary batteries for example, remain with the consumer for between two and three years. But it is not uncommon to find batteries returned in collection systems which are ten or more years old. Calculating the correct baseline is therefore very difficult and often questionable. The battery industry has therefore proposed collection targets based on a weight per capita, taking into account results achieved to date in countries with established collection processes, as well as the need to avoid unnecessary environmental burdens.
Battery Recycling • Dedicated/Unsorted batteries
A number of waste handling companies dedicated to recycling batteries have developed as a response to the increasing battery legislation around Europe. The collection schemes, operating throughout Europe at the time of writing, collect mixed and sometimes very old batteries. Recent sampling undertaken at the Dutch battery collection facility in Rotterdam have shown that in excess of 90% of the primary batteries collected contain no added mercury. Consequently, despite the fact that the majority of batteries collected are mercury free, the overall mixture of batteries still contains mercury. Until recently there has not been any quick and reliable method for distinguishing between the older, mercury containing batteries and the younger mercury free batteries. As a result, the dedicated battery recycling companies have tended to concentrate on processing mixed or partly sorted batteries, within mercury tolerant processes. This approach has a number of advantages and disadvantages.
The ability to process mixed or partially sorted batteries is attractive since the waste generator is required to undertake either none or only the minimum amount of preprocessing before sending the batteries for recycling. This reduces the up-front cost for the waste generator. But feeding unsorted batteries will introduce a number of undesirable elements into the process, not least of which is mercury. Mercury control and treatment is difficult and expensive. As all of the batteries are treated as if they were mercury containing, then an additional, unnecessary cost is added to the processing for the zero mercury added batteries. This cost is returned to the waste generator.
Dedicating processes for recycling is always likely to result in a high processing cost as the entire capital investment must be realised against the waste being recycled. With unsorted batteries, the composition of the feed to the process is relatively uncontrolled, consequently the process is likely to produce variable quality products, whose marketability and market value are limited. The alternative is to introduce further processing steps in order to improve the quality of the product pre-market, thereby adding further to the cost.
• Hydrometallurgical processes
Wet chemical, or hydrometallurgical processes for battery recycling differ fundamentally from pyrometallurgical approaches in that they aim to produce finished products with a high resale value rather than lower value material, which is further refined or used in a separate industry. This quest for greater added value is often borne out of necessity, to cover the high capital investment and operating costs.
Early hydrometallurgical battery recycling processes concentrated on attempting to recycle a mixture of all batteries, both primary and secondary, without any sorting of the different chemistries. This approach often requires an increased number of process steps in order to eliminate or reduce the considerable number of impurities which would otherwise significantly reduce the value of the products or even make them unsaleable. Furthermore, since the input stream is constantly changing, a high degree of analysis and control is necessary while processing. This all adds to the complexity and therefore the cost of hydrometallurgical recycling of batteries.
The technology being developed today accepts that pre-sorting can be beneficial to the hydrometallurgical recycling route. Zimaval, France, is a good example of selectively processing batteries by wet chemistry. The company specifically aims to recycle only three zinc bearing battery chemistries: alkaline, zinc carbon and zinc-air. Because the processing of these batteries also varies to a certain extent, they use sorting not only to remove other battery systems from the mix, but also to separate the three battery chemistries in order to batch process them. Zimaval have developed their own in-house sorting technology to do this.
Following sorting, the batteries are shredded. The zinc-air batteries, which are typically large industrial units, need to be cut and broken before processing. The alkaline and zinc carbon batteries are shredded in an automated unit. The former under sodium hydroxide and the latter under a water spray. The water wash is necessary to eliminate the chlorides within the zinc carbon cells before leaching. Plastics, paper and metals, both ferrous and non-ferrous are removed at this stage. The paper and plastics are segregated and sent off site for incineration with energy recovery, and the metals, once separated by eddy current techniques are sold.
The fines fraction, consisting mainly of zinc and manganese oxides and carbon, are leached in a sodium hydroxide bath. This selectively dissolves the zinc. Any amalgamated mercury present in the zinc precipitates out at this time and settles at the bottom of the reactor. This is periodically tapped off and sent for specialist treatment. After filtration, the zinc rich filtrate is allowed to cool naturally, then dendritic zinc is deposited by electrolysis. This is potentially a high value material used within the paint industry. The sodium hydroxide is recycled back into the alkaline leaching process.
The filter cake consists primarily of oxides and hydroxides of manganese and carbon compounds. A sulphuric acid plus hydrogen peroxide leach is used to dissolve all of the manganese components as sulphates. Metallic impurities and hydroxides are also dissolved. The sulphuric acid is provided from recycling lead acid batteries. Carbon and some of the remaining impurities from the manganese dioxide remain in suspension and are removed by filtration.
The filtrate contains zinc sulphate and manganese sulphate. The zinc sulphate precipitates out and is recovered. Sodium carbonate is then added and the manganese precipitates out as manganese carbonate, which is sold in the manganese industry
The zinc-air treatment is somewhat simpler because the absence of manganese dioxide means that the acid treatment is not necessary. After the batteries have been opened, they are immersed in sodium hydroxide within a trummel. The fines, containing zinc powder, zinc oxide, carbon and lime are suspended in solution and undergo the same zinc treatment as described above. After washing, the large fraction consisting of polypropylene pieces, steel and carbon are sorted and recycled within specialist industries.
The current capacity of the Zimaval facility is in the order of 4,000 tonnes per year.
Erachem in Belgium also adopt the approach of selective hydrometallurgical processing. Their target is even more specific in that they recycle only the manganese and zinc fraction from the primary batteries. Following a battery sorting operation, the batteries are shredded and milled to liberate the fines fraction or 'black mass' which contains the zinc and manganese in the form of a complex mixture of oxides. This mixture is subjected to a sulphuric acid leach, before a purification stage, then sold as manganese and zinc salts and oxides. One important difference of this process, compared to the Zimaval process, is the scale of the operation. Erachem, Europe are not dedicated battery recyclers, but are a chemical company who's primary interest is in the production of manganese salts for the battery, electronics and agrochemical industries. They also produce carbon black, used in batteries, tyres and plastics amongst other applications. The primary battery recycling is therefore undertaken by campaigns within the existing chemicals plant. Consequently it is difficult to calculate the exact capacity of the operation, but it is safe to say that this can be measured in tens of thousands of tonnes.
The metal fractions are not lost with this process, but the responsibility for their recovery rests with the battery pre-processor. Today Erachem have partnerships with two pre-processors, Revatech in Belgium, who employ a dry separation methodology, and Duclos Environnement, France, who wet shred the batteries.
• Pyrometallurgical processes
One of the first battery recycling plants available in Europe was the Batrec recycling plant in Switzerland. This plant operates a pyrometallurgical process developed by Sumitomo Industries in Japan. The process consists basically of three stages. The first is a pyrolysis of the organic substances, water and the mercury in the shaft furnace at temperatures of between 400 to 750 degrees centigrade. It takes up to four hours for the organics within the batteries to be evaporated and the mercury to be liberated. The organics are destroyed by burning in a post-combustion chamber. The exhaust gases are rapidly cooled down to prevent build-up of dioxins and washed in several stages before being released to the atmosphere. The mercury is further distilled and sold.
Pyrolysis is followed by the smelting of the metallic factions within an induction furnace. The batteries are automatically fed into the introduction furnace, reductant and fluxes are added and the iron and manganese are melted to produce ferromanganese and the zinc evaporates. The liberated zinc then passes through a splash condenser where it is returned as zinc metal. The carbon monoxide produced as a by-product of the zinc oxide reduction is washed and fed back into the pyrolysis as fuel (energy recovery).
The Batrec plant was built as a dedicated battery recycling facility, but with a flexibility towards a wide range of other mercury containing wastes.
However, as with most pyrometallurgical battery recycling processes, the high cost of mercury control has ensured that the processing cost has also remained high. Consequently, the use of the facility by organisations outside of Switzerland with the responsibility to collect batteries, is limited to mercury containing batteries or unsortable battery wastes. As a consequence all of the dedicated pyrometallurgical battery recyclers now take additional mercury containing wastes to reach their nominal capacity and remain viable.
Batrec remain the most expensive primary battery recycling facility in Europe today. Operating costs for this process are in excess of 3,000 swiss francs per tonne when the process is being used at the capacity of less than 5,000 tonnes per year. However Batrec profits from a swiss Directive that forbids the exportation of wasteful recycling out of the country when a facility exists within Switzerland. Batrec, as the sole battery recycling facility within Switzerland, remain in a monopoly position.
It is obvious that only those battery recycling facilities which offer economical processing will remain viable in the long-term within a competitive market. Any primary battery recycling facility which concentrates on mercury removal at high cost has a very limited lifespan.
• Waste Stream Analysis
As previously discussed, the major battery manufacturers in Europe, Japan and the United States had all successfully eliminated mercury from primary batteries by 1993. Consequently the mercury burden on the environment from waste primary batteries has been significantly reduced and continues to reduce year on year. The question remained, "at what point in the future would all batteries which were sold before 1993 have been disposed of by the consumer?" If this date can be ascertained, then all primary recycling operations after that date need only concentrate on resource conservation and not toxic elimination.
The battery industry developed a statistical method for determining the concentration of mercury in the waste stream at any point in time, and used this to predict the future date by which all of the mercury within primary batteries will have passed through the waste stream. This method, which uses date code analysis was developed over a period of many years through stockpile analyses in Germany, Sweden, Belgium and The Netherlands. It is employed annually in Europe to forecast the decline of residual mercury in the collected batteries within The Netherlands, which is considered typical of other european battery markets.
Manufacturers generally either stamp date codes on the base or side of the battery, or include a freshness code on the battery label. The age of each battery and hence the mercury content can be determined by recording the manufacturers code and converting this back to the year of manufacture. Some batteries can be assigned to manufacturing dates one year earlier than their actual year of manufacture as a result of using freshness codes, simply because the manufacturer will not replace his stocks of battery labels on January 1st each year.
The mercury content of the batteries for each year of manufacture can be calculated from historical manufacturing information held within the manufacturers records. These in turn can be used to determine the mercury contents of the alkaline and zinc carbon streams within the sample.
Some assumptions are made. Firstly, when a manufacturer changed the mercury content of a battery, all batteries manufactured in that year were taken as having the higher mercury content. Secondly, batteries which were corroded beyond the point of date code recognition were taken as having the highest mercury concentration for that battery type. Finally, all batteries manufactured before mercury concentration data was available were taken as having the same concentration as the year in which the first data became available. The first two assumptions are likely to bias the mercury content higher rather than lower than the actual level. The third assumption is unlikely to cause any major fluctuations to the overall mercury content, since these batteries were manufactured before mercury reduction programs were introduced.
In general this method of analysis will give a "worst case" mercury concentration.
Sampling is undertaken at the Sortbat sorting facility in Rotterdam, The Netherlands. For the year 2000 analysis, every 200th alkaline and zinc carbon battery was automatically sampled over a period of 4 weeks. The resulting sample was hand sorted and the Philips, Varta and Duracell batteries segregated for date code analysis. These manufacturers are used as a surrogate for all of the european battery manufacturers. Previous analyses have shown that the mercury reduction programmes between the major manufacturers followed similar lines and no significant error is introduced by doing so.
Most asian manufactured batteries arrive into the european market already installed in electrical equipment. These are mainly japanese produced alkaline or zinc carbon's, which have similar mercury content to european batteries, or are low quality zinc carbon batteries, imported in cheap toys. The low quality zinc carbon batteries were found by chemical analysis, to be within only a few parts per million of mercury different from those manufactured in Europe. Neither of these battery types are a significant contributor to the overall european market.
The mercury content of the primary battery waste stream has been analysed in this way since 1995. Based on early data, a forecast has been made of the future anticipated mercury concentration of the stockpile and consequently the point in time at which the stockpile will become "mercury free". The forecast was made by taking a histogram of the age distribution of the batteries within the sample and calculating the overall mercury content. The mercury concentration for subsequent years is predicted by shifting the distribution forward by one year and re-calculating the overall mercury concentration. This process is repeated until the oldest cells found are manufactured in mercury free years. Using this method, the mercury level of primary batteries falls to background levels by 2004. This projection is given in Figure 1.
The graph shows the average mercury concentration, (the solid line) bordered by an upper and lower anticipated limit (the two dotted lines). The upper and lower limit curves have been generated by assuming that highest mercury or the lowest mercury containing batteries for each particular year are found. Consequently we would expect the mercury concentration for primary batteries to fall between these two limits. The 1996 through 2000 analyses are superimposed on the curve. These indeed show that the annual measurements fall within the expected range (note the 1999 analysis was
Average Hg Content (%}
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