by Tony Breton
Since 1999, the principal central policy driver for the biological treatment of biodegradable wastes has been the EU Directive on the Landfill of Waste (99/31/EC). The directive places strict limits on the amount of biodegradable municipal waste (biowaste) that can be disposed of to landfill, as well as introducing a requirement for pre-treatment of all wastes prior to landfill.
These increasingly restrictive targets have required Member States to reduce the amount of biowaste going to landfill (based on 1995 levels) by 35% in 2006, 50% in 2009 and 65% in 2016. Due to their historic reliance (more than 80%) on landfill for waste disposal, the UK, Greece and EU-10 (i.e. the 10 countries that joined in 2004) have received a four-year derogation for each of these targets.
The Landfill Directive itself does not stipulate how these targets should be reached and for many years there have been calls for a separate directive on biowaste. Protagonists of the Biowaste Directive have argued that without a legal requirement for separate collection, and in the absence of any binding quality criteria for final products (composts and digestates), a huge opportunity to improve the quality of soil across the EU, whilst simultaneously addressing the landfill issue, is being lost.
The importance of soil as a resource was first recognized in 1972 with the Council of Europe’s European Soil Charter, since then Member States have, to a greater or lesser extent, adopted a variety of local strategies and policies to ensure the protection of soil.
Following almost a decade of discussion, in April 2002 the European Commission adopted a communication entitled ‘Towards a Thematic Strategy for Soil Protection’ which was followed up in 2006 when the Commission proposed a Soil Framework Directive and also a non-legally binding Thematic Strategy. In 2007, the Thematic Strategy was agreed but due to disagreements from some Member States, the Framework Directive (which included recommendations for specific tools on biowaste) was not finalized and the future of the directive remains unclear.
Whilst the Soil Framework Directive has stalled, revisions to the Waste Framework Directive (WFD) have been completed. The WFD has some significant changes from its predecessor, including a specific Article on Biowaste. The current Article 22 states:1
‘Member States shall take measures, as appropriate, and in accordance with Articles 4 [the waste hierarchy] and 13 [protection of the environment], to encourage:
- (a) the separate collection of biowaste with a view to the composting and digestion of biowaste
- (b) the treatment of biowaste in a way that fulfils a high level of environmental protection
- (c) the use of environmentally safe materials produced from biowaste.
- (b) the treatment of biowaste in a way that fulfils a high level of environmental protection
The Commission shall carry out an assessment on the management of biowaste with a view to submitting a proposal if appropriate. The assessment shall examine the opportunity to set minimum requirements for biowaste management and quality criteria for compost and digestate from biowaste, to guarantee a high level of protection for human health and the environment.’
 |
Further to the specific reference on biowaste, the WFD also contains a requirement for 50% recycling of municipal waste by 2020, however it is not clear whether or not centrally composted garden waste will count towards the 50% target. It is clear that the combination of the revised WFD and ongoing requirements of the Landfill Directive will help drive the separate collection of biodegradable wastes and the production of environmentally safe products suitable for a range of purposes including the improvement of soils.
Across the EU, a wide range of different local policies and fiscal tools have been adopted to decrease reliance on landfill. Fiscal tools such as landfill taxes, charging for waste collection and other tax mechanisms (e.g. packaging tax or specific taxes, see LAS inset box) are commonplace. Local tools include particular policies which require the separate collection of materials and the banning of biodegradable wastes from landfill. All of the countries which have the highest diversion rates have implemented a range of such measures, whereas those with lowest diversion utilize these less. Whilst countries such as Austria (see inset box p. 57), Germany, Italy, France, Denmark and Sweden have high diversion rates, in some countries (such as France and Denmark) the preferred treatment route for biowaste is not biologically based, but is incineration, with or without energy recovery. However, given the need for sustainable options for renewable energy a number of countries, e.g. Sweden and the UK, have introduced fiscal tools which enable the development of anaerobic digestion – thus encouraging the production of both renewable energy and high quality compost-like materials.
Biowaste developments in the UK
The past 15 years has seen significant developments in the UK biowaste industry and it is now estimated to have an annual turnover of around £100 million.2 Driven initially by recycling and composting targets, and more recently by the Landfill Allowance Schemes and escalating landfill tax, municipalities have placed increasing emphasis on improved services for the collection of biowaste. Given that all the targets/allocations are based on weight, the majority of these schemes have specifically targeted garden waste.
The growth and increasing popularity of centralized composting is reflected in Figure 1 and it is estimated that in 2006/2007, approximately three million tonnes of municipal waste and 600,000 tonnes of non-municipal waste was separately collected for biological treatment (composting/anaerobic digestion), with the majority of the final compost products being utilized in agriculture.
 Figure 1. Growth of the UK composting industry showing proportions of municipal solid waste3 |
In the UK the most common kerbside collection receptacle for garden waste is wheeled bins, but increasingly municipalities are offering compostable (certified to EU Standard EN13432) and reusable bags as alternatives. Whilst the prevalence of kerbside collection schemes is high, the majority only have limited coverage and often this is due to issues with access to gardens or storage space. Subsequently when looking to widen the availability of these schemes, the use of bags is an increasingly common option. In addition, by offering a choice of receptacle it allows the public to decide how they want to collect their waste, which can encourage participation, but also in areas where garden waste is a charged collection, the option of paid bags can encourage the public to home compost more than if they have a paid bin collection.4
 Slave bin food waste collection in Italy – used as a base model for UK trials |
It is worth noting that experience in Austria, Belgium, Germany, Switzerland and the UK has shown free garden waste collection in large containers will not only increase recycling rates but also lead to significant increases in overall municipal solid waste (MSW). The early expansion of such wheeled-bin collections of garden waste has also shaped the initial collection systems for food waste. These schemes allow the addition of food waste to garden waste and such a service is now offered by 53 municipalities across the UK. Whilst this seems a good option, the evidence shows that it is not the most environmentally or economically efficient system. Without restrictions on residual waste collection frequency or capacity, there is little incentive for householders to put putrescible food into the same container as the garden waste where it may stand for up to two weeks leading to potential odour issues. The food content of such mixed collections is in the region of <0.5 kg per household per week5 which represents an extremely low level of capture and thus a high level of biowaste remains in the residual waste.
The development of mixed food and garden waste collections has been accompanied by a rapid expansion of enclosed composting facilities. Following the introduction of the Animal By-product Regulations 2003 all composting facilities treating Category 3 animal by-products or catering waste must be fully enclosed and comply with the strict process requirements. Such facilities have a higher gate fee than traditional open air windrow sites (median £40, compared to £22.50 per tonne).6 Consequently, disproportionately high quantities of garden waste are processed at a significantly higher cost.
Over the past few years there has been a move towards a weekly separate collection of food and now over 50 municipalities are either trialling or have rolled out such systems. This follows the system which has successfully operated in northern Italy for a number of years and was used as the basis for the Waste and Resources Action Programme (WRAP) food waste trials.7 Householders are typically provided with small kitchen caddies (5 to 10 litres) and outdoor caddies (25 to 20 litres) – generally with certified compostable liners for the small caddy. All food waste is placed into the kitchen caddy, and once full the bag is tied, removed and placed in the outdoor container.
Typically, weekly separate collections where householders are provided with caddies and liners will, in comparison to mixed food and garden waste collections, achieve much greater levels of food waste recovery: 2–3 kg per week per household served, levels for schemes without liners are generally 50% lower. As with the mixed collections, the collection frequency of residual waste is an important factor in determining the success of separate collection schemes in terms of recovery (see Figure 2) and crucially, the economics of whole collection and treatment system.
 Figure 2: Average food waste yield per participating household per week for WRAP supported trials8 |
The efficacy of the two caddy system is also seen in the street-side collection where is it estimated that wheeled bins take on average three minutes to collect, empty and return to the household, compared with less than one minute for caddies with liners. The dense material which does not require compaction is then collected in bulking vehicles – in Northern Italy these vehicles are typically operated by a single driver/loader which reduces costs and does not affect collection performance.
 Final product from a joint dry anaerobic digestion/ composting plant |
Collecting food waste separately can have additional benefits for the processor as it provides cleaner feedstocks and allows composters, who also accept separately collected garden wastes, to mix the separate streams to attain the optimal carbon to nitrogen ratio. Due to its highly putrescible nature the material is extremely suited to many anaerobic digestion systems, particularly the dry systems co-sited with composting plants which are becoming state of the art in Europe.9 To date, anaerobic digestion has not been widely implemented in the UK, with only a few plants accepting municipally sourced biowaste. This is likely to change in the coming years following the publication of Waste Strategy 2007 (England), and the establishment of development funding schemes across the UK and favourable fiscal incentives for renewable energy from anaerobic digestion.
Future outlook for the UK
Over the past 15 years the UK biowaste industry has undergone significant change and growth. Unlike many European countries, regulatory pressure and incentives have been relatively slow to be enacted and are only now forcing the industry to diversify into the increasingly advanced systems which have been common place in Europe for the past decades. The lack of long-term planning may well result in the UK missing its Landfill Directive obligations, and two recent reports from Defra and the Audit Commission both suggest that without further urgent action the 2013 and 2020 targets will be missed. However, the current drive for separate collections of biowaste, combined with at least two million tonnes of planned additional processing capacity in the next five years, suggest the UK biowaste industry is now thriving and will play an increasingly pivotal role in the nation’s drive towards sustainable waste management systems.
Tony Breton is a UK-based consultant with Novamont SpA, Italy
e-mail: tony.breton@novamont.com
References
1. http://www.europarl.europa.eu/sides/getDoc.do?pubRef=-//EP TEXT+TA+P6-TA-2008-0282+0+DOC+XML+V0//EN
2. Association for Organics Recycling Oct (2008), Market survey of the UK composting industry, 2006/07
3. See 2
4. Hogg D., Gibbs A., Favoino E. & M. Ricci (2007), Managing Biowastes from Households in the UK: Applying Life-cycle Thinking in the Framework of Cost-benefit Analysis. A Final Report for WRAP. www.wrap.org.uk/biowaste
5. Crichton L. (2008), Food Waste Collection Trials – Update and Lessons learnt so far. http://www.resourcesnotwaste.org/CONFERENCES/FW(London)-papers/04.WRAP%20TRIALS%20Linda%20Crichton.pdf
6. WRAP (2008), Comparing the Cost of Alternative Waste Treatment Options
8. Bridgwater E & J Parfitt (2008), Evaluation of the WRAP Separate Food Waste Collection Trials
9. De Baere L & B Mattheews (2008), State of the Art 2008: Anaerobic Digestion of Solid Waste. Waste Management World
UK Landfill Allowance Schemes
Tying in with the targets of the Landfill Directive, the Landfill Allowance Schemes will see progressively tighter restrictions on the amount of biodegradable municipal waste (catering and garden waste as well as paper) that can landfilled by the different countries of the UK. For the UK, the maximum allocations for the years 2010, 2013 and 2020 are 13.7 million, 9.13 million and 6.39 million tonnes respectively.
Each waste disposal authority (WDA) has received its own allocations in order that the UK meets its permitted allocation for each Landfill Directive target year. Local authorities are being given flexibility in the way they meet these progressively tighter restrictions through the Landfill Allowance Scheme – each country of the UK has a slightly different scheme. WDAs have all been allocated annual landfill allowances. Authorities with low landfill rates can sell or ‘bank’ surplus allowances while those that exceed their limit will be fined up to £150 per tonne. There is, however, no trading between authorities in Wales.
Decentralized biowaste management in Austria
Since 1992 and the announcement of the first Austrian Biowaste Ordinance, Austria has been a leader in the delivery of successful local biowaste management schemes. Coming into law in 1995, the Ordinance prioritized home composting, required the complimentary separate collection of biowaste, and favoured decentralized, local agricultural composting. In 2002 a further Compost Ordinance came into force which laid down the rules for composting processes and gave definitions of when compost became a product.
Sustainable energy has also been important in Austria for decades – with ecology orientated taxes on energy and more recently the introduction of the Eco-power Act which further obligates the use and development of renewable energy sources including anaerobic digestion.
The Ordinances, together with early implementation of landfill taxes and packaging collection schemes and (more recently) a ban on biowaste to landfill, has meant that for many years Austria has had the highest rate of composting in Europe.
