February 15, 2004 | General

Composting Increases Steadily At British Sites

Tony Breton
BioCycle February 2004, Vol. 45, No. 2, p. 60
During the 1990s, the composting industry in the United Kingdom (UK) grew considerably, and this growth has continued into the new millennium. Much of it has been due to the expansion of municipal solid waste (MSW) composting, in particular green waste composting. However, the expansion of the UK composting industry seems to be inextricably linked to increased regulation and the need to adopt more stringent operational practices requiring an increase in the diversity of composting processes and wastes utilized.
The European Union Directive on the Landfill of Waste (99/31/EC), which came into force in 1999 has, to date, been the principal driver behind the growth in composting in the UK. In addition to stipulating the way in which landfill sites should be operated, it places strict limits on the amount of biodegradable municipal waste that can be disposed in landfills, and introduces a requirement for pretreatment of all biodegradable wastes prior to landfill. The Directive is therefore likely to have a profound effect on the way in which wastes will be collected and processed, and will inevitably stimulate the development of the composting sector.
During the early part of this decade, the European Commission published a number of Working Documents on treatment of biowaste and sewage sludge as well as a communication titled “Towards a Thematic Strategy on Soil Protection.” It has now been decided to make the development of the proposals on biowaste and the revision of the Sewage Sludge Directive an integral part of the multi-stakeholder process accompanying the development of the Soil Thematic Strategy expected to be adopted in September 2004. To this extent, a further Working Document was published in December 2003, in which the main proposals are:
o The adoption of minimum process requirements (residence time, temperature, environmental conditions, etc.) for anaerobic digestion, composting and mechanical/biological treatment (MBT)
o Separate collections of the biowaste fraction of MSW
o Compost should be considered a product only if it has been made from separately collected biowaste
o A classification for composts, distinguishing between grades of “compost,” and “stabilized biowaste”-MBT “compost” along with restrictions on their respective application rates and usage
o Harmonization of sampling, testing and labeling criteria for composts
The Waste and Emissions Trading (WET) Act 2003 is a new measure that the UK government has introduced to help meet demands of the European Landfill Directive. Tying in with the targets of the Landfill Directive, the WET Act will see progressively tighter restrictions on the amount of biodegradable municipal waste (catering and garden waste as well as paper) that local waste disposal authorities can landfill.
Local authorities are being given flexibility in the way they meet these progressively tighter restrictions through the key measure of the WET Act, the Landfill Allowances Trading Scheme (LATS). Through the LATS, waste disposal authorities are allocated annual landfill allowances. Authorities can then either stay within their landfill limits, or trade these allowances. Authorities with low landfill rates will be able to sell surplus allowances to high landfilling authorities.
EC Regulation 1774/2002 – Laying Down the Health Rules Concerning Animal By-Products Not Intended for Human Consumption – came into force across the EU on May 1, 2003. During the development of the regulation, concern by some Member States about the potential spread of animal diseases, such as Foot and Mouth Disease, through composting led to the inclusion of catering wastes (“all food including used cooking oil originating in restaurants, catering facilities and kitchens, including central kitchens and household kitchens” (EC 808/2003)) within the scope of the Regulation.
In the UK, EC 1774/2002 has been adopted through the Animal By-Products Regulations 2003, which supercede previous legislation in a manner which will allow the composting of catering wastes under certain national conditions ).
There are a number of other conditions regarding the site and operational procedures which are required before approval (from the State Veterinary Service) for the plant and process to be obtained. These include demonstrating clean and unclean areas, temperature monitoring, and recording and record keeping. A grazing ban will also be imposed if compost produced from catering waste is applied to grazing land. The ban will last for two weeks after application or eight weeks after application in the case of pigs being present on the land. The regulations do not apply to home composting (unless livestock is present on-site) or to the composting of source separated green waste. Schools, hospitals and prisons are exempt if the final material is to be used on-site.
The provisions of the regulation will have significant impacts on the UK composting industry. Given the high proportion of catering wastes that exist within the municipal waste stream and the legislative requirement for such wastes to be diverted from landfill, large-scale (in-vessel) composting and digestion facilities for treating catering wastes will be required. At press time, only seven facilities had been granted approval from the State Veterinary Service to treat catering wastes and/or Category 3 animal by-products. These include a housed- windrow system (inside a building), a vertical composting unit (VCU), two biogas plants, two MBT plants and an aerobic digestion plant.
Composting facilities in the UK operate on a number of different levels, from very small-scale sites producing less than 50 metric tons of compost per annum to those that process over 50,000 metric tons of waste per annum. The Composting Association’s annual surveys (State of Composting in the UK) have suggested that composting has developed considerably over the past few years. In 2001, 218 composting facilities were operating in the UK processing over 1.6 million metric tons. The facilities comprised 132 centralized (licensed sites processing >5,000 metric tons per annum), 78 on-farm and eight “other” sites. The majority (80 percent) of the centralized sites were operated by either dedicated compost producers or waste management companies with only 10 percent being operated by local authorities. The previous two years have seen particular growth in the acquisition of new sites by waste management companies and new players entering the market.
The State of Composting in the UK (2001-2) covered a period which coincided with the implementation of the Animal By-Products (Amendment) Order (2001). This piece of legislation (now superceded by the Animal By-Products Regulation 2003) effectively prevented the composting of food wastes under most circumstances. Consequently the amount of food wastes composted during this period was significantly lower than green wastes, despite estimates suggesting that it comprises around 17 percent (by mass) of the UK’s municipal waste stream.
The amount of material composted in the UK between 1999 and 2000/1 (Figure 2) increased by 100 percent; the majority of waste composted in 2001 was sourced from households, representing 1.2 million of the total 1.66 million metric tons. Green waste collected from civic amenity sites accounted for the 1.03 million metric tons, approximately 62 percent of the total composted in the UK, with the remainder predominantly collected curbside.
While the majority (79 percent of centralized composting facilities) operate open-air turned windrows systems, The State of Composting in the UK 2001/2 indicated that in recent years there has been an increase in the use of in-vessel technologies. Further significant increases in the number of in-vessel composting and anaerobic digestion systems, coupled with more local authorities providing curbside organics collection schemes, will need to be realized in the future in order to treat municipal food wastes.
Another trend highlighted by the most recent survey is a shift away from landfill diversification towards dedicated composting facilities (see Figure 3). Of the 132 centralized sites, only 12 percent were located on a farm and 35 percent were located on a landfill site, while 34 percent were at dedicated composting facilities. This is in marked contrast to 1999 when 50 percent of the UK’s composting took place on landfill sites.
Although there were a similar number of “dedicated composting facilities” and landfill-based composting facilities in 2001, a far greater percentage of compost was processed at dedicated composting facilities. It was also notable that Scotland and Wales relied more heavily on on-farm composting operations than England. This could reflect their rural nature, where a series of decentralized on-farm sites may better serve dispersed communities, reducing waste transportation.
Overall, England composted far more than any of the devolved nations, approximately 1.5 million metric tons, compared to Northern Ireland, Scotland and Wales that each composted less than 60,000 metric tons. However, further analysis revealed the amount collected per household was similar in England (72 kg/household/annum) and Northern Ireland (73 kg/household/annum), both of which collected more per household than either Wales (31 kg/household/annum) or Scotland (25 kg/household/annum).
The community composting sector represented a very small fraction (less than 0.2 percent) of the total amount of organic waste composted. The majority of schemes were very small, used simple mechanical or manual composting methods and operated under a license exemption. In view of the projected millions of metric tons of organic wastes that will need to be composted to meet the Article 5 targets set in the Landfill Directive, community composting seems unlikely to play a significant role in their attainment. However, as organic waste curbside collection schemes will need to be increased, the educational value of community-run schemes seems likely to become increasingly important in educating householders about composting.
Market development has a key role to play in the long-term future of the composting industry. The survey recorded approximately one million metric tons of composted products produced in the UK. Over one-third was utilized in outlets with a high pecuniary value including horticulture, landscaping and domestic gardening. One-third was used as landfill restoration or daily cover and the remainder was used in agriculture. Overall, the majority (68 percent) was used as a soil improver, which can be divided into 82 percent soil conditioner and 18 percent mulch; other significant product categories identified included growing media, turf dressings and topsoils.
If the UK composting industry is to continue to expand, further development of income-generating markets is essential. These markets demand composted products which are consistently safe, reliable and high-performing such as those which comply with the BSI PAS 100 specification. BSI PAS 100 for Composted Materials has been adopted by the Composting Association as the minimum specification that composted materials must meet in order to carry the Association’s certification mark. Over 50 percent of the UK’s high quality compost is now being assessed for certification from the Composting Association, with the number of compost producers joining the scheme more than trebling since April 2002. Together, the 28 compost producers currently on the scheme have gained or applied for certification of 35 composting processes and 53 composts (~500,000 metric tons).
The expansion of the UK composting industry seems to be inextricably linked to increased regulation and the need to adopt more stringent operational practices. More stringent environmental and health protection measures demanded by the UK’s waste regulators will inevitably result in economies of scale being realized. The recently implemented Animal By-Products Regulations (2003) permits the composting and digestion of catering (food) wastes and certain low risk animal by-products, but specifies that stringent sanitation and biosecurity measures are set in place. It is therefore probable that larger, technology-dependent, in-vessel facilities will need to be established to compost food wastes, while green wastes may continue to be composted at either centralized or smaller-scale on-farm sites.
In order to comply with the requirements of the Landfill Directive and assuming a growth rate of three percent the UK will need to divert six million metric tons of biodegradable waste by 2010. By 2020, that figure will increase to 17 million tons of biodegradable waste.
Tony Breton was Communications Manager of The British Composting Association. The State of Composting in the UK 2001/2 is free to download from the Composting Association’s website The State of Composting in the UK 2001/2 was funded by the Environment Agency and the Waste and Resources Action Programme.

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