BioCycle March 2011, Vol. 52, No. 3, p. 32
Composting and anaerobic digestion are firmly linked as tools to comply with the EU’s landfill directive, greenhouse gas reduction and renewable energy targets.
Nora Goldstein

LAST month, I had the opportunity to attend AD Europe 2011: The Future of Anaerobic Digestion in Europe, a two-day conference in Dublin, Ireland organized by the European Compost Network (ECN) and Cré, the Composting & Anaerobic Digestion Association of Ireland, and cosponsored by the European Biogas Association. Presentations provided excellent insights into trends across a broad spectrum of organics recycling policies, projects and research.
Perhaps one of the most significant takeaways from the two days of sessions is the increasing integration of composting and anaerobic digestion on the same footprint. “We are seeing a revamping of existing biowaste composting plants built in the 1990s to extend their treatment capacity by adding anaerobic digesters,” said Bruno Mattheeuws of Organic Waste Systems in Belgium, who tracks AD developments in Europe (see “Anaerobic Digestion of MSW In Europe,” February 2010).
Jan Liebetrau of the German Biomass Research Centre noted that about 8.6 million metric tons/year (tpy) of source separated biowaste are collected in Germany. Roughly 90 percent is composted, with the remainder – about 900,000 metric tons – anaerobically digested. “The addition of a digestion plant into an existing composting infrastructure and the utilization of biogas is expected to increase the greenhouse gas reduction potential of the treatment of biowastes,” said Liebetrau. “For 200 to 250 of the existing composting plants in Germany, the addition of an anaerobic step might be possible.”
In the Netherlands and Italy, biowaste composting facilities are in the process of adding anaerobic digestion systems as well. John van Haeff with Attero, a Dutch waste management company, noted that “all existing composting plants in the Netherlands are preparing plans for an anaerobic digester for processing of vegetable, garden and fruit wastes (VGF).” He provided examples of several facilities combining composting and AD, including Wilp – dry mesophilic digestion/aerated static pile composting, processing 70,000 tpy – and Henelo, using dry thermophilic digestion with tunnel composting, processing 50,000 tpy. In Italy, said Alberto Confalonieri of Scuola Agraria del Parco di Monza, 22 composting plants are integrating AD.
The timing of AD Europe 2011, about six weeks before the BioCycle Global 2011 Conference, made it possible to include this “snapshot in time” of organics recycling trends in the European Union in the Conference Preview report. A number of presenters at BioCycle Global are involved with the AD and composting facilities/technologies discussed at AD Europe 2011. The following highlights information from various presentations in Dublin.

ORGANICS MANAGEMENT POLICIES
The European Compost Network estimates that 115 million metric tons of organic waste are generated annually in the European Union. Roughly one-quarter is processed via composting and anaerobic digestion, with Germany leading the way, followed by Italy, the Netherlands, the United Kingdom and Austria. The European Union’s Directive 31, adopted in 1999, mandates the reduction of biodegradable municipal waste disposed in landfills. The first reduction target was 25 percent by 2010, then 50 percent by 2013 and 65 percent by 2020.
Bartosz Zambrzycki with the European Commission’s (EC) Environment Unit reviewed the EU’s biowaste policies, its impacts on anaerobic digestion and how far along member countries are in meeting the Landfill Directives reduction targets. The majority of EU countries have met the initial 25 percent target, but only a handful are close to the 50 percent reduction to be met by 2013. Several years ago, a Waste Framework Directive called upon the Commission to assess biowaste management in the EU and propose, if appropriate, measures to improve it.
The EC’s Biowaste Communication, issued in May 2010, stated that additional support for separate collection and biological treatment (e.g. targets) is justified on economic and environmental grounds, but that no additional legislation to accelerate biowaste recycling is needed. (In contrast, noted ECN, the Environment Committee in the European Parliament voted for specific legislation on biowaste in July 2010, including quality assurance. The Committee views the rules on management of biowaste as fragmented, with current legislative instruments insufficient to achieve the significant benefits derived from biowaste recycling, including CO2 reduction, soil improvement and bioenergy potential.)
The EC suggests that current legislation, especially the landfill and waste framework directives, be better enforced. The Waste Framework Directive includes a definition of “end-of-waste” criteria for composts/digestates to meet the legal status of a product. Zambrzycki noted anaerobic digestion can be counted as recycling (and thus used to meet the EU recycling targets) only if the digestate is used on land. He also mentioned that about one-third of the 2020 EU target to use renewable energy in transport could be met by using biogas produced from biowaste as a vehicle fuel.

BIOGAS INCENTIVES, MARKETS
While the EU’s Landfill Directive has clearly accelerated organics recycling, there is no question that favorable feed-in tariffs (FIT) for electricity have fueled adoption of anaerobic digestion to process municipal, industrial and agricultural residuals. “Every time a country improves its feed-in tariffs for digester biogas, growth occurs,” stated Arthur Wellinger, president of the European Biogas Association, founded in 2009. “There is a direct relationship.” A number of presentations discussed FIT, the role they have played in creating anaerobic digestion infrastructure in the EU and how long the high tariffs will last, as well as some of the downsides. An upcoming article in BioCycle Global will focus specifically on those trends and lessons learned.
One country poised for rapid growth due to high FIT is the Czech Republic, noted Wellinger. In 2008, 2009 and 2010, 40 plants a year have been built in the agricultural sector. “The FIT is 18 cent/kWh,” he said. He showed a graph from the Czech Biogas Association estimating that by 2020, the country will have close to 800 biogas plants producing about 500 MW/year of electricity.
Upgrading biogas for natural gas pipeline injection and vehicle fuel was discussed in a number of presentations. In Sweden, there is a very small natural gas grid (and no FIT for electricity), so more attention has been paid to use of biogas as a vehicle fuel. Michelle Eckman of the Swedish Gas Association (SGA) explained that Sweden is the only country with a biogas standard for vehicle fuel. By the end of 2010, SGA had identified 122 public gas filling stations selling biogas-derived fuel and 47 nonpublic stations for fleets, buses and heavy-duty vehicles.

DIGESTATE UTILIZATION
The ECN held the first meeting of its Work Group on Anaerobic Digestion on the first day of the conference. Earlier in the day, Angelika Blom of Avfall Sverig and Henrik Lystad of Avfall Norge – chairs of the AD Work Group – provided a review of digestate quality requirements and certification schemes in Europe. Belgium, Germany, Sweden and the United Kingdom have quality assurance standards on the output (liquid and solid digestate) of anaerobic digestion plants. Germany, for example, has separate standards for digestate from biowaste versus energy crops.
The ECN established a Quality Assurance Standard for Compost, and is discussing how to expand it to encompass digestate. An upcoming article will explore existing quality standards and report on current research regarding digestate utilization, including crop trials and nutrient analyses.

For more information on the presentations at AD Europe 2011, contact the European Compost Network, www.compostnetwork.info, and Crè, www.cre.ie.