European countries are revitalizing their approach to treating organic wastes. For many dec-ades, composting processes and quality control procedures failed to keep pace with the changing composition of the European waste stream, according to the Organic Recla-mation & Composting Association (ORCA), Brussels. As a result, compost quality deteriorated, composting systems collapsed and markets virtually disappeared.
In the meantime, the waste management hierarchy of reduction, recycling, incineration and landfilling has been adopted throughout Europe. Governments are setting targets of up to 50 percent recovery by 2000 to cope with rising landfill costs and a scarcity of acceptable sites. In the past, composting has been an "underutilized element" of the hierarchy, according to ORCA. Now, biological treatment is becoming a key player in meeting national recovery goals, especially since the organic fraction of the household waste stream can be as high as 50 percent or more in some countries.
As a result, quality standards and source separation will play a major role as biological treatment technologies evolve. "Composting sorted mu-nicipal solid waste is definitely 'out,'" according to Bert Lemmes, managing director of ORCA. "Only source-separated waste will be able to fulfill the imposed quality criteria."
Indeed, overcoming the bad image that compost from waste had in past decades is a challenge; setting quality standards for compost produced from technologically treated source-separated waste is a must. Source separating compostable and recyclable materials also can help communities financially, ORCA maintains, by diverting up to 68 percent of the waste stream from incineration without impacting the calorific value and by reducing landfill fees.
Aside from composting their or-ganic wastes, Europeans are showing increasing interest in anaerobic digestion. Also referred to as methanization or fermentation, this process involves the breakdown of or-ganic materials in the absence of oxygen to a mixture of methane and carbon dioxide gases. This "biogas" can be converted to heat or used to power vehicles.
The two biological processes are complementary. First, they require different types of waste: composting, an aerobic process (it occurs in the presence of free oxygen), is suited for structured and ligneous materials, whereas anaerobic digestion can treat wet, compact kitchen and res-taurant waste. Second, the residue from anaerobic digestion requires composting, possibly with chipped green waste, for optimal recycling.
Biological waste treatment can provide benefits beyond waste management. In recent decades, Europe has experienced serious deterioration of its soil quality, mainly from erosion. The humus produced by well-managed organic recycling processes can protect soils threatened by erosion, reduce the need for peat, minimize pesticide and fertilizer ap-plication and repair depleted land.
Converging Policies ORCA, the Europewide voice of composting, is striving to shape an integrated waste management policy in Europe that ac-centuates organic waste recovery and treatment. Its approach in-cludes identifying and developing new markets, appropriate technologies and quality control methods; disseminating information on sound composting; and spreading the European perspective among individual nations.
The 15 countries that belong to the European Union (EU) are obligated to imbed their national policies in those of the EU and base their national waste laws on Waste Direc-tive 91/156/EEC. As a result, environmental law in member states is taking on an increasingly Pan-Euro-pean dimension, although standards and implementation methods vary from country to country. As yet, no directive on compost production and use exists, but the legal context for a directive and for composting standards is being explored and standardization activities have begun.
In the meantime, several countries are legislating for greater use of their organic wastes. Nearly two-thirds of these wastes stem from vegetable, fruit and garden (VFG) sources; the rest include nonrecyclable paper and cardboard and, increasingly, biologically derived plastics.
In the Netherlands, separate bio-waste collection was tested from 1986 to 1990. The system proved so successful that it became national policy in 1990, when the first Bio-waste Action Program was established to coordinate the decentralized activities of provinces and mu- nicipalities, to expand processing capacity and to produce high-quality compost.
The Environmental Management Act, which came into force in Jan-uary 1994, has provisions for banning from landfills certain "priority substances," including biowaste, in order to drastically reduce the volumes of waste requiring final disposal. Since 1994, municipalities have been required to collect source-separated organics from households on at least a biweekly basis for composting. The 1996 target is to collect and process 1.7 million metric tons of the nearly 2.3 million metric tons of biowaste generated per year.
Another leader is Austria, where an ordinance mandating separate collection of biowaste took effect in January 1995. After promulgation of the ordinance in 1992, municipalities were given three years to develop the necessary infrastructure. Expan-sion of the collection network across Austria is expected to be complete in 1996.
In Germany, a draft composting ordinance was anticipated by this winter. The ordinance will be based on the Closed-Loop Economy and Waste Management Act of 1994, which shifts the policy focus from waste disposal to materials recovery and recycling and gives waste law much broader applications.
The ordinance will address issues such as compost applications and hygiene and will set compulsory quality standards for all facilities and processes. The existing guidelines in Germany (see table on page 37), which were developed by private and state organizations in the ab-sence of any national standards, will be replaced or rendered basically meaningless by these new standards. Residues from anaerobic di-gestion also are expected to be subject to the ordinance.
Separate collection and treatment of organic wastes became an essential part of German waste management with the passage of the Tech-nical Guideline for Municipal Waste (TASi) in April 1993. TASi states that "biological treatment of separately collected biowastes is to be en-sured." Requirements are laid down for feedstock delivery and pretreatment, compost quality, facility construction and operation and compost use. Similar requirements are included for anaerobic digestion.
A Soil Protection Act also is anticipated this year, according to Dr. Mach of the Federal Environ-mental Agency in Berlin. It will set limits for the application of organics with nutrient content, such as sewage sludge, liquid manure and compost.
In France, the poor image of compost from municipal waste has led to the demise of important, traditional markets. As of mid-1995, only about a dozen programs existed for separate organic waste collection, most of which were in the testing stage. Whereas the composting of source-separated organics is still emerging, green waste composting is doing well. The French Agency for the Environment and Energy Management is hopeful that the generally good-quality compost from green waste will win greater acceptance for compost from other waste products.
Switzerland, though not a member of the EU, has been a pioneer in establishing an overall waste management concept in which biowaste treatment plays an important role. The country's 1986 Material Ordinance prescribes quality standards that limit the heavy metal content in compost, and the 1990 Technical Ordinance on Waste makes the Swiss cantons responsible for separate collection and recycling of reusable municipal solid waste.
Putting Down Roots Programs and facilities that expand the use of organic wastes are proliferating throughout Europe. Following are highlights of activities in a few countries.
The Netherlands. In 1929 the Netherlands established a composting company, VAM, to produce compost from urban waste for use on infertile soils. In the early decades, the country's household waste consisted of 70 to 80 percent organic matter. Problems with compost quality developed in the 1960s, however, when heavy metals were detected. Despite mechanical sorting, the compost failed to keep pace with the government's increasingly stringent quality requirements, and the composting of sorted municipal waste has been abandoned, according to Willem de Feyter, former managing director of VAM.
After separate collection and composting of biowaste was expanded on a large scale, government entities used emergency procedures to bring several processing plants on line rapidly in 1993 and 1994. Source-separated VFG collection was provided to 67 percent of the households in the Netherlands in spring 1994 and is expected to be available to 89 percent of the households and 100 percent of the municipalities by 1996.
Composting has been the Dutch tradition, according to De Feyter, and it continues to be the main choice because of the country's experience and its existing infrastructure. "Until recently, composting was done outdoors," he said, but "85 percent of ... composting companies [that] have operated since 1990 compost in enclosed spaces." The few companies that use open-air processes draw air down through the pretreated bio-waste in a concrete-walled area. Biofilters help to control odors.
Only one facility, near Tilburg, is an anaerobic system with subsequent composting of the fermented residue. It uses the same gasification technology as an operational plant in Amiens, France. Currently, 10 to 15 percent of all facilities in the Netherlands are privately owned; most are run by firms owned by local or national government bodies.
Austria. Austria's goal is to boost the recovered percentage of compostable waste - including kitchen scraps from homes, restaurants and cafeterias as well as green waste from yards, parks, cemeteries and city streets - from nearly 65 percent in 1994 to 90 percent by 2000. In most communities, the biowaste is separated into biobins that are picked up weekly in the summer and every two weeks in winter. Densely populated districts of Vienna have a drop-off system. In addition, Austrians often take their yard wastes directly to the composting facilities.
Biobin collections in Austria averaged 29 kilograms per person in 1994 and are expected to capture 50 kilograms per person by 1996. The 297 biowaste composting facilities and 200 facilities dedicated to green waste provided sufficient capacity in 1994, together with decentralized private and agricultural composting sites. By 1996 there are to be 350 biowaste facilities, but the Federal Ministry for Environment says the number must continue growing to meet the goal of processing 1.14 million metric tons in 2000.
Austrian residents who compost their organic wastes year-round at home are not only exempt from the biobin collection but are offered a fee rebate in some communities. Approximately 550,000 metric tons are processed by "self composting." It's forecasted that an average of 39 percent of all residents will practice backyard composting in 1996.
Germany. In Germany, biological treatment of wastes is becoming one of the pillars of municipal waste management. In 1993 alone, Germany added more than 400,000 metric tons of new facility capacity. The total processing capacity is projected to more than double from the spring of 1994 to the end of 1995.
Approximately 400 composting facilities are in operation, about half of which are operated by members of the Federal Association of the German Disposal Industry (BDE). Processing typically takes place in windrows in enclosed buildings, although systems available on the market also include drums, bins, tunnels and silos. The trend is toward capacities of more than 20,000 metric tons per year and higher quality standards.
Where processing capacity is available, separate biowaste collection already has been or is being introduced by cities and counties. Expansion of separate collection programs throughout Germany will depend on the extent of feasible opportunities for compost use. This flexibility is permitted by TASi.
Anaerobic digestion still plays a minor role in Germany but is expected to gain importance in the future, particularly in heavily populated areas where the waste has a high moisture content.
This relatively new technology is more susceptible to operational problems than composting because of the complicated biological process. However, it is economical to operate as a result of the recovered energy, according to sources including H.P. Fahrni of the Swiss Federal Office of the Environment, Forests and Landscape.
Switzerland. In 1993, when Switzerland generated about 2.8 million metric tons of urban solid waste, 350,000 metric tons of organic material were separately collected and composted. Biogasification is gaining increasing attention. Two industrial-scale plants near Zurich use a Swiss technology for anaerobic digestion and a third facility reportedly was under construction in 1995. Several projects are in the planning stage. Integrated biomethanation and composting of dried, sorted household wastes is being studied for a project in Geneva.
The Hitch: Viable Markets "High-quality compost has huge market potential as a soil ameliorant in gardening and agriculture and many other applications," according to ORCA. However, it must compete with a flood of other organic residues needing to be recycled, such as sewage sludge, plant biomass and animal manures.
Also, the benefits of compost use are clouded by negative perceptions that compost is a waste material containing unavoidable pollutants and that users should be compensated for disposing of it. When this image was fanned by the press in the Netherlands last winter, the Dutch Information Service for Agriculture responded with an official statement that VGF compost is an organic soil improver which meets all legal parameters.
Organizations in different countries devise strategies for market recognition and development of compost products. Examples are VLACO in the Flemish provinces of Belgium, the Consortio Compostatori in Italy, ARTEGRUS in Spain, the National Compost Development Association in the U.K., the Dutch Association of Waste Processors and the Federal Compost Quality Association in Germany. In addition to disseminating correct information about compost and its applications, these organizations help their national governments set quality guidelines and standards that are the key to successful marketing.
ORCA also has defined basic criteria for the acceptability of feedstock in biowaste treatment. First and foremost is environmental safety, meaning that the waste should not adversely affect the biological process, the biota in composted-amended environments nor the physical and chemical properties of compost-amended soil.
Sustaining the biowaste boom in Europe, according to ORCA, depends upon a balance of maximum diversion of organic material from landfilling, minimal overall solid waste management costs and production of marketable compost.
A facility in Baden-Baden processes 6,000 metric tons of biowaste per year; one to be completed in 1996 in Munster is sized for 11,000 metric tons per year.
Backyard composting is promoted in Germany's less urban regions. State and local governments provide their citizens not just with clear instructions but also with "active assistance" in the form of hotlines, mobile chippers and subsidized composting bins.
Spain and Belgium. Other countries are upgrading their approach to biological treatment of waste. In Spain, for example, 20 composting plants with low operating standards and a poor-quality compost product reportedly are being closed, while several new facilities are expected to be built to utilize a waste stream that contains as much as 50 percent organics. In Belgium, a network is being developed to collect and process source-separated VFG waste in Flanders. Three enclosed facilities processed the 100,000 metric tons of VFG collected in 1994, but seven are to be operational by the end of 1997 to provide a capacity of 270,000 metric tons collected from 40 percent of the population. Both composting and biogasification systems are planned to meet the targets set by the Belgian provinces.