Turning trash into gold
Largely unseen, municipal waste management is a major factor in the quality of life in our cities and towns. Collecting, transporting, processing and disposing of waste - generally in landfills - not only is one of the largest components of municipal expenditure ($2.1 billion in 2006), it is potentially one of the most environmentally damaging.
Biodegradable wastes in landfills release large amounts of methane, a greenhouse gas 70 times more powerful than carbon dioxide (CO2) in terms of its impact on global warming. Other gasses such as nitrous oxide emitted when plastics and textiles are burned are 300 times more powerful than CO2. And more CO2 is emitted during the collection and transportation of waste to processing sites at landfills and incinerators.
Chemicals from degrading waste leak into local aquifers; contaminate water supplies; poison soils; and release other carcinogenic agents and particulate matter that can seriously affect human health. Landfills harbour disease-carrying rats, flies, and other vermin and generally degrade local eco-systems.
Small wonder that resistance is often encountered when new landfill sites are being sought.
Municipal Waste to Energy
Until recently, there was little concern about the availability of landfills to accommodate growing volumes of municipal wastes. But with the growth of Canada’s cities, fewer options for new landfill sites close to urban areas, and rising concerns about greenhouse gas emissions have prompted many cities to look to other ways to manage solid wastes, such as incineration.
New and innovative waste-collection and waste processing systems - far cries from the polluting incinerators and vast landfills of the past - can help reduce waste volume and minimize environmental and health impacts.
Incineration is seen as an attractive option as an effective incinerator releases only a third the amount of greenhouse gases as do landfills handling the same volume of waste. And the energy created by burning garbage creates less greenhouse gases than does energy produced by burning fossil fuels because it does not release carbon that was stored deep underground.
Waste-to-energy is hardly new. Cultures have burned trash to create energy (heat) and to manage waste for centuries. Trash incinerators have been in place in major cities since the 1800s, but the technology by and large fell out of favour due to concerns over air quality and emissions, as well as an inability to compete with cheap power prices in some regions.
Waste-to-energy (WTE) refers to any waste treatment that creates energy in the form of electricity or heat from a waste source. Such technologies reduce or eliminate waste that otherwise would be transferred to a "greenhouse gas" emitting landfill. Most WTE processes produce electricity directly through combustion, or produce a combustible fuel commodity, such as methane, methanol, ethanol or synthetic fuels.
Municipal wastes combusted directly to produce heat and/or power come from residential, commercial and public service sectors (including hospital waste) collected by local authorities. A third of the 35 million metric tonnes of waste were handled by Canada’s waste management industry in 2006 comes from residences, and this volume is rising at 3% per annum. The rest comes from non-residential sources, and this volume is growing at 11% per annum. So there is little fear of available feedstock running out.
While there are incinerators in Canada turning municipal solid wastes into marketable energy and other by products, they are few in number.
A waste-to-energy facility in Burnaby British Columbia that opened in 1988 burns about 20 per cent of the Lower Mainland’s garbage, mainly from the North Shore, Burnaby and New Westminster, according to Metro Vancouver. Every year, the facility turns approximately 280,000 tonnes of garbage into 900,000 tonnes of steam, a portion of which is sold to a nearby paper recycling facility to eliminate the use of fossil fuels.
The typical incineration plant for municipal solid waste is a moving grate incinerator which can handle up to 35 tonnes of waste per hour, and can operate 8,000 hours per year. Such plants can generate electricity and heat that can replace energy from other fuels and can be sold to the regional electric or district heating supply for industrial customers. Modern incinerators reduce the volume of the original waste by 95-96 %, depending upon composition and degree of recovery of materials such as metals from the ash for recycling.
Everyday the Burnaby British Columbia WTE plant turns out: 960 tonnes of steam sold to nearby paper plant; 400 megawatt-hours of electricity; 135 tonnes of bottom ash (used in road building and landfill cover); 28 tonnes of fly ash (disposed at landfill); and 27 tonnes of scrap metal (recycled into reinforcing steel).
Several other Canadian cities are also exploring waste to energy systems.
Plasco Energy Group Inc. of Ottawa will presently receive a letter of intent from Ottawa City Council to build, own and operate a 400 tonne-per-day waste conversion facility that will process residual household waste that would otherwise be sent to landfill.
Edmonton will be home to the world’s first industrial scale facility to produce biofuels from municipal solid waste. The City has signed a 25-year agreement with GreenField Ethanol, Canada’s largest ethanol producer and Enerkem, a leading biofuels technology company.
The $70 million biofuels facility will initially produce 36 million litres of biofuels per year and reduce Alberta’s CO2 footprint by more than 6 million tonnes over the next 25 years - the equivalent of removing 12,000 cars off the road every year.
EnQuest Power Inc. is actively seeking to build a municipal waste to energy facility in Sault Ste. Marie, Ontario based on its technology to transform organic material – wood and paper waste, sewage sludge, municipal waste, even coal - into gas, electricity, and other usable forms of energy. The company states the process is highly efficient, environmentally friendly, and leaves virtually no residue.
In early 2008, the governments of York Region and Durham Region approved a proposal for a WTE facility in Clarington Ontario and are now seeking the required Ministry of the Environment approval. The estimated cost for the facility is Cdn $250 million.
Metro Vancouver is exploring options for more waste-to-energy facilities to dispose of the region’s 3.6 million annual tonnes of garbage. Such facilities are needed because its current landfill at Cache Creek will close in 2010. The waste management committee of Metro Vancouver says the proposed plants are a better way to deal with solid waste than landfills because they will convert garbage to gas and steam, which can be sold.
Vancouver Councilor Suzanne Anton believes the technology is a viable solution to the region’s trash problems. "There are miniscule emissions," she said in a recent interview. "They are not like the old incinerators pumping smoke through the Fraser Valley. "New waste-to-energy facilities are light years different from the past. In Europe, they put them in the middle of their towns.
Not everyone agrees. Paul Connett, a leading expert in waste management, and professor emeritus at St. Lawrence University in Canton, N.Y. told a Vancouver audience recently that industry is making false claims of emitting zero dioxins (chemical compounds which accumulate in humans) and zero particulates (extremely small matter which penetrates lung tissue).
"They are incinerators in disguise. They convert solids into gases and then burn the gases. It leads to the same problems as incinerators," he said in a recnt interview. Connett predicts a dramatic increase in asthma rates in the Fraser Valley if the plants are built," noting also that the plants will cost up to $2 billion.
The health concerns are valid but diminishing
Concerns over the health effects of dioxin and furan emissions have been lessened to some extent by advances in emission control designs and stringent governmental regulations, but they are not totally eliminated. Older Incinerators can also emit varying levels of heavy metals such as vanadium, manganese, chromium, nickel, arsenic, mercury, lead, and cadmium, which can be toxic at very minute levels.
According to Greenpeace International, WTE facilities are also among the largest sources of dioxin emissions in industrialized countries. Dioxin is a by-product of burning polyvinyl chloride (PVC) and other plastics, and has been linked to cancer and other health problems. Greenpeace advocates for phasing out WT facilities in favour of improving recycling rates that reduce the waste stream in the first place.
Incinerator Bottom Ash (IBA) has high levels of heavy metals with eco-toxicity concerns if not reused properly. IBA reuse is still in its infancy and is still not considered to be a mature or desirable product, despite additional engineering treatments.
These problem areas are well known and efforts are being made to address them directly, both in terms of design and in process management. For example, fifteen years ago, 18 Swedish waste-to-energy plants emitted a total of about 100 grams of dioxins every year. Today, the collective dioxin emissions from all 29 Swedish waste-to-energy plants amounts to 0.7 of a gram, a clear indication that Europe has made great strides with respect to toxic emissions reductions from such facilities.
Waste to Energy is hot news elsewhere
There are over 400 waste-to-energy plants in Europe today that process some 50 million tonnes of municipal solid waste per annum, generating an amount of energy that can supply electricity for 27 million people or heat for 13 million. In fact, waste incineration is more common in Western Europe and some Asian countries than anywhere else in the world. The "classic" incineration countries are Belgium, Denmark, Germany, France and the Netherlands, in Europe, plus Japan in the Asia market.
Upcoming changes to EU legislation will have a profound impact on how much further the technology will help achieve environmental protection goals. To cope with the rising volumes of waste to be treated and disposed of as a result of the European Union Landfill Directive, this number will significantly increase in the next 7 years, with over 100 plants or lines added by 2012.
There will be more WTE Plants
With the increased price of fossil fuel energy and growing interest in alternate or renewable sources of energy, it is clear WTE facilities will become commonplace in many cities and towns throughout the world. Technological improvements have rendered such facilities much more environmentally acceptable than their older predecessors.
In addition to declining health risks associated with WTE systems, the rising costs of conventional fossil fuels is making this rediscovered form of energy generation cost competitive.
Several companies are beginning to explore other uses for landfill gas. Waste Management announced in April that it will build the world’s largest facility to capture landfill gas at the Altamont Landfill near Livermore, Calif. When it begins operating in 2009, the plant will turn landfill gas into liquid biogas to fuel its 300 waste and recycling trucks in California. See article World’s largest landfill gas facility slated for San Francisco.
The project carries an initial price tag of $15 million but will produce nearly 13,000 gallons of liquid fuel each day and reduce the company’s greenhouse gas emissions by more than 30,000 tons per year.
Lynn Brown, vice president of corporate communications at Waste Management, says the project is a part of the company’s plan to have some kind of gas-to-energy plant installed at all its landfills by 2012. Where it can’t feasibly generate electricity or put the gas into service in a direct-use application, the company wants to be able to create liquid biogas and may even look to turning landfill gas into diesel fuel.
It is clear that modern, clean incinerators not only can reduce the volumes of waste destined for landfills but also can reduce GHG emissions and provide economically viable heat and electricity for homes and businesses.
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