Grassroots groups have been very successful in defeating incinerator proposals. Since 1997, only two trash incinerators have been built in the US (Dearborn, Michigan in 2000 and Anahuac, Texas in 2002). Groups have been successful because they organized and got the word out about what incineration really means for communities: toxic emissions and residual ash, high construction costs, and the destruction of valuable resources. And they have successfully promoted the alternatives to burning waste: recycling, composting, and recovering waste components.

The incinerator industry has, in fact, learned something from the successes of grassroots community groups: If they want to build incinerators, they're going to have to come up with new ways to spin them. So what we're seeing are all sorts of "new" ideas and proposals.

The hottest area of activity is in plants designed to produce energy. In the aftermath of the California energy crisis and the 9-11 terrorist attacks, strong sentiments to reduce our dependence on foreign oil have resulted in a rash of proposals to build energy-generating plants that don't rely on oil. Many of these plants are referred to as "green energy" or "eco-energy" projects. To a lesser extent, we are seeing an old favorite - waste-to-energy plants.

Waste-to-energy projects are especially devious because there are legislative efforts in Massachusetts and at the national level to define garbage incinerators as a source of "renewable" energy. If these efforts are successful, the most common incinerator used to burn household garbage - the mass burn incinerator - will be included with solar and wind projects as renewable energy sources!

These new proposals have several characteristics: they are being put forward to solve the solid waste "crisis"; they are being sold as an alternative to incineration; and many recover energy. While these plants are not technically incinerators, they cause many of the same pollution problems. The old rule still applies: If it looks like a duck, walks like a duck, and sounds like a duck, there's a good chance it's a duck.

Biomass Conversion

One of the most popular renewable energy projects is the "energy from biomass" proposal. Biomass traditionally refers to fuels derived from wood, agriculture and food-processing waste or from crops grown specifically to produce electricity. However, in this new wave of non-incineration proposals, we're seeing a variation that involves converting household trash into a biomass - like fuel. These projects generally entail collecting household garbage at the curb, without source separation or recycling, and then removing metals, glass, plastic and other waste items that are not conducive to biomass processing. The remaining waste, consisting largely of mixed paper, food, wood and yard waste, is then run through a "biomass" conversion process that generates a fuel product.

Some proposals are designed to generate ethanol for sale. The concern here is purity of the ethanol product. Historically, bioconversion processes have been used mostly with agricultural waste streams that are more uniform in composition, have higher cellulose content and fewer material handling problems than municipal solid waste streams. It is not at all clear that this new application can produce a high quality ethanol product that can be marketed, especially given the range of contaminants present in household garbage.

The more common fuel product proposed with most biomass plants is called "refuse derived fuel" or RDF. In this instance, the biomass waste is converted into pellets that are sold as fuel to be burned in incinerators or boilers to recover energy. In these cases, you still have toxic emissions and residual ash contaminated with heavy metals and dioxins, though at slightly lower levels than in a mass burn incinerator.

This process has not been used with municipal solid waste on other than a small pilot scale and it is likely that the costs have been underestimated, perhaps substantially. But the major problem with this process is that it would destroy vast quantities of materials that could be either recycled or composted.

Pyrolysis and Gasification

Two other technologies being promoted as clean alternatives to typical trash incinerators are pyrolysis and gasification. Pyrolysis is a thermal destruction process that burns waste in the absence of oxygen. A plasma arc is often used to generate the heat at high temperatures. This process produces a mixture of gases, liquids and solids, some of which will include toxic chemicals depending on the make-up of the original waste mixtures. With household trash, the emissions and solid residuals can be expected to include heavy metals, dioxins, and other contaminants typically found when household trash is burned.

Gasification is a similar thermal destruction process, only in this case small amounts of oxygen are present during the heating process, which also occurs at high temperatures. In this process, often called "starved-air gasification," a gaseous mixture is produced that will again include toxic chemicals depending on the make-up of the original waste mixture. If household trash is gasified, emissions will again include heavy metals, dioxins, and other contaminants.

Both of these technologies are considered to be in the developmental stage with regard to their application to household trash. As practical matter, the health and environmental concerns that these processes raise seem no different than if the waste were burned in a traditional incinerator. With both of these systems, toxic gases are formed during the treatment process that are similar to those found during the combustion of household trash in a traditional incinerator and are released out of stack. Some - but not all - of these emissions may be captured by pollution control equipment. With pyrolysis, solid residue remaining after the treatment may contain toxic chemicals similar to those found in ash from traditional incineration.

Co-Generation Plants

Co-generation is the production of heat and electricity by the same energy plant. In a conventional power plant, coal, oil, or natural gas are burned at high temperatures to generate steam. The pressure from the steam turns a turbine that produces electricity. Only about 30 percent of the energy of the original fuel is converted to steam in this process. The rest is wasted. In a co-generation plant, the excess heat is captured as low temperature steam is given off by the turbines. This steam can be used to generate heat but cannot be transmitted very far. It is used mostly for nearby factories such as pulp and paper mills that require low temperature heat for their production lines or for space heating in buildings.

The new wave of proposals include co-generation plants that burn fuels other than coal, oil, or natural gas. Some proposals are for burning "biomass" such as wood waste, agricultural waste, peat moss and a variety of other wastes, including household garbage that has been converted into "biomass" as described above. While these plants may generate less sulfur oxides or greenhouse gases such as carbon dioxide, depending on the fuel burned, they are still incinerators that generate emissions, some of which will include toxic chemicals, depending on the makeup of the fuel that is burned with household trash, the emissions and solid residuals can be expected to include heavy metals, dioxins and other contaminants.