What we’re scrubbing out of our emissions
We have reduced the undesirable emissions from our plants by 99% over the last decade. And we’re still making progress toward zero emissions. Our principal targets include:

Mercury

• Mercury is a heavy metal that can eventually accumulate in organisms when released into an ecosystem.

• Mercury has been almost completely removed from the trash but is still found in some items, such as thermometers. Since mercury is an element and naturally occurring, it cannot be destroyed, only collected.

• Over 95% of the mercury in the waste that does come to our facilities is reduced by absorbing it in a special carbon injection system. Mercury emissions from EfW facilities are less than 4% of the total emissions inventory in the U.S.

Dioxin

• Dioxins occur naturally in the environment from sources such as volcanic eruptions and forest fires.  They also are produced by man-made sources such as coal fired utilities, metal smelting, diesel trucks, land application of sewage sludge, burning treated wood, and trash burn barrels.  Dioxins are also found in small amounts from the common smoke of cigarettes and barbeques.

• Dioxins are produced in small concentrations when organic material is burned in the presence of chlorine.

• Combustion of municipal solid waste produces less than 1% of all dioxin emissions.

• Dioxins are destroyed in the EfW process through controlled high-temperature combustion at over 2,000 degrees Fahrenheit. 

Nitrogen Oxide (NOx)

• NOx is the generic term for a group of highly reactive gases, all of which contain nitrogen and oxygen in varying amounts.

• The primary man-made sources of NOx are motor vehicles, electric utilities, and other industrial, commercial, and residential sources that burn fuels.

• NOx is one of the main ingredients involved in the formation of ground-level ozone, which can trigger serious respiratory problems and contributes to formation of acid rain.

• NOx emissions are minimized in the EfW process with sophisticated combustion controls and further reduced by injecting a chemical reagent such as ammonia into the process.

Covanta’s successes in emissions reductions

Over the last decade, the EFW industry has successfully reached a 99 % reduction in dioxin emissions and now accounts for only one-half of one percent of the national dioxin inventory.  Mercury emissions have been decreased by 95%and currently make up only two percent of the national inventory of manmade mercury emissions.

Covanta research teams are also constantly looking at ways to reduce our NOx emissions. Over the years we have made great strides; since 1990 we have reduced our NOx emissions by 17.6% on a tons per year basis. Now, we have developed LN and VLN technologies that offer even greater reductions in NOx emissions (to approximately half of the currently low levels) and help continue to support Covanta's efforts towards clean, low emission waste disposal and energy generation.

Note:

1. This amount of 837 lbs/MWh does not reflect the avoided methane emissions from landfills or CO2 emissions that would come from fossil fuels sources to generate the same amount of electricity. Overall, Energy-from-Waste are net reducers of Greenhouse Gases (GHG).
2. Covanta has developed two technologies (LN/VLN) that will cut NOx emission to approximately half of the already low regulatory limits.