What’s wrong with burning of waste in incinerators? It reduces the volume of the waste going to landfills, eliminates or reduces the dependency on landfills, makes waste management easier, and unlike landfills, it only takes a few minutes or so for the waste to totally disappear from the environment. This sounds like a dream solution for managing waste and can be compared with the song ‘Imagine’ by John Lennon, where he paints a picture of a world without war, greed, and hunger. Just add the word ‘waste’ to that list and it could easily be a song about incineration. So why is incineration not adopted by most countries to tackle waste related problems and why are there no stories of a successful incineration plant? The answer is simple. Research on various issues relating to incineration shows that far from being a clean and efficient way to manage waste, it has a host of direct and indirect negative impacts. Let’s start with what incineration actually means.
What is incineration?
In its most basic description, it is the burning of waste. Incineration is a thermal decomposition of organics in the presence of oxygen at higher temperatures (Figure 1)1. Bunkers are used to store the waste required to run the incineration plant. Once the pretreatment of the waste is completed, the waste is fed into the combustion chamber (boiler) wherein high-pressure steam is generated. This steam is then navigated to pass through heat exchangers and turbines to generate heat and electricity. The waste is converted to ash, which is about 30-40% of the waste of the original waste. The process of burning produces toxic smoke, or flue gas2, which passes through various cleaning equipment and is released into the atmosphere via the stack.
Figure 1: Different phases in a waste incineration plant
Incineration encourages waste production
Most of the materials, currently disposed of in incinerators, can be reused, recycled or composted. Incineration plants demand a guaranteed continuous stream of waste to run the plant, functioning as a major factor to generate more waste and hinder waste reduction. Incineration not only destroys these valuable materials, but it also irretrievably transforms them into exhaust fumes, poisons, ashes, dust, and heat. Incinerators legitimise the generation of waste since more waste is required to keep the incinerator functioning. They represent unfettered consumerism, wasteful packaging, and irresponsible producer behaviour. They also take governments down the path of short-term waste management practices and places cities on a path of dependence on an expensive and inefficient technology.
Incineration is harmful for health
All the excretions from incineration are useless and even dangerous as the exhaust gases heat up the atmosphere. Poisonous exhaust gases contribute to the ever-increasing burden on health: allergies, immunodeficiency, diseases, pseudocroup, and contamination of food chains. Nitrogen oxides (NOx), mercury, dioxins, and ultra-fine particles are some of the pollutants that are released by incineration of discarded materials. These are known to cause cancer, respiratory diseases, and cardiovascular risks. Even the most advanced pollution control devices cannot eliminate toxins, in particular, the fine dust passes through the filter, and these particles are deeply breathed into our lungs. It is true that the flue gas filters have improved, but there are no filters that hold everything back. Even small amounts of these highly toxic substances are carcinogenic and add up to the existing air pollution.
Pollution control is expensive and problematic
Incineration generates volatile organic compounds, nitrous oxides, acid gas, and particulate matters. To ensure that these do not escape during the incineration process, pollution control devices are added. A pollution control device could be an exhaust fan, wet scrubber (passes fumes through water), dry scrubber (uses lime as a filter), gravity settler (to settle heavier particles), and dilution equipment (to reduce the concentration of smoke), among others. However, it is important to know that these devices cannot stop pollution. They can reduce the concentration in gases and collect the solid matters in the ash. Adding regulatory standards and controls do not reduce pollution. Spot checks are the real way to monitor if incinerators are meeting the regulation standards, but this is expensive and not possible for a majority of the cases. A recent study revealed how even the so-called state of the art incinerators emit dangerous pollutants far beyond toxic emissions limits.3
Incineration is a waste of energy
Waste incineration is the dirtiest and least efficient way to generate electricity. Municipal waste in India has very low calorific value - between 600 and 800 kcal/kg - in contrast to the required value of 1400 kcal/kg. Coal power plants are widely termed as the most air-polluting source of energy, but the data shows how much worse trash incinerators are for air quality compared to a coal power plant. Waste incinerators release 28 times as much dioxin than coal4, 2.5 times as much carbon dioxide (CO2)4, twice as much carbon monoxide5, three times as much nitrogen oxides (NOx)4, 6-14 times as much mercury, nearly 6 times as much lead, and 70% more sulfur dioxides4 (Figure 2).
Figure 2: Number of times more polluting waste incineration is compared to coal
Incineration is not final disposal - It required landfills
It is a myth that waste incinerators eliminate the need for a landfill. About 30% of pollutants still remain as fly ash, bottom ash, boiler ash, slag and wastewater treatment sludge, deposited in landfills for generations to come. Residual ash contains a wide variety of toxic compounds and elements like heavy metals and dioxins and these toxic pollutants can leach into the groundwater, rivers, and soil.
Incinerators shift the burden of waste to certain communities
Incinerators require large amounts of land to set up the plant and store waste and the incineration residuals. Invariably, these are located in and around low-income communities, burdening residents with high toxicity, accidents, and noise. This shifts the burden from producers and consumers to those communities that have very little to do with the generation of this waste. Most low-income groups generate less waste per capita than high-income groups but are subject to the negative impacts in terms of polluted groundwater, toxic air, and noise.
Incineration is a very expensive technology
Waste incineration is a financial burden for the host cities as it is an expensive way to manage waste, even if it can generate energy, it is in the least efficient manner. The cost of an incineration plant is twice the cost of coal-fired power plants. The technology might be lucrative for the companies that design them, but it is not so for the local government or residents. According to UNEP and International Solid Waste Association (ISWA), waste incineration is especially unfeasible for low and middle-income countries due to its cost-prohibitive nature and unsuitable waste composition. The financial incentives provided under the umbrella of renewable energy schemes is one of the key factors that help waste incineration plants to self sustain. One of the key assumptions that has been made to classify waste incineration as renewable energy is that CO2 from non-fossil fuel sources do not matter because of its short cycle nature. The assumption is false because all the sources of CO2, irrespective of their origin, contribute to climate change. For example, plastic is burned in the incinerators along with other waste but in reality, most of the plastic is nothing but processed fossil fuel.
A rose by any name...
The recent trend followed by incineration companies is presenting the same technology under the names ‘state of the art incineration’ and ‘high heat technologies’. These technologies have the same downfalls as conventional incinerators and these overdimensioned waste burning facilities are expensive to build, polluting, don’t eliminate the need for a landfill, squash reduction, reusing, recycling, and composting programs, and generate fewer and dirtier jobs compared to zero waste programs. In contrast, recycling residual materials lets one recover primary raw materials, and avoid toxic and CO2 emissions. So there is so much wrong with burning our waste. Waste incineration is not only a gigantic waste of valuable materials but also greater danger to our health, environment, and economy. The perceived benefits of waste incineration are simply not worth the risk.
1. Incineration of Municipal and Hazardous Solid Wastes https://bit.ly/2WgGuBU
2. Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator.
3. Hidden emissions: A story from the Netherlands https://bit.ly/2FJCPax
4. Emissions & Generation Resource Integrated Database (eGRID) https://bit.ly/2qYvp7F
5. Waste-To-Energy: Dirtying Maryland’s Air by Seeking a Quick Fix on Renewable Energy? https://bit.ly/2R75A25