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Negative Impacts of Incineration-based Waste-to-Energy Technology, posted in Environment, Waste Energy.


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Negative Impacts of Incineration-based Waste-to-Energy Technology

News » Energy | Biofuels | Environment | Hydrogen | Solar | Transportation | Wind
September 8th, 2008 - View Comments

Waste Energy Pollution Despite being an attractive technological option for waste management, combustion-based processes for municipal solid waste (MSW) treatment are a subject of intense debate around the world. In the absence of effective controls, harmful pollutants may be emitted into the air, land and water which may influence human health and environment. Although incineration of municipal waste coupled with energy recovery can form an essential part of an integrated waste management system, yet strict controls are required to prevent its negative impacts on human health and environment.

Incineration technology is the controlled combustion of waste with the recovery of heat to produce steam that in turn produces power through steam turbines. MSW after pretreatment is fed to the boiler of suitable choice wherein high pressure steam is used to produce power through a steam turbine. Pyrolysis is extensively used in the petrochemical industry and can be applied to municipal waste treatment where organic waste is transformed into combustible gas and residues. Gasification is another alternative which normally operates at a higher temperature than pyrolysis in limited quantity of air. While both pyrolysis and gasification are feasible technologies to handle municipal waste, commercial applications of either technology have been limited.

Incineration-based technologies have been a subject of intense debate in the environmental, social and political circles. This article evaluates incineration on the basis of three parameters – environmental, human health and economic impact – and proposes an integrated mechanism to maintain a fine balance between energy recovery and environmental concerns.

Environmental Issues
The incineration process produces two types of ash. Bottom ash comes from the furnace and is mixed with slag, while fly ash comes from the stack and contains components that are more hazardous. In municipal waste incinerators, bottom ash is approximately 10% by volume and approximately 20 to 35% by weight of the solid waste input. Fly ash quantities are much lower, generally only a few percent of input. Emissions from incinerators can include heavy metals, dioxins and furans, which may be present in the waste gases, water or ash. Plastic and metals are the major source of the calorific value of the waste. The combustion of plastics, like polyvinyl chloride (PVC) gives rise to these highly toxic pollutants.

Toxics are created at various stages of such thermal technologies, and not only at the end of the stack. These can be created during the process, in the stack pipes, as residues in ash, scrubber water and filters, and in fact even in air plumes which leave the stack. There are no safe ways of avoiding their production or destroying them, and at best they can be trapped at extreme cost in sophisticated filters or in the ash. The ultimate release is unavoidable, and if trapped in ash or filters, these become hazardous wastes themselves.

The pollutants which are created, even if trapped, reside in filters and ash, which need special landfills for disposal. In case energy recovery is attempted, it requires heat exchangers which operate at temperatures which maximize dioxin production. If the gases are quenched, it goes against energy recovery. Such projects disperse incinerator ash throughout the environment which subsequently enter our food chain.

Incinerator technological intervention in the waste stream distorts waste management. Such systems rely on minimum guaranteed waste flows. It indirectly promotes continued waste generation while hindering waste prevention, reuse, composting, recycling, and recycling-based community economic development. It costs cities and municipalities more and provides fewer jobs than comprehensive recycling and composting and also hinders the development of local recycling-based businesses.

Human Health Concerns
Waste incineration systems produce a wide variety of pollutants which are detrimental to human health. Such systems are expensive and does not eliminate or adequately control the toxic emissions from chemically complex MSW. Even new incinerators release toxic metals, dioxins, and acid gases. Far from eliminating the need for a landfill, waste incinerator systems produce toxic ash and other residues.

The waste-to-energy program to maximize energy recovery is technologically incompatible with reducing dioxins emissions. Dioxins are the most lethal Persistent Organic Pollutants (POPs) which have irreparable environmental health consequences. The affected populace includes those living near the incinerator as well as those living in the broader region. People are exposed to toxics compounds in several ways:

* By breathing the air which affects both workers in the plant and people who live nearby;
* By eating locally produced foods or water that have been contaminated by air pollutants from the incinerator; and
* By eating fish or wildlife that have been contaminated by the air emissions.

Dioxin is a highly toxic compound which may cause cancer and neurological damage, and disrupt reproductive systems, thyroid systems, respiratory systems etc.

Financial Impacts
All over the developed world, almost half the investment is put in control systems to reduce toxic emissions such as mercury, cadmium, lead, dioxins, furans, volatile organic compounds etc. For example a 2000 MT per day incinerator can cost upwards of $500 million in Europe, half of the cost being put into emission control. Another problem arises in the case of developing countries because the average calorific value garbage in such countries is about 800 cal / kg. For combustion technologies to succeed they would need about 2000 to 3000 cal / kg, other wise auxiliary fuel has to be added. This makes the process more uneconomical and polluting than it already is.

Most of the size and expense of the incinerator is dedicated to the pollution control equipment. The first component of the pollution control equipment is the stage at which ammonia is injected into the gases produced from the burning process which assists in the removal of NOx. The removal of mercury is achieved by the injection of activated carbon. Lime is then injected in the dry scrubber stage whereby the acid gases are removed. Further, most incinerators have a bag-house or electrostatic precipitator to facilitate the capture of particulate and toxics. Thus, it can be realized that the cost of the pollution control system over-rides the cost of the incinerator by a huge margin.

Incineration experts generally state that to have an economically viable operation, it is required to have an incinerator that burns at least 1000 tonnes of garbage each day. The cost to build such a facility is approximately $100 million. Operating costs to maintain the equipment, especially the pollution control equipment is also high.

It is dangerous to bury fly ash in a regular municipal landfill. A special hazardous waste landfill is required which is almost ten times costlier than a municipal landfill. Therefore, the cost of municipal waste incineration shoots up due to the requirement of a special landfill for fly ash disposal.

Conclusions
The adoption of alternative cleaner methods for the disposal of municipal garbage is necessary. According to the United Nations Environment Programme (UNEP), incinerators are the leading source of dioxin into the global environment. The EPA, in a recent study, identified dioxins as the cause of many cancers, the worst component being TCDD (also known as Agent Orange).

The need for low-cost solutions presents significant difficulties, but it is not an impossible task. The ideal resource management strategy for MSW is to avoid its generation in the first place. In 1993, a Royal Commission on Environmental Pollution in England issued a four-stage decision procedure of which the first two stages state:

* Wherever possible, avoid creating wastes,
* Where wastes are unavoidable, recycle them if possible.

This implies changing production and consumption patterns to eliminate the use of disposable, non-reusable, non-returnable products and packaging.

An integrated solid waste management (ISWM) is essential to establish a waste hierarchy to identify the key elements. The general hierarchy should be comprised of the following order:

1. Reduce
2. Reuse
3. Recycle
4. Waste minimization and recovery of energy from waste by composting, anaerobic digestion, incineration etc.
5. Landfilling

The cost of building and operating incinerators or providing special landfill sites is enormous. If substantial parts of these funds were to be diverted towards waste minimisation and encouraging recycling, the need for waste disposal could be enormously reduced, apart from reducing the dangers which arise from both incineration and landfill. It is essential to explore the potential of environment-friendly technologies, like anaerobic digestion (AD), for the treatment of municipal waste because it holds the promise to address two highly important environmental concerns – waste management and renewable energy.

Written by Salman Zafar, Renewable Energy Expert.

What do you think?

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  • howard hager

    This paragraph is very misleading concerning today’s WTE plants. The EPA has srtict rules and most countries do as well. Here in the USA the EPA is very active and monitors all WTE sites. Covanta energy has a track record of being 90-99% below EPA emmission standards. The go to great lengths in their design to make sur ethe emmissions are not harmful. This isn’t incineration as was the case years ago. This is reduction of waste under controlled heat with out gasses being subjected to emission controls that are automated and strict. This has been the case for over the past many years for their plants. They have been awarded environmental awards from the EPA and others because of the safe emmisiions. It is a disservice to lump them with the incineration plants of old. One can verify this by looking at the EPA and their web sites or visiting a plant. It makes safe renewable energy from the home grown local renewable fuel… trash. Oh also they do recycling at these plants. Metals are extracted and the resultant ash (90% reduction from the trash put into the system) has a recycle use also. The plants input sources can be after recycling companies pull addition materials out like cardboard and plastics. This energy production is safe, clean, helps keep landfills from filling up and does recycling form local fuel material(trash). So what elese does this kind of energy manufacturing not coal or gas or oil?

  • Billy Bob

    I disagree with what your saying howard…You’ve given no true stats with your response and there has not been a magic discovery of a method to burn for energy without emissions. Even if they have cut back heavily on emissions they are still emitting and they have most likely only solved the problem for the big emissions what about volatile organic compounds that are left over that destroy the environment and just because the ash can be reused doesn’t secure that it will be. Reusing ash could be more expensive than it’s worth to the programs

  • Don

    There is public opposition of energy from waste facilities. When I was first introduced to this idea my first thought was billowing black toxic smoke caused by burning garbage. As I have become more educated over the years I have learned that it is much more regulated than other industry emitters. Most likely driven from public opposition. In an idealistic world recycling is the answer. But in a realistic world recycling recycling and energy from waste are both going to play a role in waste management.

  • Clinton

    I am very interested in the Waste-to-Energy industry. Could any of you point me in a direction where I could get some more facts and some of the concerns people have about WTE plants? Thanks

  • Salman

    Thanks for your comment, Clinton. You may write to me at salman.alg@gmail.com to know more about the WTE industry.

  • sidney mehlschmidt

    The city of Vienna in Austria has a large incinerator right in town which generates steam heat for the nearby General Hospital, as well as numerous other buildings around town. The exterior was designed by artist Fritz Hundertwasser and is a pretty wild sight to behold. They also produce electricity in the process. I’m under the impression that the Europeans are much more sensitive to environmental pollution than we are, so I have to assume that their restrictions on air pollution are pretty strict. Metals are removed from the ash after incineration and recycled. The added benefit, of course, is a severely reduced need for landfill space. Since we generate so much more garbage per person in this country, it’s beyond me that this technology hasn’t caught on over here.

  • Glenn

    What are the current alternatives to waste to energy plants similar to that run by Covanta in Rochester, MA? Is technology changing and is the cost of disposing of waste likely to be reduced substantially from the costs charged to municipalities currently in the Southeastern Massacusetts area?

  • Joseph

    Billy Bob the Enviro guy… pull the data at the EPA. Talk to Wheelabrator (a WM company), go visit a WTE. This is not a place to post 50 pages of data for you to review. Still emitting? LOL, you emitting everytime you speak there Billy Bobby. I can have a bonfire on the farm and but more stuff in the are than a WTE. Bill, what is done with medical waste? Say Chemo? 1500+ F to get a kill on that stuff. You want PIMW buried in your local landfill without being cooked? I don’t. Don’t spin the autoclave thing either, there is no kill involved. Oh the ash, can be used. In India they use it in concrete, can’t get enough of it. So Billy Bob the Uniformed Enviro, come into the light! Go talk to some folks at SWANA. The cost numbers of feeding the WTE in tons, are depending on size of operation desired, thus so the cost of construction impacted. That would be the prefered numbers, it can be done on a smaller scale. 10 times more costly to build a Special Waste Landfill? Where did you get that number? Who’s building that thing; the government? Wow, $100m usd to build a Fac, again, a govt funded fac. Must be like the Big Dig Project in Boston. This is clearly a left leaning article. Without much real world working experience. Nor formal economic education. Go work in the business for a while before writing an article for the Sierra Club.

  • Waterlilly

    What is the difference between a coal fired power plant and a Waste To Energy (WTE) plant? Let’s take a quick look at funding. The coal fired power plants are the most well funded energy lobby in the US. WTE technologies receive less than 1% of that funding, in comparison. Coal requires massive mining operations obliterating entire mountain ranges to granite shards. Garbage – a guaranteed resource, to last as long as humanity does – is the fuel of WTE. Landfilling generates methane. Methane = >20 times worse green house gas than CO2.

    Instead of landfilling the garbage, burning it reduces green house gas emissions, boosts recycling (because those metals are worth a pretty penny), and eliminates the NIMBY syndrome of future landfill sites. But as long as the coal lobby has the upper hand they will do their best to conceal the fact that coal fired power plants account for >80% of the mercury being released into the environment, that account for the high concentrations of mercury in great lake’s fish, and polar marine life.

    In China, 1 new coal fired power plant is opened every five days. When I was in Shanghai, ships sped furiously upriver to provide the hungry power plants with an abundance of coal. Sometimes you had 15 boats one after the other, like rail cars crowding the river. As long as the status quo (energy barons benefiting from the sale of coal and petrol) has it’s hand in the game, there will be no room made for true alternatives using free resources and comparatively benign technologies (WTE).

    As Machiavelli rightfully stated: “It must be considered that there is nothing more difficult to carry out, nor more doubtful of success, nor more dangerous to handle, than to initiate a new order of things. For the reformer has enemies in all those who profit by the old order, and only lukewarm defenders in all those who would profit by the new order, this lukewarmness arising partly from fear of their adversaries, who have the laws in their favour; and partly from the incredulity of mankind, who do not truly believe in anything new until they have had actual experience of it. Thus it arises that on every opportunity for attacking the reformer, his opponents do so with the zeal of partisans, the others only defend him half-heartedly, so that between them he runs great danger.”

  • Pablo Colman

    Dear Sirs, I have been following the discussion initiated by Mr. Salman Safar, and I would like to know your opinions regarding the technology that I am going to describe below, best regards and thanks a lot.

    The Waste Gasification / Thermal Oxidation Plant (WG / TO) is a two-stage waste combustion process that converts combustible organic matter from its existing solid, sludge or liquid state into a gas under an oxygen depleted environment (also known as “oxidation”). The resulting gas product is then well mixed with ambient air before being burnt off (flared) in a secondary gas-processing unit.

    The WG / TO is comprised of three basic components: a Primary Gasification Cell, a Secondary Gas Processor, and a computerized Process Logic Controller. Combustible waste material is placed into the primary gasification cell through the load access door. In some facilities this can be done via a loading conveyor. The proposed design is to have collection vehicles dump their Municipal Solid Waste (MSW) load directly into the primary oxidation cell.

    The Primary Cell can be either a batch or continuous feed processor. Based on our experience, batch processing provides the most efficient and cost effective strategy for the waste management solution. In the case of batch processing once the cell has received that days collected waste, the door is closed and the process is initiated. The cell does not have to be full for the system to be activated.

    An operator is responsible for supervising the loading of waste material, and initiating the process start-up. A computer keystroke (or optional manual button and lever control) which pre-heats the secondary gas-processing unit accomplishes this start-up. Once that unit reaches its pre-set temperature, the primary gasification cell heater is activated, and the process begins. 8 to 12 hours later, the organic wastes in the primary cell will have been converted to a gas, and the cycle will generally be complete.

    With the help of the Process Logic Computer (PLC) , the operator can evaluate the end of the gasification cycle by observing the change in oxygen content of the stack gas in the primary cell, and a predictable deadline in the primary cell temperature. Once these final conditions are reached, the PLC will indicate to the operator that the cycle is finished, and the system will move to its “cool down” mode. In another 4-6 hours, the system may be re-loaded, and another process started, with or without the removal of the preceding load’s ash material.

    Residual materials (bottles, cans, ash and misc.) need only to be removed periodically. The composition of MSW consists mainly of organic and combustible waste. Glass and metals are easily extracted in our plant design as it includes equipment that will assist in the process and cut down on labor man-hours. Ash removal is either an automated or manual process. In automated unloading, the base of the primary gasification cell contains a ductile iron furnace floor conveyor that evacuates material remaining in the base of the unit through a side access door. This dry waste material empties into a storage bin, which can be removed to another location for recycling.

  • Salman

    Hi Pablo,

    Thanks for sharing this information.The technology looks interesting. I would like to know more about the capacity and cost of your system. Kindly write to me at bioenergyconsult [AT] gmail.com

    Best wishes
    Salman

  • Max

    Hi Pablo and Salman,….

    as we following and study all serious info about WTE and latest CHP technologies, please send me also the details of your mentioned Waste Gasification / Thermal Oxidation Plant (WG / TO) system. Can you inform us also where this technology was running ?

    Thanks, Max

  • demostic

    Hi salman, thank you for your expository write up. Can we like Clitton, get in touch with you through your email? All hands must be on deck to use alternative waste to energy which obviously help to reduce emissions.

  • Kenton

    Is there a low-cost system that will work in a third world country? Waste is a huge issue here, with tons of garbage each week. One of the largest costs here in the second largest city in this country is the disposal of garbage. If that cost could be turned into energy instead and help keep the country clean it is a win-win.

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