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Environmental impacts of waste management

Waste management

The EU has a pyramid structure for waste management. This is known as the waste management hierarchy which is a priority list for disposal of waste in the following order - reduce and reuse, compost, recycle, waste to energy incineration, landfill. The methods at the top are the preferred methods and the ones at the bottom the least preferred. They also set clear targets over waste management and countries can be fined if they fail to meet those targets. This is a common method for many HICs. The key targets are to reduce the amount of waste in the first place that way there is less to deal with afterwards. Current campaigns against the use of single use plastics are examples of this, as are the use of a “bag for life”

Methods of waste disposal

In High Income countries much waste is dealt with by either landfilling it or by incinerating it (often with some form of energy recovery). These methods are coming under increasing attack because they can be environmentally damaging and are considered unsustainable. In many LICs the major issue is with unregulated waste disposal, waste that is dumped and not controlled or regulated by the city authorities. This poses huge human health risks.

Incineration

Incineration is a waste treatment process that involves the combustion of organic substances contained in waste materials. It can reduce the volume of waste by up to 90% leaving only ash that still needs to be disposed of. The environmental impacts of incineration are that it releases a wide variety of pollutants (e.g. particulate matter, metals, acid gases, oxides of nitrogen, and sulphur, toxic substances) depending on the composition of the waste, which leads to health deterioration and environmental degradation. It was used in the past in many countries but many HICs are shifting to energy recovery or energy from waste

Energy recovery

 

Energy from waste or energy recovery is basically using heat derived from incinerators to heat buildings and/or generate electricity via steam produced by burning waste to heat water. It involves burning waste at very high temperatures to eventually reduce the amount of waste and then produce electricity. Municipal Waste is unloaded from collection trucks and placed in a rubbish storage bunker. An overhead crane is used to sort the waste and then lift it into a combustion chamber to be burned. The heat released from burning is used to convert water to steam. The steam is then sent to a turbine generator to produce electricity. The remaining ash is collected and taken to a landfill. Particulates are captured by a high-efficiency bag house (a filtering system). It has numerous environmental advantages over simple incineration –

  1. It disposes of solid, liquid and gaseous waste.
  2. It is a practical method of disposing of certain hazardous waste materials (such as biological medical waste).
  3. Ash residue from the furnace can be processed for removal of recyclable scrap metals.
  4. Filters can remove many of the emissions
  5. It reduces the amount of waste going into landfill.

However, the incineration process produces ash which still needs to be disposed of. This ash can be contaminated with toxins. These need special landfill for disposal. Emissions from incinerators can include heavy metals, dioxins and furans, which may be present in the waste gases, water or ash. The combustion of plastics, like polyvinyl chloride (PVC) gives rise to these highly toxic pollutants. Waste incineration systems produce a wide variety of pollutants which are bad for human health. 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.

Newcastle_Waste_Disposal

Landfill

Landfill is the disposal of refuse and other waste material by burying it and covering it over with soil. They are essentially hollows in the ground where rubbish is dumped. Historically no real strategies were put into place to prevent environmental damage were minimal or non-existent. Modern landfills have linings of plastic or compacted clay to prevent leachate (a mixture of materials from the waste in the landfill and rainwater) from running out of the landfill. This leachate is collected in pipes and transferred to leachate ponds where it can be treated to minimise damage to the environment. Gases such as Methane that are produced as the waste decomposes are also collected and reused as fuel. Successive layers of waste and earth are laid down, and landfills often have netting surrounding them to prevent windblown waste escaping. Many of the new landfills are built as lined facility with membranes or soil used to stop materials leaking, and with leachate collection and treatment on-site. The landfill is designed and built to store waste; this is thought to be a safe containment of our waste.

landfill

Environmentally, Methane gas can be collected at a number of waste landfills and some landfills have diesel/gas blended fuel fired electrical generation stations built on them. This gives electricity from waste materials which are free (except for collection etc.). Closed landfill sites can be recovered for other uses such as housing, golf courses etc. However, many older landfills that are in use are unlined. These landfills and other closed landfills are an environmental threat. This is because they contain hazardous materials and wastes, such as lead from batteries, domestic chemicals (e.g. bleach bottles), mercury from light bulbs, and heavy metals from electronic items. Rainwater can wash these chemicals into aquifers and into our drinking water as LEACHATES. Landfills are often constructed in low lying areas and cover large areas. They attract vermin such as birds and rats. These can be controlled with birds of prey. A final issue is that space for landfills is running out.

A similar type of waste disposal is Submergence. This is dumping waste in water bodies such as the sea, and is banned by international convention. However, it still occurs and this waste could spread across the oceans, be ingested by marine life and plastics can remain in the system for a very long time.

Recycling and recovery

Recycling is nothing new and can take many forms. Within our homes we take old materials and transform them into other items. At council level or at national scale recycling becomes more important. Large scale recycling involves used products being collected, converted back into raw materials and remade into new consumer products. These recycling plants are often very high tech, with magnets separating metals, hand recycling of other products and vents used to separate paper. Recyclable materials include metals such as aluminum cans, paper, plastic containers, cardboard and wood are all commonly recycled often through municipal programs encouraging bulk household collections. When a recycled good i¬s cheaper or weaker than the original product, it's known as down-cycling (or downstream recycling). In some cases, goods can be up-cycled or made into something more valuable than the original product. Recycling can lower costs for industry as there are lower manufacturing costs for products made from recycled rather than virgin materials. Councils and urban areas are often interested in total diversion rates - the amount of material that is recycled and/or composted instead of going into a landfill.

There are several environmental impacts of Recycling and recovery

1. It saves mining and producing new resources,

2. It does require energy in many of the processes and uses water, but not as much as creating new products from raw materials

3. There is inherent value in conserving our natural resources.

4. It is less wasteful, as products are given extra life and there is less need to extract new raw materials.

5. Recycling also raises awareness of how much waste we generate, and therefore makes consumers put pressure on manufacturers to reduce packaging.

6. Some items can’t be down cycled forever, for example, after being recycled a few times, paper is no longer usable.

7. Recycling requires energy and chemicals to recover the waste. It would be better to use waste reduction - the purchase or production of materials and packaging that can be recycled or composted.

Global waste trade and electronic waste

Some items rich countries don’t wish to recycle, such as dangerous batteries or electronic equipment, often end up in poorer countries for processing. This is known as the global waste trade and includes electronic waste. The international trade of waste occurs between countries for further treatment, disposal, or recycling. Toxic or hazardous wastes are often exported from developed countries to developing countries, also known as countries of the Global South. Electronic waste is discarded electrical or electronic devices. Used electronics which are destined for reuse, resale, salvage, recycling, or disposal are also considered e-waste. The disposal of this waste is hazardous and can damage the environment, so unfortunately often waste from HICs ends up for processing in LICs. Guiyu in China is thought to be the largest electronic waste (e-waste) site in the world. In 2005, there were 60,000 e-waste workers in the city who processed the more than 100 truckloads that were transported to the 52-square-kilometre area every day. The Nickname of Guiyu is the "Electronic graveyard of the world" due to the constant movement into and processing of e-wastes in the area leading to the harmful and toxic environment and living conditions, coupled with inadequate facilities.1 & 2

NEXT TOPIC - Comparison of Incineration and Landfill

1 - Wikipedia, Electonic waste in Guiyu. Accessed 12/1/2020 at https://en.wikipedia.org/wiki/Electronic_waste_in_Guiyu

2 - Seattle times – no longer available. Accessed at - http://old.seattletimes.com/html/nationworld/2002920133_ewaste09.html

 

Written by Rob Gamesby April 2020

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