The big picture

Human activities produce a diverse range of waste from an equally diverse range of activities. Waste may include food, paper, plastics, textiles, construction material, batteries, street sweepings, hazardous wastes etc. The waste comes from residential areas, industry, commerce, construction sites, manufacturing and agriculture. Wherever it comes from or whatever it is, it is increasing in volume.

All types of waste are a problem but the focus here is domestic waste – stuff that we throw out in our everyday lives. Figure 1 shows the changes in the amount of domestic waste generated in the UK between 1984 and 2002.

Figure 1. Domestic waste generation in the UK 1984 - 2002.

Figures were taken from the UK government Department for the Environment, Food and Rural Affairs (DEFRA).

The statistics are the same in many MEDC’s Figure 2 shows a similar trend for Australia. An encouraging drop in the total amount of waste generate annually between 1993 and 1994 was followed closely by a consistent increase.

Figure 2. Domestic waste generation in Australia 1993 - 2002.

Consider this - in the time span of the graphs our recycling technology has improved and the proportion of waste that is recycled has increased consistently in both countries. Why then is the total amount of waste that has to be managed increased? The answer is not simple. Population increase accounts for some of that increase. However, there are additional factors that make matters worse e.g. consumerism, more disposable income to buy what we want and not just what we need.

Our waste management systems are improving. As the graphs show more people recycle more products. In addition to that composting is being introduced to deal with biodegradable waste. The problem now is the increase in the amount of hazardous and non-biodegradable waste. There has been a marked increase in the use of electronics in modern society and that means the generation of e-waste. This type of waste is toxic and requires specialised waste management in order to avoid problems for the environment.

Managing the waste stream from production through collection, handling, storing, separation and disposal is now a big business. However, unless we can get it right and reduce the volume of waste the sustainability of our linear systems is under question.

Solid domestic waste (SDW)

SDW is more commonly called trash or garbage in the US and rubbish in the UK. It is the everyday items that we discard; the volume and composition of which has changed over time.

In the past human population densities and resource exploitation were low and the amount of waste generated was insignificant. Common waste products in the past would have been ashes and biodegradable human waste. At low volume the local environment would have absorbed all of this. There would have been minimal food waste and tools were passed down from generation to generation.

Figure 1. Low population density = low waste generation

A major change in this situation occurred with the onset of industrialization and urbanization. For example, in the UK the growing urban population had no formal waste disposal system. Hence, there was a rapid build up of waste, the quality of city living deteriorated and the environment quickly became unsanitary. By the mid nineteenth century public health issue in London were chronic and cholera outbreaks common. Such outbreaks spurred public health debates and in 1846 the Nuisance Removal and Disease Prevention Act kicked started regulated waste management in London. Thereafter waste management evolved slowly:

• In 1874 the first incinerators were introduced as a waste management strategy.
• In 1875 the Public Health Act introduced the concept of a bin to hold household waste.
• Waste collection vehicle started as open horse-drawn trucks that spread odor and disease everywhere they went.
• During the 1920s closed trucks were introduced.
• Then in 1938 the modern hydraulic compactors were introduced.

So as the population increased the amount of waste generation also increased and the management of it developed.

Waste management is now big business and here we consider the four major waste disposal methods:

1. Landfills
2. Incineration
3. Recycling
4. Composting

Types of SDW

The types of domestic waste are now far more varied than they have been historically (Table 1). The relative proportions of these types of materials are shown in Figure 2.

* data was taken from Australian Bureau of Statistics

Figure 2. Relative proportions of SDW in Australia.

Linear vs. circular

This very brief video explains the difference between a linear and a circular economy. That difference is largely the cause of the current waste disposal management problem.

Our economy is a linear economy as described in the Story of Stuff. That means we dig things out of the ground, make products that last a brief period of time and then throw them into landfills (in the ground). This is a waste of resources, energy and money; it is also very damaging to the environment. It is this linear economy that is largely responsible for many of the waste management problems.

The solution to this problem is a circular economy. A circular economy is restorative - goods are designed so that material re-enters the system naturally as part of the overall design process. We do this partially with recycling. The problem with recycling is that the materials in them were not originally intended to be reused so it is not that efficient (but it does help). In a circular economy there are two types of material flows:

• Biological nutrients – these are used and then can re-enter the biosphere harmlessly. If these nutrients are managed correctly their use is sustainable.
• Technical nutrients – circulate without re-entering the biosphere. That is they are reused again and again.

Figure 3. Linear vs. circular economy.

Figure 3 shows the linear economy at its worst. Natural resources go in one end, they are processed using finite energy resources such as coal or oil and then they are dumped. In a circular economy the materials keep going around and around, just like they do in the matter cycles of ecosystems. All of this is done using renewable energy.

Theory of Knowledge

The linear economy and the circular economy are two models. One seems intuitively correct - when is it safe to trust intuition as a way of knowing?

Non-biodegradable waste

Apart from the issue with a linear economy, there is an additional problem with waste management and that is the abundance and prevalence of non-biodegradable and toxic waste. Non-biodegradable waste is anything that will not breakdown into simpler components e.g. plastic. Toxic household waste tends to contain batteries and e-waste.

Plastic plays a very important role in our lives these days. Plastic is in almost everything we use – shopping bags, drinks bottles, packaging, toys, furniture – just look around you. According to the EPA (Environmental Protection Agency) in 2013 plastic made up 13% of the SDW in the States, from 1% in 1960. Much, but not all of it can be recycled. Plastic is made from crude oil, a non renewable, finite resource – so recycling is pretty important. If you want to learn more about plastic pollution go to Coastal Care.

Figure 4. Where does all the plastic go?

Batteries are also very common in our everyday lives. Make a list of everything that you use that needs batteries – don’t forget all you favourite electrical gadgets. Technology is helping as many batteries are now rechargeable – all the ones in laptops, tablets and mobile phones for a start. Also many removable batteries are now rechargeable. The problem is that at the end of their lives they must be disposed of properly as they contain toxic components including heavy metals (mercury), acid and other dangerous substances that are harmful to the environment.

E-waste (electronic waste) is probably the fastest growing SDW. E-waste includes anything electrical or electronic devices. Again take a look around you and think about what this category includes. This is another waste type that can be recycled, and reused, reconditioned and re-sold. However, once it reaches the end of its life e-waste has many toxic components e.g. lead, cadmium, and brominated flame-retardants.

Figure 5. Projected global e-waste growth by volume.

International-mindedness

Explain the differences in the amounts and types of waste generated in different countries.

Dealing with SDW: Landfills

This video explains what happens at landfill sites.

Landfill is the oldest and probably the most common method of organized waste disposal in many countries of the world. A landfill site may also be referred to as a dump or tip. In its simplest form it is a hole in the ground where waste materials are buried. Modern landfill sites are no longer a simple hole in the ground – environmental protection agencies are ensuring higher standards of protection for surrounding areas.

In non-hazardous landfill sites certain specifications must be met:

1. The landfill must be lined either with clay or a synthetic flexible membrane (or both!). The liner is necessary to avoid leachate (water contaminated with wastes) leaking into the surrounding environment and groundwater.
2. The dump site should be as small as possible as it is much easier to monitor the site.
3. The waste is compacted regularly to reduce volume.
4. Waste is covered daily with soil. This reduces the lighter waste being wind blown around. It contains the smell and reduces the vermin problem.

Figure 1. Landfill site.

In addition to this a strict regime is followed at all times the landfill is in use. When vehicles arrive they are weighed and inspected. This is to keep records of the amount of waste that is processed and ensure that toxic/unacceptable waste does not enter the site.

The waste collection vehicles then drive along an existing road to the tipping face where they dump their load.Bulldozers and compactors then spread and compact the waste before the next load is dropped. The vehicles then pass through a wheel cleaning area in order to remove any waste that may be stuck in the wheels.

The compacted waste at the workface is covered with one of the following - soil, chipped wood, spray-on foam products, chemical bio-solids and temporary blankets. The blankets are placed on at night and then removed before tipping starts the next day. The life span of a landfill will depend on:

• The compressibility of the waste.
• The thickness of the layers.
• How often the waste is compacted.
• The amount of waste added each day.

If you want more details about landfill sites visit this site.

International-mindedness

Landfills provide much employment but in very different ways in different countries.

Waste to energy from landfill gas

This videos gives a brief explanation of one of the ways in which waste can be turned to energy.

One way that landfill sites can become beneficial is in waste to energy schemes. Landfill produces significant amounts of gas (mostly methane) during the decomposition and break down of the waste. These gases are hazardous and can cause explosions and fires so in most MEDCs it is a requirement that they are collected and disposed of – usually by flares (burning off).

Landfill gases (LFGs) must be burnt off so scientists devised a solution - collect the gases and use them to produce electricity. Gas collection is achieved through a series of interconnected wells drilled into the landfill. The landfil gas is then de-watered and used in engines/gas turbines to generate electricity.

This is not a major part of your learning but if you are interested there are many websites that give more detail about these waste to energy schemes. The Viridor website gives information about this and many other waste management options.

Examiner Tip

Make sure you can:

1. Evaluate landfill as a waste management strategy.
2. Compare different strategies.
3. Discuss why landfill may be the strategy of choice for some countries and not others.
4. Explain where landfill fits in the pollution management models in Figure 1 in the section "Dealing with waste pollution".

(You will not be able to tackle 2-4 until you have read the next sections.)

Dealing with SDW: Incineration

This video gives a very brief explanation of incineration.

Incineration is a waste treatment process that involves the combustion of waste. Initially incineration was simply burning trash in a hole in the ground, or as a pile on the ground. The process is less simple now but the basics are the same – the waste material is combusted and converted into:

• Ash: this is what is left after the burn.
• Flue gas: this may contain particulate matter (ash) and pollutants so it is scrubbed before entering the atmosphere.
• Heat: which may be used to generate electricity e.g. waste to energy incinerators.

Figure 1. Waste incinerator.

Theory of Knowledge

Our knowledge of waste disposal is changing all the time. How can we know for sure which method of waste disposal is the best?

Evaluation of incineration

There are many advantages and disadvantages to incineration.

Incineration developed as a technology when landfills availability became limited. Whether or not incineration is used will depend on many factors – not least of which, is the available alternatives. In areas where landfill space has been used up they are becoming more popular. However, incineration has a bad press and as alternatives have become more viable incineration has become less popular.

International-mindedness

The case study gives a small selection of counties that use incineration as a method of SDW disposal. Consider why different countries do or do not opt for incineration.

Examiner Tip

Make sure you can:

1. Evaluate incinerators as a waste management strategy.
2. Compare different waste management strategies.
3. Discuss why incinerators may be the strategy of choice for some countries and not others.
4. Explain where incinerators fits in the pollution management models in section 1.5.2, Figure 3.

(You will not be able to tackle 2-4 until you have read the all the sections in this subtopic.)

Dealing with SDW: Recycling

Recycling is actually only part of a mantra and just one way of dealing with SDW. The full mantra is reduce, reuse, recycle or the three R’s. With the increasing volume of SDW many countries are now promoting the three R’s in order to combat that increase. The most effective way is to go for management strategies in that order:

• Reduce the amount of waste being produced in the first place, that is alter the human activity that produces the waste.
• Reuse an item multiple times, either for the original purpose or for some other purpose.
• Recycle the material of the object by transforming it into the raw material for a new object.

Theory of Knowledge

Advertising and educational campaigns have made us believe that reduce, reuse, recycle is the way to go for SDW disposal. Which ways of knowing are most powerful in persuading us of these "facts"?

Reduce

This is the most important strategy, simply because by reducing the amount of waste produced you reduce the amount you have to reuse or recycle. The first place to start with waste reduction is too look at the design, manufacture and packaging of products. If the reduction starts in the design phase there is less use of raw materials, lower energy consumption and less waste being produced. This has obvious attractions for businesses.

Aluminum cans are one of the best examples of looking at the design of a product in order to reduce the waste. Aluminum cans now use only 60% of the raw material used 20 years ago. A simple look at how much aluminum was needed to do the job and you have reduced your waste. Costs go down for the manufacturers, fewer raw materials are used and less waste is produced.

Disposable nappies (diapers) are another good example. With improvements in technology came the development of a super-absorbent polymer (gel) that can absorb 800 times its weight in water (or urine). This decreased the amount of paper pulp used and tat meant less waste going to the landfills/incinerators. BUT - stop and think this one through. What is that gel made from? It is a petroleum based chemical so we have replaced a renewable resource (wood) with a non-renewable one (petroleum). This then is a mixed blessing – the amount of waste is reduced but maybe not in a sustainable way.

Many companies have also looked at the way they package items. If they reduce the amount of packaging they use they reduce their costs and if we are lucky some of the savings are passed on to the consumers. Check out this article by the New York Times. The packaging associated with many mobile phones, tablets and laptops has been steadily decreasing too.

Figure 1. Packaging.

Reuse

This aspect of the three R’s can be quite diverse because items can be reused in so many ways. Some products can be used for the same purpose over and over again; others can be used for the primary purpose first time and then something else next time round.

In many countries glass soda and beer bottles are reused repeatedly. The customer pays a deposit on the bottle and when the bottle is returned the deposit is retrieved. The bottles can then be sent back to the bottling factory to be cleaned and re-filled. Such schemes do have drawbacks – collection and cleaning of the original item; but they definitely reduce the amount of waste entering landfill sites.

There are many ways that old items can be reused in different and unique ways. Jars and pots can be used as stationary holders, old tyres make great swings and in Tanzania they are made into flip-flops, paper waste can be used as a packing material and paper that has print/writing on one side can be reused on the other side.

There is also a great way to reuse old books, they can be donated to libraries, schools or book clubs. In fact it is better not to buy books in the first place just borrow them from the library. Or you can use e-books instead, though that would be the reduce in the three R’s. A single e-reader or similar device can hold hundreds of books. Of course there is a down side to e-books - you have to have a device to read them on and the ability to charge that device.

Figure 2. Reuse of items for alternative purposes.

Recycle

This is the last stage of the three R’s if you can’t reduce or reuse please recycle. To recycle something the original product is transformed into a new raw material that can be used for another product. There are a number of materials that are easily recycled – glass, paper, metal textiles, electronics and some plastics.

Recycling has the following benefits:

• Prevents the loss of useful raw materials.
• Reduces the consumption of new raw materials.
• Reduces energy usage in some areas (though collection and processing does use energy).
• Reduces pollution at the extraction phase of the process - getting the raw materials out of the ground.
• Lowers the release of greenhouse gases.

Starting up a recycle programme is difficult. If there are no industries that will process the recycled material then there is no point setting up a recycle programme but if there is no recycle provision then the industries will not develop. Recycling is usually started by government initiatives that get over these initial problems. Offering tax incentives to companies to set up recycling industries and running education programmes to encourage the population to recycle. Once the initial problem has been overcome there is a variety of ways that recycling can be deployed.

Curbside recycling is common practice in many countries. Residential districts have a set day on which to place their recyclables out for collection. Different agencies will collect different material on particular days. Once the population is used to the system it is a very efficient way to separate the waste and it is easy for the residents. The problem is that it means the waste collection trucks are operational most days and that increases fossil fuel consumption.

Alternatively there are recycling centers in frequently used public areas – parks, shopping centers and major supermarkets. Several large bins are placed in these areas with clear labeling for different items. This makes it easy for collection but more of a burden is placed on the public to bring the recyclables to the centers. They are also prone to vandalism.

Figure 3. Recycling centers.

Examiner Tip

Check out the recycling programmes in your local area - this will give you an easy to remember case study. If there is nothing in your local area find one that interests you.

How can we operate the three R's and will it work?

Table 1 gives a few possible ways to implement the three R's along with an evaluation of their likely effectiveness. You will notice that it is hard to separate out the reduce from the reuse and the recycle. That does not matter - it all goes to help solve the problem of the volume of SDW.

These are just a few suggestions for the three R's – do your own research and see if you can find more ways to incorporate them in your life – think about their effectiveness for you and others.

International-mindedness

Different countries use very different recycling schemes. Discuss the differences.

Examiner Tip

Make sure you can:

1. Evaluate the three R's as waste management strategies.
2. Compare different waste management strategies.
3. Discuss why the three R's may be the strategy of choice for some countries and not others.
4. Explain where the three R's fits in the pollution management models in section 1.5.2, Figure 3.

(You will not be able to tackle 2-4 until you have read the all the sections in this subtopic.)

Dealing with SDW: Composting

Composting has been practiced since early Roman times (AD 23 – 79) so it is not exactly new. In early times composting simply meant piling up organic material and leaving it until the next growing season. By then the material was decomposed enough to be ready to mix into the soil where it continued to breakdown and supply nutrients to the plants. This was a simple method that worked effectively when there were no time or space issues. Although nutrients are lost whenever it rains and there is a risk of insects and other vermin being present. Composting did lose popularity for a while but in the UK it is becoming more popular again. Local authorities collect food and other biodegradable waste though kerbside collection, compost it and sell it.

Theory of Knowledge

Composting has been used as a method of SDW disposal for centuries. Compare the role of indigenous and scientific knowledge in developing the best strategies for composting.

Figure 1. Organic matter left out to decompose.

Composting was partially modernized in the 1920s and went through a variety of changes between then and now. Scientists and other advocates of composting worked in MEDCs and LEDCs in order to promote the use of composting for agricultural purposes. Now it is recognized that it serves other purposes too – reducing the amount of waste that ends up in landfills and incinerators. Modern composting has “come a long way” according to some authorities. It has been tweaked and science has been applied to the process to speed it up. This is achieved by:

• Reducing and standardizing the size of the and composition of the compost.
• Controlling the carbon-to-nitrogen ratio.
• Monitoring and controlling moisture levels.

Composting is still basically the same, except that some modern techniques push the heat up to speed the process and kill pathogens and seeds.

Composting is a very effective waste management strategy because it combines the three R’s. Removing organic material from the waste stream reduces the amount going in to landfills. The decomposed organic matter is reused and recycled as soil fertilizer. Composting is simply using natural decomposition processes as a waste disposal method. It has risen in popularity again with the realisation that soil fertility is suffering under chemical fertilizers and we need environmentally sound methods to deal with our ever-increasing food waste.

This video shows how one company responded to the need to reduce their organic waste volume.

International-mindedness

Consider the role of composting in primitive and modern societies.

Examiner Tip

Make sure you can:

1. Evaluate composting as a waste management strategy.
2. Compare different waste management strategies.
3. Discuss why composting may be the strategy of choice for some countries and not others.
4. Explain where composting fits in the pollution management models in section 1.5.2, Figure 3.

(You will not be able to tackle 2-4 until you have read the all the sections in this subtopic.)

Dealing with the pollution

Solid domestic waste management has four basic strategies, landfill, incineration, the three R’s and composting. These all fit into the pollution management model and the management strategy of choice will be dependent on culture, economics, technology and politics.

Figure 1. Stages of pollution management.

Educate

This is the best level to operate at, as it is lowest cost financially and environmentally. The main aim of the educate strategy is to alter the activity that is producing the pollutant. In this case, the aim would be to reduce the amount of SDW that is produced.

If we consider our four basic strategies the best way to reduce the amount of waste is by employing the three R’s and composting. All these strategies cut down on the amount of waste that is generated thus reduces the SDW management problem. So the question is “why are these strategies used in some places but not others?” It is rare that any one factor operates in isolation so we will consider them together.

Some countries simply have a culture of reduce, reuse, recycle and composting. This would not have always been the case but years of education in most MEDCs has imbedded the mantra deep in the psyche of most people. Not to mention the fact that it is now compulsory in many countries so people do not have the choice. The political climate and an economic penalty is usually enough to persuade people to use recycle schemes.

On the other hand LEDC’s have a very effective informal recycling culture often driven by need. There are whole social groups that live on and make a living off landfill sites e.g. Thailand and the Philippines. In these and many other LEDC's people live on the landfill sites. They sort through the waste to find useful items that they can sell or use for themselves. Although this is not altering the activity that generates the waste it is removing much of the waste from landfills. If you want to see more about this way of life check out Trash by Andy Mulligan.

Figure 2. Whole communities live on landfill sites.

The poorer end of the socioeconomic spectrum is also far more likely to buy items from second hand shops. Plus they are more likely to receive charitable donations of clothes and waste food. Economic pressure means they are less likely to waste food and more likely to reuse things again and again.

Economics, technology and politics work together to influence the choice of SDW management strategy. MEDCs have the money and the technology to put formal recycling schemes in place whereas poorer countries do not. You cannot start recycling if you do not have the technology and companies in place to process the recyclates. Politically, MEDC governments receive a lot of pressure from environmental lobbies and the general public to “do something” about environmental degradation. LEDC governments and their people are more focused on the basics of survival. They are not concerned about what might happen if...(we don’t recycle etc.).

Legislate

If people cannot be persuaded to reduce the problem at the source then the next best option is to control the release of the pollutant through legislation. This is used increasingly in MEDCs and the main factors driving the implementation of the legislation are economic and political.

In Europe the political ban on the use of landfill sites for hazardous waste encouraged the adoption of incineration as a SDW management strategy. This was further encouraged when the generation of electricity in waste to energy schemes attracted tax credits. The UK did not see an increase in incineration until the EU directive imposed taxation on the use of landfill sites pushed up the economic costs of waste disposal in landfill.

Figure 3. European parliament.

Economic incentives are used to encourage the use of the three R’s. This is often backed by political desire to sway the “Green” vote – that is win the vote of the environmentalists. Some authorities will collect domestic recylates for free but will charge a fee for anything that is not recycled, a financial penalty usually works to encourage people to comply!

If a country is considering waste to energy programmes through incineration then the technology and money must be in place to support that. Waste to energy programmes are a costly undertaking and many LEDC's do not have the set up costs required, even though it would create savings in the long run. Even with backing from MEDCs the poorer countries struggle to run the waste to energy plants safely due to lack of expertise.

Remediate

This is the last stage of the pollution management model and if this strategy has to be implemented it means everything else has failed to address historic mistakes. This signifies environmental damage and high financial costs. With reference to SDW the remediate comes in the form of reclaiming landfill, waste to energy programmes and implementing initiatives to clean up an environment e.g. removal of the plastic from the Great Pacific Garbage Patch.

Reclaiming landfill is necessary due to the large amount of SDW that has been generated in many MEDCs over the past decades. Landfill was the preferred waste management strategy long before there was the realization that it would one day cause a problem. The decision to reclaim landfill sites is mainly economic and political, but it is dependent on what sort of material has been dumped there and its location. If the landfill has been used for non-toxic waste, has been carefully managed and the economics are favorable then the site can be reclaimed relatively easily. The land may be used for recreational purposes – replanting trees and returning the area to a natural state. Others are very popular due to locations close to town and a good price e.g. superstores have been built on some old landfills. It is a long and very costly process, but one that gains political favour.

Waste to energy programmes were discussed under legislation, as it is political and economic pressure that is driving people towards incineration and waste to energy projects. In some cases incinerators are set up at old landfill sites and the long process of burning the old landfill material begins. As discussed before this requires money, appropriate technology and expertise – something lacking in many countries.

The last resort is to clean up the mess. This can be very expensive and very time consuming. It is also an example of a serious deterioration in successful management strategies. The Great Pacific Garbage Patch (GPGP) is a testament to a failure of management strategies on all levels. GPGP is a testament to a failure of management strategies on all levels.

Theory of Knowledge

To what extent does the use of emotive language effect how we judge an issue such as theGPGP.