The issue of excessive consumption and the subject of domestic and industrial refuse

Background information

elieve it or not, the problem of domestic and industrial refuse disposal, together with water use, is one of then most pressing problems that humankind faces today.
Why waste disposal is so important?
Well, there are several reasons.

1. One of them is due to population growth, which usually provokes city sprawling, and in so doing, cities are running out of space to build a landfill, and even when the landfill is full, it is difficult to develop constructions on it because dangers derived from cave-ins and gas escape. The problem is more complicated because usually landfills were built some time ago in the outskirts of the city, but these outskirts are no longer that. Residential areas are all around and even if the landfill was built decades ago over an interurban road, it is very possible that in the near future these urban places will be very close to each other, or even forming an urban agglomerate. So the landfill will be located in the center of an urban environment.
2. We mention gas escape?
   Yes, domestic waste in all countries is composed in a large percentage by organic matter, such as paper (which of course is cellulose), hardboard, food residues such as meat, vegetables, as well as yard grass, clothing, etc. When this organic matter is buried under tons of garbage and covered by a layer of dirt, there is very little air present. For this circumstance organic matter is attacked by anaerobic (living without oxygen) bacteria that slowly degrades this matter. This degradation is usually slow because the lack of oxygen.
   Excavations in landfills have found that in occasions it is still possible to read newspapers written 40 years ago
   
3. One of the products of the decomposition is methane (CH 4 ), an odorless, colorless, and a fuel gas. This is the reason for some fires in landfills. Once formed, this gas escapes to the atmosphere through the interstices of layers of garbage and dirt, and enters the atmosphere. Everything appears to be innocent; however, this gas is one of the main components that provoke the greenhouse effect and global warming, that are melting the ice in the poles. Its capacity to trap heat in the atmosphere is 20 times more effective than CO 2 , the other main culprit, together with water vapor.
   
   Many people will wonder why this methane is allowed to escape and it is not used as a fuel. As a matter of fact, it is; for is collected through pipes, purified and used as a fuel for engines that can move an electric generator and produce electricity.
   
   Figure 1 shows in percentage the average composition of waste in a landfill.
   
   
   

   Figure 1 Composition of garbage in a landfill
   Reprinted from Munier, N. “Handbook on Urban Sustainability” – Springer – Dordrecht , 2006

4. The other problem linked with landfills is contamination of underground sources of water. Normally a well built landfill is constructed on a depression in the ground. Usually the bottom of the landfill is covered with a layer of clay (bentonite), and this clay covered with several layers of a synthetic membrane, which is a tough plastic film of polyethylene (HDPE), called the bottom liner, and tightly welded one sheet with another in order to form a water tight barrier for leachate to reach the clay. Also, at the bottom of the landfill there is a network of perforate pipes in order to collect this leachate.

What is leachate?

See Figure 2 that shows a scheme of a landfill.

When it rains, water penetrates the dirt and garbage layers and reacts with the organic and inorganic substances dissolving them. Of course there are also many other fluids that come with the garbage as household products such as paints, beer, vinegar, oils, detergents, many different chemical from medicines, etc. This highly contaminate mix or leachate, reaches the bottom, and is then collected by the perforated pipes, conducted to a water treatment plant and decontaminated before discharging the liquid into a river. The remaining solid matter is then placed again in the landfill.

This is an effective way, however, the HDPE liner is not hundred per cent impervious because with time it degrades losing its characteristics, developing cracks, and allowing leachate to permeate to the clay layer, and, if there are cracks in it, to permeate downwards with the danger of reaching an aquifer.

Why the HDPE degrades? Because it is attacked by chemicals or a combination of them contained in the leachate, for instance alcohol, vinegar, and many others. On the other hand there are also mechanical forces at play because the weight of the garbage and its movements.

Figure 2 Sketch of a landfill
Reprinted from Handbook on Urban Sustainability – Springer – Dordrecht , 2006

In this brief analysis, it can be seen that landfills are not a convenient way to storage garbage, since it not only occupies valuable land but also contaminates upwards and downwards.

Which is then the alternative?

Many think that the best solution is to incinerate waste, and some countries such as Switzerland have prohibited the construction of landfills favoring the use of garbage incinerators. So, is this the solution?

Not really. Incineration plants are not only very costly but also have some inconveniences, such as:

•  As in the case of landfills nobody wants an incinerator nearby, so a more or less remote location has to be found. However, this is not an easy task. The incineration plant has to be strategically located in order not to incur in too high transportation costs for garbage. More important, it is necessary to choose the location considering the prevailing winds because, of course, nobody wants to receive the fumes and odors. This is a serious problem, considering that which could be an advantageous location for a city from the point of view of winds, could be very disadvantageous for another.

•  The main problem with garbage incinerators is that under certain circumstances their fumes can contains carcinogenic substances such as dioxins and furans.

•  It is also necessary to find a place to deposit the large amount of ashes generated.

Is there any other solutions?

Of course we are not considering abhorrent practices, as for instance the one used by the city of New York , that in the past threw everyday thousand of tons of garbage into the ocean.

Since that practice was abandoned, this city has to send daily large trains loaded with its garbage to another state where this waste is stored, at a hefty price of course, but there is no other alternative for this city, since it run out of space for landfills.

So, what is then the solution, if there is one?

Yes, there is a very efficient and simple solution and it consists in consuming less and producing less garbage. In reality there is a hierarchy of measures than can be used to decrease the amount of garbage to almost nothing, at least theoretically.

This hierarchy is, and in this order of importance:

• Reduce
• Reuse
• Recover
• Recycle

Reduce

the most important measure , involves consuming less of everything. For instance:

•  People should purchase in bulk many items such as flour, dried fruits, cereals, noodles, sugar, and thousands of more items, instead of paying for costly and useless packing. This is not utopian; there are hundreds of places that sell food products in bulk. With this, the consumption of paper, cardboard and plastics can be considerably reduced.

•  The use of plastic bags in supermarkets should be banned as is in Ireland , where shoppers use their own baskets, paper or fabric bags. Only this simple procedure impedes that millions of non-degradable plastic bags fill the landfills, and consuming thousands of cubic meters of space. There are several procedures than can be followed, which are based in charging a fee in accordance with weight.

•  Reduce the amount of garbage put up on the curb for collection, by classifying the different garbage items in paper, glass, metals, etc. There are procedures than can be used to make mandatory for the population to sort its garbage, as for instance exacting a unit collection fee based on weight. Obviously, a household will try to reduce its collection fees, and at the same time will take pains in separating all that is reusable and recyclable, because it is not necessary to pay by weight for these items

Reuse

Another very important procedure. Examples are:

•  Extending the life of discarded items such as clothing, toys, electrical equipment, kitchen and garden appliances, etc, by donating then to charitable organizations. Remember that what is garbage for a person could be a treasure for another.

•  There are lots of things that can be reused. For instance, a large coffee shop chain donates everyday thousands of kilograms of wad of coffee to be used as a very effective fertilizer.

•  Waste treatment plants can treat and reuse solid matter for fertilizer, while many factories and hotels use and reuse hundreds of times the same amount of water after properly treated.

•  There are household systems that can be used to recycle waste water, treat it and reuse it in toilets indefinitely. The city of Windhoek in Namibia reuses hundred per cent of its waste water as potable water.

Recover

Can be accomplished as in these examples:

•  By recovering parts of waste products, for instance recovering plastic and steel from worn out tires, wire from mattresses, plastics and metals from cars, copper wire from kitchen and workshop appliances, etc.
As an example, large carpet manufacturers such as Dupont, recovers the constituent material of worn out carpets to be used again

Recycling

Which involves collecting many items that properly treated and transformed can be used again in the same original product such as aluminum cans, bottles and paper.

Many plastics cannot be recycled to recover their original components (hydrocarbons) because they are the product of irreversible operations, however, they can be processed to get useful things. One of them are the plastic bags used in supermarkets, that can be reprocessed for instance into garden furniture. But as important as it is, a significant part of recycling feeds with excess consumption such as thousands of tons of paper used in newspapers, glossy magazines and advertisements, as the leaflets distributed by the post and that nobody reads.

The advantage of recycling is that usually, producing a new product out of an old one, is much less energy consuming that producing a new one with virgin material, and this is essentially true in aluminum cans, glass bottles, and certain kind of plastic such as de PET ( polyethylene terephthalate), bottles used for different drinks.

When all of these procedures are effectively applied there is very little that goes to the landfill, because even uncooked and cooked meat, fat, death animals, etc., are converted in useful products by the rendering industry.

The ecological footprint

Is there a way that we can measure the progress that has been made by a city using these procedures?

Certainly, there is one.

For measuring reduction we can take several ways:

• By accounting the amount of waste that goes to the landfill, usually measured in kilograms per person and per year. A yearly counting can indicate the trend.

• If the commented policy banning plastic bags in the supermarkets is enforced, the same commercial entities can give an accurate figure of the millions of bags no longer purchased and from there the amount of hydrocarbons saved. From here it is possible to compute the amount of land saved.

• Same happens with the use of bulk shopping. Prices of products will go down because there is no need of costly packaging, and at the same time the chemical industry can inform about the reduction, expressed in the thousands or tons of ink that are not longer used.

• The results of campaigns to reduce the domestic use water can be easily computed and measured by different ways, for instance considering the variation of the levels of water in the different water reservoirs that feed a city, and also through the metering devices installed in households by the entity in charge of providing water to the city.
  In general all cities have a serious problem because water lost due to cracks in the main trunks, and this loss is generally very important. If the city knows the quantity of water delivered out of the water treatment plant, and the total volume of water consumed by households and industries, it is possible to determine the order of magnitude of this loss and to take appropriate measures.

Reusing is measured by different ways also, for instance

• By computing the amount of water a city is consuming, and its trend.

• Visiting the outlets where used articles not necessarily old, are sold

• By the amount of garage and yard sales advertised.

Recovering can be measured by:

• Getting information from car manufacturers for instance, who in some countries are obliged by law to recover a certain amount of components, from his own old models.

• By visiting car junkyards and getting a statistics of how many parts from old vehicles are purchased before they are sent to the steel mills.

• By getting information from scrap steel dealers about how many tons of steel, aluminum, bronze, etc. they purchase.

Recycling, is most probably the easiest indicator to obtain since statistics have been kept since many years back about the amount of aluminum, paper, plastic, tires, etc, a city is recycling.

However, it is very difficult to get a composite index about how much a city is consuming of everything, especially considering that no city can survive with what is produced within its own limits or from the surrounding region or metropolitan area.

A city needs to import many different things for food, construction, clothing, industry, housing, etc.

There is however, a measure about how much a city needs to survive considering any kind of inputs and imports.

How can it be done considering the many different units of measure?

By using the concept of ‘City Footprint', developed by Mathis Wackernagel and William Rees. (Wackernagel, 1996)

This approach uses a very simple but powerful concept: It is expressed at determining how many hectares need a person to live . We are no talking here about the physical space that he or she occupies in his/her dwelling, for this is only a component of the whole issue; we need to compute everything.

Just to clarify this concept we propose this example: Consider the purchase of bread, and the following sequence:

1. A person buys the bread in the bakery, and in so doing occupies a certain space either in the sidewalk if walking, or on the road if driving from his/her home to the store.
2. The bakery itself needs a physical space measured en m 2 to prepare the ingredients and to bake the bread, and an area to sell it.
3. When the baker buys the necessary floor he/she also uses a physical space to go with his/her truck to the floor mill.
4. The floor mill in turn needs a physical space for processing the wheat, grinding, storing the flour and packing it.
5. The plant in turn, buys the wheat from the farmer using physical space in the roads and highways for its trucks.
6. The farmer of course uses hundreds of hectares to grow the grain.
7. In turn also uses space to buy the seed, the fertilizer, and the machinery that in turn need physical space to be manufactured………., and so on..

When all of these physical spaces are added up and after some complex calculations one can obtain a figure of how much space measured in hectares are needed for a certain population, and from here the per capita value.

Of course, this reasoning also applies to many other main activities such as going to work (necessity of streets and highways, parking space, office space), restaurant space, shopping space, and so on).

The final figure is staggering. The average area needed by a person computed by Wackernagel and Rees in 1996, is 1,8 hectares.

Naturally, the following thought is, “knowing the amount of people that inhabit the Earth today, how many hectares do we need, and more important, do we have them?”

This concept of quantity of hectares needed is called ‘ecological footprint', and the value of 1,8 hectares is called a ‘threshold' which, when breached will bring unequal benefits to rich and poor countries.

As it is now, and because many countries have for their people a footprint many times over this threshold value, the planet would be unsustainable if all people had access to the higher values existent in developed countries. In other words, the carrying capacity of the planet in that circumstance will be surpassed.

Look at the following Table

Comparison of footprints between selected countries

Source: Adapted with kind permission of Mathis Wackernagel

As can be seen industrialized countries use many times over this threshold limit. The logical consequence is that rich countries use more that their share of the available land at the expense of other countries. Compare for instance the United States with a footprint of 9,7 hectares per capita with even rich countries such as Sweden, with 5,5, or France with 5,6 or Germany with 4,4. Needless to say, if the comparison is made with developing countries the difference is enormous. Look for instance at Philippines with a footprint of 1, that is 9,7 less that the USA !!!

If you look at Pakistan with a footprint of 0,6, it means that a Pakistani person uses 16 times less land to live when compared with the USA .

Now the other question: What would happen if everybody could use the same amount as the American inhabitants do?

Simple. According to Wackernagel and Rees, we would need FOUR additional planets…..In other words; the planet will not BE SUSTAINABLE.

Applying this concept to cities, in 1995, urban sustainability specialist Herbert Girardet ( London , 2004), estimated that the UK capital's footprint was 125 times the size of the city itself. In other words, in order to function, London required an area the size of the entire productive land surface in the UK to provide the resources the city uses and to dispose of its pollutants and waste.

We can appreciate with these staggering figures that it is possible to measure how many resources a city consumes computing its footprint; naturally the smaller the better. When a city cuts its dependency, albeit not totally of course, in importing goods which volume can be reduced, in consuming less power that is produced far away, in sending less waste to landfills that are out of its limits, it is evident that the city is making progress towards sustainability.

References:

London – Greater London Authority (2004)
Title: Sustainable development - London 's ecological footprint

Munier, N. (2006) “Handbook on Urban Sustainability” – Springer,
Dordrecht , The Netherlands

Wackernagel, M., et al (1996). “An ecological footprint : Reducing human impact on Earth”. New Society Publishers, Gabriola Island , B.C., Canada .