"Recycling: yes or not?"

Final post.

Hi everyone!

It is definitely time to give an end to the “Recycling: yes or not?” discussion. I closed the last post shortly introducing the food waste and its related disposal methods. Hence, today I get start from there and afterwards I will briefly write about glass and textile treatment. Also this post will be principally based on the WRAP report “Environmental benefits of recycling – 2010 update”.

So: food waste. Anaerobic digestion (AD) and composting are the two most common ways to treat organic food waste. Basically, there is no chance to literally recycle food waste. The most favored procedure is probably the AD: a study conducted by Finnveden et al. (2005) listed the advantages as the production of biogas, used for both electricity and heat, as well as fuel for vehicles. Moreover, the WRAP report explains that AD is a powerful option also in terms of global warming impact: the biogas produced is mainly composed by CO2 and CH4 and, rather than being released in the atmosphere, they are exactly collected and used for energy purposes. Precisely, the less global warming impact marks the difference between composting and AD: in fact, the former shows here more influence compared to AD. Moreover, AD allows also a higher energy recovery than composing (Mata-Alvarez et al. 2000). A confirm comes also from the WRAP report, which exactly list composting as second preferred option after AD. However, composting represents, for instance, one of the easiest and most immediate techniques to domestically well treat our food waste. Finally, WRAP shows also that incineration (with energy recovery) could give good results when organic waste is involved: this is the specific case of garden waste, which obviously guarantees a remarkable heating value.

Chynoweth et al. (2001) edited another significant AD-related work: here, the authors strongly emphasized the key role of the AD, explaining how the society would gain considerable advantages using natural-methane instead of the traditional fossil fuel and, at the same time, that would mean a further action against global warming and acid rains.

Glass. Finding scientific and complete information about glass treatment has not been that accessible. However, I managed to find few useful papers about recycling and landfilling glass waste. The main disposal methods about glass waste are exactly the two just listed (Sahyan and Xu 2004). Moreover, this paper explains also what the main “second-live” of the glass is. In fact, the authors give evidence that the glass is an important ingredient for the formation of concrete aggregate and, noticeably, they explain this reusing technique as a key tool to reduce landfilling. Shao et al. (2000) have been even more specific: indeed, they assert how glass is non-biodegradable and, therefore, totally non-adapts to landfilling. In addiction, this paper shows again the important role that glass covers concerning concrete production as well as mention recycling as other alternative destiny for glass waste.

Concluding as the WRAP report does, I wish to say something about textiles, a quite common component of MSW. The document displays the end-of-life of clothes as second-hand stuff, recycling (mainly referred to a reusing concept) and waste, which ends up in incineration or landfilling. Predictably, there are a lot of ways to prevent the incineration/landfilling of textile waste and this is exactly the main evidence of the report, which lists a quite long series of second-life possibility for this kind of rubbish. More specifically, Woolridge et al. gave, in terms of energy saved, some precise number when analysing donated clothes: “for every kilogram of virgin cotton displaced by second hand clothing approximately 65 kWh is saved, and for every kilogram of polyester around 90 kWh is saved. Therefore, the reuse and recycling of the donated clothing results in a reduction in the environmental burden compared to purchasing new clothing made from virgin materials” (Woolridge et al. 2006: 94).

Obviously our homes and flats are not well equipped for collecting textile but, in London as anywhere else, there is a bunch of Oxfam and similar charity shops.

Briefly concluding with gasification, not mentioned so far. As explained in this post, we can consider gasification as a well-improved incineration. Malkow (2004) developed a very articulated work about the different kinds of gasification (and pyrolysis), explaining how it leads the way to a high energy saving and less environmental impact compared to incineration. Moreover he pointed out the benefits considering the less amount of emissions released in the atmosphere. Its position in the Waste Hierarchy is thus quite well positioned.

Well, it ended up a massive post. I tried to summarize the big amount of information of the remaining issues and I am aware that there would be a lot more bits to talk about. Anyway, I hope that I gave a quite fair and scientific idea about why recycling is up there in the Waste Hierarchy: it generally represents the best compromise between energy demand, environmental and healthy impacts. Moreover, leaving the science for a moment, I personally find so ridiculous just bin our waste when it could have such a considerable number of second uses and second life.

Importantly, recycling is not the highest position in the Waste Hierarchy. The following posts will be thus dealing with the remaining two RE: reusing and reducing. Finally there will be space for some more posts regarding recycling@UCL, few initiatives and a future work discussion.

See you soon on RE-cycling!

Recycling: yes or not?

Incineration

Back again on RE-cycling!
Let's restart the debate that I started few posts ago. Today it is time to talk about the incinerations’ impact.

Incineration consequences are involved in two main fields: global warming and human health. In both cases, the original factor that needs an accurate analysis is the gas emissions. Despite the combustion of waste does not release methane, in terms of global warming incineration is problematic because of the amount of CO2, N2O and NH3 emitted ("Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories" IPCC 2000, page 455). Instead, considering humankind health, Daskalopoulos et al. (1997) explain how municipal waste combustion released "polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF)" (Daskalopoulos et al. 1997: 226). These are generally known as toxins and they are considered causes of skin and liver diseases as well as cancer. Moreover, the same authors say that also metal compounds, heavy metals and acids gases are a result of waste incineration and also involved in the human health concerns.

However, comparing incineration to landfilling, it is easily noticeable that:
1. gaining and using energy from incineration is easier rather that from landfilling. Indeed, as highlighted in “Incineration of Municipal Solid Waste” report (DEFRA 2013), from incineration there is a substantial gain of usable energy in terms of heat and electricity.
Even though successful attempts have been done, energy recovery from landfilling is in fact a quite expensive procedure and it is mainly discussed as a possibility rather than a convenient and actual opportunity (Lombardi et al. 2006).
2. intuitively, incineration reduces the volume of waste. This means that less rubbish is thus dispatched to the land. Moreover, the residual bottom ash can also be reused in other engineering fields like road building (Incineration of Municipal Solid Waste, DEFRA 2013).
3. as explained in the UK Government report “Waste GHG Inventory Summary Factsheet”, the emissions from landfill represent the biggest amount of Green House Gases concerning the waste management (incineration does not produce CH4). In 2010, 89% of UK waste disposal gases came from land and just a minor part from incineration.
4. finally, another evidence is that water and soil pollution are mainly related to the leachate derived from the landfilled waste. Water contamination coming from incineration is minimal (Daskalopoulos et al. 1997).

Keeping in mind the energy recovery concept, I would say that with this post we have learnt why landfilling is at the bottom of the “Waste Hierarchy” and why the incineration is located in a slightly better position.
At this stage, we have to keep climbing the hierarchy as well as keep comparing the different disposal method each other. In the next few posts I should be able to conclude the current discussion and hopefully I will have fully explained the RE-RE-RE importance.

So...see you soon on RE-cycling!

Recycling: yes or not?

An introductive chat

It has been a while since I’ve post a new piece of writing so today I want to keep talking about the issues I left in ice at the end of “Digging the Topic – part 3”. Basically, I want to understand whether or not the recycling process is important and, if yes, why. I am aware that the answers can be easily taken for granted, but the aim is to tackle this topic with a scientific approach. Then, considering that it will be probably a long discussion, I am going to split it in different posts. "Recycling: yes or not?" will be the title of every post while the subheading will address every single post.

I believe that the right starting point consists in talking about the disposal method that do not include energy recovery. Why? Because landfilling and incineration are widely evaluated as the worst existing waste disposal options and, at the same time, they represent the most widespread waste treatment. Figure 1, taken from the 2011 EU’s publication "Generation and treatment of municipal solid waste", refers to the European situation and it schematically shows how much common landfilling and incineration are when compared to all the other main waste disposal. Indeed, in 2009, these two treatments were used to treat more than half of the total amount of European waste (278 on a total of 492 kg for each inhabitant).

 Figure 1: schematic waste treatments usage according to the EU's website

(y=kg procapita; x=years). Click to enlarge.

Surely, the image shows also how that landfilling operations decreased between 1995 and 2012 as well as recycling increased but, according the Directive 2008/98/EC of the European Parliament and of the Council, this positive trend must be only a starting point. As I mentioned in the previous post called “2020 is getting closer and closer” the European Community advised both that landfilling must be further reduced and that, by 2020, the recycling ratio needs to reach the 50% in weight (nowadays England is at 43%).

Giving this discussion a worldwide perspective, a huge challenge is for the developing countries. An example comes from an interesting work about the waste typology and disposal methods in 6 Asian country. Indris et al. (2004) explain how important is the waste debate in those countries where the amount of rubbish is prominently growing together with the population. Ignoring the discussion about the different kind of waste, the authors show striking data like China’s landfilling percentage, which reached 96% in 2011. In other countries, like Taiwan and Malaysia, is also highlighted how landfilling and incineration are the most common used methods for getting rid of most of the rubbish. Summarizing, this paper is highly useful because it tells us the importance of gaining a wider knowledge about waste disposal in those countries where the amount of waste is getting higher and higher. The concern is aimed to prevent environmental and health issue that frequently arise from a bad waste management know-how.

I think that this sounds as a good introduction post to the following discussion. My aim consists in exploring the advantages of the recycling by understanding first all the concerns and limitations related to the other disposal methods. I will start thus from the bottom of the “Waste Hierarchy” (click here to refresh your mind about it) and, through the less favourite disposal methods, I will hopefully show why the “RE-RE-RE” are located at the top of the triangle. Hence, the next posts will be dealing with few considerations about landfilling and incineration.

See you soon on RE-cycling!

Digging the topic - part 3

From here to there

Hi everyone!

The last post I wrote on RE-cycling had interrupted, in a way, the "Digging the Topic" series that I was writing up. Hence, I think it's time to end the trilogy with the last piece of writing. With "Digging the topic - part 3" I will briefly give an overview on all the destinations of waste once collected from our houses, offices and premises. Therefore, following the guideline purpose of my blog, I will be focusing mainly on the MSW (Municipal Solid Waste).

Once collected, the waste starts a journey that ends up somewhere: the waste disposal methods explain in detail this somewhere taking into account all the possible options for the community to get rid of its scraps. Having a look at Figure 1, the Waste Hierarchy described in the newest Defra report “Waste Management in England” helps us to have a better idea of the term "disposal": the bottom of the arrow defines the disposal as an option with no energy recovery while, other disposal methods such as anaerobic digestion, gasification or pyrolysis, are ranked as other recovery because there is a production of reusable energy from their application.

Figure 1: waste hierarchy according to the "Waste Management in England" report (Defra) 

Recycling could be also considered as a disposal method because it is a (great) method to treat the waste. Anyway, we could generically list the disposal methods as follow:

1. Recycling (…and I don’t need to say what recycling is about)

2. Composting. The most complete definition I found out there was provided by Lau et al. in 1991: “controlled biological process which converts biodegradable solid organic matter into a stable humus-like substance” (Lau et al. 1991: 145). Another interesting paper written by Slater and Frederickson (2001), explains what composting means and involves. At this stage of the discussion, what is relevant among the huge amount of information provided is that composting refers mainly to kitchen and garden waste (more widely, it is a biodegradable-waste related method), it is a biological treatment, its output is used as fertilizers in agriculture or in reclamation projects.

3. Anaerobic digestion (AD). I am talking again about organic waste, yet treated in an oxygen-free environment (Alvarez et al. 2000). The outcomes of this technique are very interesting. In 1995, Braber presented a wide overview of the AD advantages, such as the considerable production of energy, reduction of CO₂ emission and, as well as for the composting, less land requirement.

4. Gasification and Pyrolysis. Here, taking a break in citing papers, I found an extremely useful webpage (www.gasification.org) which deals with this disposal methods. Basically, they both consist in burning waste but the former involves high temperature and an aerobic environment while the latter occurs at lower temperatures, it is anaerobic and it uses an indirect source of heat. The most important thing to say is that these methods allow high energy recovery ratios while the simple…

5. …incineration, an aerobic high-temperature waste combustion, often doesn’t. For fully understand the incineration process and its differences with gasification, I think it is time to link the first video.

6. Landfilling, which is the act of placing waste into specific portion of land. All official reports, environmental organization and, above all, the EU, describe landfilling as the last favourite way to treat waste. The reasons are quite straightforward if we consider all the disadvantages that it brings. In 1995, a number of these consequences have been listed by El-Fadel et al. as "gas and leachate generation, […] the migration of gas and leachate away from the landfill and their release into the environment, […] potential health hazards, vegetation damage, […], ground water pollution, air pollution, global warming" (El-Fadel et al. 1995: 1).

Well, the list above wanted to be an overview of the disposal methods together with a brief description of the relative main features. Therefore, concluding “Digging the topic – part 3”, I would say that this post has the double function to explain what the destiny of the rubbish is and, at the same time, to introduce automatically the following discussion: what are pro and cons for each method? In more generic terms, why is this specific sector of waste management so important? Hence, do we have to care about recycling? If yes, why? Looking back at Figure 1, it is clear how Defra wants to make clear that incineration and landfilling are the last favoured option to treat waste. At the same time, RE-RE-RE are at the top of the arrow so it looks like that a clear trail has been blazed. The following posts will be debating the questions above and I will try to understand what responsibility of the masses is within the waste process.

See you soon on RE-cycling!

Digging the topic - part 2

How much waste do we produce?

Once described the typology of waste that we produce (have a look at previous post if you have not done yet), I would like to take into account some data about the waste production to better frame the topic.

If we consider the waste production on a European scale first, the European Commission website shows that, in 2010, 2.5 billion tons of rubbish have been produced in the EU-27 area. Figure 1 shows all kind of waste generated but, for the aim of this blog, I will focus mainly on the light green sector of the pie chart: this is the 37% of the total, that is 927 million tons, something like 1847 kg for each inhabitant. Why is this the main data of the pie chart? Because the MSW is included within this sector. As we can see, the recyclable waste covers the 10% of the total amount, which corresponds to 255 million tons of materials.

Figure 1: European waste production in 2010 according to the European Commission web site.
Within the 37%, the recyclable percentage is pointed out: 10% of the total, 255 million tons of the total. (click to enlarge).

If you want to go more into detail about the quantitative aspect of the waste production, the Main Table links of the European Commission website show several interactive tables, graphs and maps that can give a wider understanding about all the types of waste generation, treatment and classification. Here I show the map of the European recyclable waste production: in 2012 the countries that produced the biggest amount of recyclable products have been United Kingdom, France and Germany while the eastern part of Europe shows the lowest ratios (note that this is not the quantity of waste that has been recycled, but it is just the production of potentially recyclable material).

Focusing on the UK situation, the Defra report mentioned in "Digging the topic - part 1" says that an average of 430 million tons of waste is produced every year in Great Britain. MSW is 7% of this total, corresponding to 29 million tons. Comparing the UK value with the European data, we can assess that Great Britain produces around 1/9 of the European recyclable waste.
Similar quantity can be found in the recent Defra report "UK statistic of Waste 2010 - 2012". In 2012, UK produced 26.4 million tons of recyclable waste. Going on an even smaller-scale, I only consider England now: the UK Government web site and the report included on it "The role of waste prevention in moving to a more resources efficient economy" assess that 177 million tons of waste have been produced in 2010. Contrasting this data with the values explained in the "UK statistic of Waste 2010 - 2012" report mentioned before, we can notice that, of a total of 177 million tons of waste production, 22.15 million tons are MSW produced by England alone. More clearly, MSW of England is about 1/8 of the total amount of waste produced.

In sum: I showed here some data regarding the amount of waste production. I started with a European overview, then zooming on UK and finally on England only: in 2010, Europe produced 2.5 billion tons of waste of which 255 are recyclable. In the same year, UK produced 29 million tons of recyclable materials. Of this, nearly all the amount was produced in England (22.15 million tons).

The question now is: how should we behave with all this quantity of rubbish? Where do we place it? "Digging the topic - part 3" will be dealing with these questions.

See you soon on RE-cycling!

Digging the topic - part 1

MSW: metal silicon and water or Municipal Solid Waste?

In the welcoming post, I tried to explain a few general concepts about what "recycling process" means, defining also "reuse" and "reduce" as two highly related and essential actions. Focusing on the waste, I basically pointed out that most of the rubbish that we produce has a second life.

At this stage of my blog, I would like to go more in depth about few more waste topics in order to have a more precise idea of the issue in terms of typology, quantity and treatment. Therefore, I divided the discussion in three parts. In "Digging the topic - part 1" I will address the waste classification, in "Digging the topic - part 2" I will briefly deal with the waste production while in "Digging the topic - part 3" I will analyse how the waste is treated once collected.

Listing the categories of waste is an essential starting point because it helps to create an overview of all the items that we constantly throw away. According to the UK Government website, the waste classification includes:
1. Construction and demolition waste (tiles, ceramics, bituminous mixtures, etc.);
2. Packaging waste and recycling;
3. Electronic and electrical equipment (batteries, televisions, laptops, tablets, furniture, WEEE, etc.);
4. Vehicle and oily wastes (consists of all the items related to ELV, “End of Live Vehicles”);
5. Healthcare waste (pharmacies, hospitals and clinic related waste);
A similar classification of waste is presented in the "Review of Environmental and Health: Effects of Waste Management" report (released by the Department of Environment, Food and Rural Affair - Defra) and it includes also agricultural waste as well as mine and quarry waste. Instead, the European Commission, suggests more distinct waste categories, including specific items such as POPs (Persistent Organic Pollutant), PVC or Sewage Sludge. Moreover, it splits the electronic devices in several different subcategories: batteries, WEEE (waste electrical electronic equipment), television, furniture and so on.
Nonetheless, the most evident and common element of all these classifications is represented by the Municipal Solide Waste (MSW), a term that includes sub-groups of waste like packaging or recyclables. It basically refers to all the waste coming from our houses, offices, schools and commercial activities (figure 1): plastic, paper, glass, textiles, shoes, food waste, cans etcetera. I will be using the acronym MSW quite often because most of the topics, processes and implication that I wish to talk about fall within this group. Moreover, the MSW is by far the type of waste that most commonly involves the humankind.

Figure 1: waste classification according to the "Review of Environmental and Health: Effects of Waste Management" report (Defra - 2004), modified. Main attention for the MSW, no quantity information are mentioned. (click to enlarge).

 

Last but not least, there is a different approach of waste classification which divides waste in two big categories: hazardous and non hazardous, depending if contains materials defined as "harmful to humans or the environment" (e.g. asbestos, solvents, chemicals, pesticides, etc.) or not. If we have, for instance, a plastic bottle contaminated with asbestos, it will be firstly considered as a hazardous waste rather then a simple MSW. However, this kind of waste classification needs a more careful consideration and I will discuss it properly in a future post.

Summarizing "Digging the topic - part 1", I described what kind of waste we produce by presenting the classification taken from the UK government (using both the website and Defra reports) and the typology offered by the European Commission. Among the main categories, I gave more attention to the Municipal Solid Waste (MSW) as it is a kind of waste that we most produce everyday: cardboard, paper, packaging, plastic, cans, etc.

I am going to post "Digging the topic - part 2" in the next days where I will give some data about how much waste we produce.

See you soon on RE-cycling!