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?

Landfilling

Hi everyone!

I hope that this idea to split the discussion in several and focused posts is useful. Therefore, avoiding long introductions, today it is time to talk about landfilling consequences.

Landfilling waste produces a considerable amount of gases, of which Methane and Carbon Dioxide are the most common. The thing is that CH4 and CO2 belong to the GHGs group (Greenhouse Gases) so, their production is strictly connected to the global warming issue (2014 IPCC's "Synthesis Report", page 4, 43 and 116 and 2014 DEFRA report "Energy from Waste", paragraph 37).

A work conducted by Daskalopoulos et al. (1997) shows concrete data about the amount of Methane and Carbon Dioxide in UK due to waste landfilling: the former is the 63.8% of the total volume while the latter is the 33.6%. Thereafter, besides global warming, the most relevant problems linked to landfilling are intuitively detailed by the authors as water pollution, risk of explosion (due to gas accumulation) and health problems (Daskalopoulos et al. 1997: 214 and 215). The same bad consequences can be found in other papers: El-Fadel et al. (1997) actually include also air pollution and vegetation damage.

In addition to the gases, both these papers talk about the leachate, which is the liquid result of the waste degradation. Leachate does not have a big influence in terms of global warming as much as gas does, but it is widely taken into account when it is related to water and soil pollution.
Again, the same list is highlighted in a really interesting report edited by DEFRA in 2011: "Applying the Waste Hierarchy: evidence summary" describes, for each different kind of waste (paper, aluminium, plastic and so on), what the favourite disposal methods are: landfilling is again the last favoured option and the reason is because of the high health, environment and climate change impacts that it brings.
Finally, there is one more aspect to account for: land availability. We have to consider that also the waste production is consequently growing together with the population. Therefore the landfill sites are getting full and there is an actual need to find new places to install new sites and new rubbish. A study conducted by King et al. (2006) tackles this issues and shows how the available land space is predicted to finish. Moreover, the three researchers lead their work explaining how, also in the land availability context, the general concept of recycling is the key tool to treat waste in the next future.

After this brief summary about landfill implications, I have to keep following up the “Waste Hierarchy”: as explained in the previous post, I want to reach to top of the triangle starting from its base. The next step is thus related to incineration, which will be the topic of the next post.

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!