"Recycling: yes or not?"

Hi bloggers!

After a while, it is now time to complete the “Recycling: yes or not?” discussion. That will roughly take two more posts, I promise.

The conclusion of the last post introduces what I am going to talk about today: in the next paragraphs, I will analyze the remaining disposal methods. In order to do that, these posts will be mainly based on the “Environmental benefits of recycling – update 2010“ report, edited by the Waste & Resource Action Program (WRAP – www.wrap.org.uk). This document runs a clear excursus across all the waste treatment methods, highlighting the best disposal solution for every different type of waste. Moreover, it is focused on the Municipal Solid Waste and, obviously, it analyzes also landfilling and incineration. Considering that these two disposal options have been already discussed, I will be mostly talking about Composting, Anaerobic Digestion and Pyrolysis in comparison to recycling.

Before analyzing in detail the contents of this report, I would like to get started with a significant sentences available in the summary (page 1):

“The conclusion was clear – most studies show that recycling offers more environmental benefits and lower environmental impacts than the other waste management options”.

Right, the scheme followed by the report is structured according to the different type of waste. For the first one, cardboard, it is shown that landfilling, incineration and recycling are the most common treatment. Same consideration can be found in other works like Arena et al. (2004). As well as WRAP report, the authors actually note that for paper, incineration could be sometimes better that recycling because it allows higher ratios in terms of energy recovery. Considering instead both the water usage (quite high for incineration) and energy request, recycling seems to be the best option. In 2014, Bajpai totally promoted paper recycling instead: indeed, his work points out how paper produced from recycled material requires less energy, prevent virgin material employment and reduce environmental pollution (Bajpai 2004). 

Same conclusions have been traced by a Swedish study. Herein, the authors show how "the potential saving that can be made when going from incineration to recycling is 1.2 million ton CO2 -equivalents" (Finnveden et al. 2005: 225).

Concerning plastics, recycling is overall ranked as the best option in terms of climate change (low impact), energy demand as well as water request (low as for paper). Pyrolysis is also considered as a preferred disposal methods because it is the treatment that shows the lowest toxics effects on human health.

Also Quian et al. (2014) promoted the pyrolysis process: considering before the advantages of recycling, as it helps to protect the environment and reduce the use of natural resources, they illustrated that, with its considerable heating value (Kiran et al. 2000), plastic represents the right ingredient to produce a more calorific fuel.

The problem of recycling plastic consists in its costs: how explained by Eriksson et al. (2005), recycling plastics presents the lowest consequences but, at the same time, the highest outlay. However, the same study explains how the general term “recycling” means reducing the environmental impact as well as softening the demand of energy resources and also limiting the economic expenses.

Anaerobic digestion (AD) and composting are taken into account especially when food and organic waste are involved but this, with few more important bits, will be the topic of the last "Recycling: yes or not" post.

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!