"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!

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!