"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!