Circular flow mathematics

If 1 kg polyethylene plastic is recycled and reused the carbon dioxide emissions will be reduced by about 2 kg compared to use of virgin material. The crude oil consumption will also be reduced by 1 liter.

The Waste & Resources Action Programme (WRAP), which was created as part of the British Government’s waste strategy, presented in autumn 2006 a report said to be the most comprehensive international review of life cycle analysis carried out in the recycling area. Technical University of Denmark conducted the study commissioned by WRAP. The report studied 55 life-cycle analysis, with a total of 200 different scenarios, carried out in a dozen European countries, including Sweden, USA and Australia. A comparison between recycling and incineration reported the average climate benefits of plastic to 2 tons of carbon dioxide per ton of recycled plastic [see page 21,”Återvunnen råvara – en god affär för klimatet”, www.co2minus.info].

Environmental Strategies Studies (FMS) at KTH, presented the 2005 report, “Robust and flexible strategies for exploitation of energy from waste”. The report’s overall conclusion is that increased recycling of plastic, leads to significant reductions in greenhouse gas emissions [see page 17 , “Återvunnen råvara – en god affär för klimatet”, www.co2minus.info].

CIT Ekologik (Chalmers Industrial Technology), Gothenburg, Sweden, conducted in 2004 an analysis of environmental data on the recycling of plastic (HDPE) “Recycling of plastics – an analytical overview”. The study compares energy use and greenhouse gas emissions in direct incineration of plastic packaging with a scenario where the packaging is recycled only once and then goes to incineration. The results show that greenhouse gases will be about 1.5 to 1.8 tons per ton lower in the case where plastic is recycled once before it is incinerated. The lower figure corresponds to an efficiency in the recycling of 53 percent and higher efficiency to be 75 percent. [See page 17 “Återvunnen råvara – en god affär för klimatet”, www.co2minus.info].

CIT Ekologik (Chalmers Industrial Technology) conducted in 2002 an analysis of environmental data for six different materials, “Environmental Benefits of recycled raw materials”. The study compares energy use and greenhouse gas emissions in the manufacture of recycled raw materials to manufacture from virgin materials. The results are reported both as emissions from the electricity used in manufacturing are not taken into account and also when these emissions are covered. If electricity consumption is included in the calculations, carbon dioxide saving 1.66 tons of carbon dioxide per ton of recycled plastic. If electricity is not included in the calculations, carbon dioxide gain 1, 9 tons per ton of recycled plastic. [See page 16 “Återvunnen råvara – en god affär för klimatet”, www.co2minus.info].

Based on the above reports Miljösäck is using the ratio: 1 kg of recycled plastic results in 2 kg carbon dioxide reduction. This is an approximation that makes it easier for our customers to quickly calculate the carbon gain from the use of products made from recycled plastic.

Recycled polyethylene – a step in the right direction

Polyethylene is the most common plastic and fully dominating in packaging plastic industry. It is very useful – flexible, strong, takes very little space and is price worthy. Polyethylene is besides a harmless plastic.

The disadvantage of polyethylene is that it is manufactured from crude oil which is a finite resource and it results in carbon dioxide emissions at incineration.

Miljösäck recycles polyethene that has been collected in Sweden after use (post consumer material). From this we manufacture sacks and bags. In this way a recycling loop is completed one turn.

Manufacturing new products from recycled polyethylene results in two important effects on the environment. First – the carbon dioxide emissions are reduced during the life cycle of the plastic and second – the consumption of crude oil is reduced.