Inoculació simultània amb els dos cultius d’ Agrobacterium

End of life scenarios are usually based on a 60 year lifecycle (NNFCC, 2008). Both natural and man-made fibre insulation may have accrued water sorption over this lifespan whilst petroleum based rigid board insulations may have degraded so as to not perform properly (Norton, 2008). It is upon reaching this stage that many insulations are rejected and replaced.

2.6.1 Fibreglass and Mineral Wool

The glass particles and particulates within fibreglass actually originate from recycled sources. The glass originates from recycled glass bottles. The wool used in the insulation is derived from molten raw materials centrifuged into the desired fibrous form (Letcher & Vallero, 2011). These insulations are difficult to recycle, or to salvage any usable components from them, and so they usually find their way to landfill sites (Raviv & Lieth, 2007). However a small percentage of wool waste is used as landfill cover and sometimes mixed with poor clay soils to improve the soil’s physical properties (Raviv & Lieth, 2007).

2.6.2 Multifoil Insulation

Although multifoil insulation has been used in France since the 1990’s, this is not long enough to generate enough waste from demolition or refurbishment projects to gather reliable data on the product’s end of life capabilities. In the future when it does get discarded and replaced, there could be a recycling market for both the metal foils and the felt inner. However, Briggs & Leyworth (2009) opine that the retrieval of foils would not be cost effective when comparing the weight ratios to the collection and sorting costs.

2.6.3 Petroleum Based Insulation

If and when crude oil extraction slows down from current levels, some may see this as a relief from the poisons created from oil based product manufacture to slow down also and as a catalyst for the environmental recovery to speed up (Haigh & West,

2009). However, regarding the end of life disposal of synthetic insulations, an important question would remain. Would the ecosystem suffer as a result of the product being buried in landfill or incinerated, giving off potentially toxic pollutants over time? Typically these pollutants could include petroleum hydrocarbons, heavy metals and solvents. Some of these pollutants have been linked to chronic health conditions (Wilhelm & Bloom, 2012). A summary of the various insulations and their end of life disposal is shown in Table 1 below.

Insulation Type Reused/Recycled or Landfill

Fibreglass Landfill

Mineral Wool Reused/Recycled

Multifoil Landfill

Polystyrene Landfill

Polyurethane Landfill

Soap Reused/Recycled

Table 1: End of Life Disposal for the Various Insulation Types

It would appear that the shorter the time required for composition, the shorter the time for pollutants to affect the ecosystem. As an example, a plastic bottle can take 100 – 1000 years to decompose in landfill (Jones & Jones, 2013). This figure can be brought down to three months if the bottle is heated to 60o_{C and introduced to air and} digestive microbes (West, 2010). Rae (2009) partially agrees, challenging the idea that plastics will degrade in a thousand years or less, and in fact opines it takes at least double this time frame for petroleum based plastics to biodegrade. According to Fornasieror & Graziani (2006) petroleum plastics have been designed to resist degradation. However, it could be argued that the limited research into plastic degradation means limited damage to the plastic manufacturing industry per se. As previously mentioned, plastic degradation at landfill should be taken into consideration. Also, degraded (waste) oil, the key ingredient of plastic, must also be disposed of when it comes to the end of its useful life. According to the Environment Agency (2012), there are approximately 3000 pollution incidents involving oil and fuels within the UK annually. Waste oils also have to be disposed of according to the controlled waste regulations. In the UK, 16% of all pollution incidents annually involve waste oil (Environment Agency, 2012).

Europe-wide, approximately 67 million tons of plastic waste is dumped in landfill sites annually (Palm et al, 2015). This includes waste plastic thermal insulation. To combat the longevity of landfill plastic waste, additives can be added to the plastic at the manufacturing stage which will degrade the plastic to nothing in a matter of months. (Gho, 2012). Also, according to “Earthtalk” (2012), oil and petroleum-based plastic will rapidly degrade with exposure to water, oxygen or sunlight. However, opinion is divided. According to Massey (2007), neoprene rubber or foam type plastics will resist all three. Because plastic waste is relatively lightweight and landfill reduction targets operate on a weight based tipping system, this can discourage some local authorities from recycling their plastic waste (Davies, 2006). The environmental impact of crude oil retrieval, plastic manufacture and disposal of waste petroleum based insulation could justify the need for environmentally friendly alternatives, using environmentally friendly plastic components as part of the insulation body.

2.6.4 Recycling the Plastic Insulation

Manufacturing from natural and recycled materials helps to preserve natural resources (Palm et al, 2015). After all, the energy needed to produce 1kg of plastic could illuminate a 100-watt lightbulb for 56 hours (Jones & Jones, 2013). In addition, the cost of manufacturing a plastic product from recycled plastic content is four to eight times cheaper than starting from fresh (Jones & Jones, 2013). Recycling also helps to keep the end of life products out of landfill sites, saving money on transportation, tipping and burying costs. It will also reduce the amount of methane given off by the landfill sites as the products rot down. If the product naturally biodegrades, it could also help with the aesthetic appearance of the environment. After all, “the middle of the Pacific Ocean is six times more abundant with plastic waste than zooplankton” (Coburn, 2013).

If the plastic products can be recycled at their end of life for use into an alternative product, a reduction in energy spent and materials sourced mean financial, labour and environmental savings. It could be debated that landfill sites can be used as methane traps to capture the gas to use for energy. Also at the site’s end of use the area can be capped and used as parkland, woodland, nature reserves or areas designated for non-food production (bio-oils). From a financial perspective, probably most important for the waste industry, it is ten times more expensive to recycle than

to tip at landfill (Coburn, 2013). Recycling waste is just one area of sustainability. There are other alternatives, such as the new build and refurbishment of properties using ecologically friendly methods of construction, adhering to sustainable guidance and legislation.