the day. Fortunately, some brave and far-sighted politicians have taken initial action. California has now legislated for all textiles containing polyester fibre to be clearly labelled with the percentage. This presumably reflects the finding, previously reported in LCN, that several hundred thousand of microscopic polyester fibre fragments are discarded from every wash process involving polyester and blends of this. This finding applies to both commercial and domestic washes. The obvious initial approach to reducing the effect on the environment of this enormous daily number of micro- particles from laundering is by filtration. Yet to date LCN has only discovered one country, France, which has taken the very reasonable initial step of reducing this massive source of particles. This year LCN understands that every washing machine sold in France for domestic or industrial washing will be required to be fitted with a drain filter capable of removing the bulk of these micro-particles. There are two very different groups of filters now on the market, one relying on a fine screen and the other on a hydro- cyclone. The screen, relies on simple physical catchment; the hydro-cyclone embodies induction of high-speed rotation of the discharge, flinging the particles to the edge of the device for collection and ultimate removal. Both envisage periodic cleaning at approximately weekly intervals to maintain
efficiency. This is deemed commercially viable and reflects the fact the total weekly volume of microplastic contamination is quite low – even several million micro- particles do not represent very much fibre loss. The contamination is currently deemed suitable for normal disposal as non- hazardous domestic or commercial waste. The Xeros organisation in the UK has spearheaded the hydro-cyclone and they have a successful unit on the market worldwide, which can be accommodated as original equipment into any standard washer design. There are several suppliers of simple filtration devices now on the market, most of which appear capable of installation as original equipment or of being retrofitted. It is interesting to note that when the French authorities commissioned testing of removal performance, prior to drafting their new law, the hydro-cyclone was reported to give the best removal, although most devices took out over 95% of the critical micro-particles (which is a promising start).
Recycling can also produce toxic chemicals
The appearance in recycled plastics of chemicals already known to be harmful was surprising, given the enormous reliance now placed on recycling to solve the build-up of plastic waste worldwide. More research is clearly needed to determine the full range of chemicals involved and the levels at which these
might pose future problems. This finding does not reduce the important role which maximum recycling will play, but it might flag up the need for purification of the recycled product. It could even reveal possibilities for the collection and sale of valuable by-products.
Degradation of plastic contamination Several research laboratories worldwide have started trials on potentially economic methods for breaking down plastic waste (including the tiniest microplastic particles), because work has already shown that relying on natural degradation is insufficient. For example, polyester takes around 500 years to degrade. The most encouraging results have involved specific bacterial micro-organisms and some of these have shown remarkable results, including splitting long chain polymers back into the original monomers (offering the potential to use the monomers to recreate virgin plastic). One important piece of research has found a method not only of breaking down polyester, but also of doing this for polyester-cotton without degrading the cotton component (reference 5). Early research on the use of bacteria found that heat energy was required to maintain the breakdown, which placed an unwelcome financial cost on the process. More recent work has discovered how to use bacteria from within the Arctic Circle to achieve degradation without the need for external heating (reference 6).
Development of novel plastics There has also been success with novel plastics, which can be designed to be recycled readily into their original constituents (reference 7). Recycling is essentially designed into the construction of the novel plastic molecule to give an economic low-energy process with high efficiencies on the amount of original constituent recovered. However, when one looks at the time it has taken mankind to develop useful products (such as polyester fibre and polycotton textiles), the prospect of repeating these successes around a novel plastic does look somewhat daunting. Perhaps this makes reliance on replacement of current plastics with novel recyclable ones a longer-term project.
The way forward
SEAWATER SAMPLES: Wide variety of microplastic particles now found consistently in seawater samples worldwide
Although achieving zero discharge of micro-plastic particles into our oceans
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