Plastic waste and oceans of opportunity (Day 151)

Plastic waste and oceans of opportunity (Day 151)

25th October 2014

I've been travelling extensively over recent weeks in Australia, Malaysia and Singapore.

Like many people, I use online news media to keep in touch with what is going on at home and around the world.

Scanning the UK news headlines earlier this week there was lots of stories of interest to chemical engineers; fires at power stations, new bills to allow the use of untested drugs, the introduction of charges for plastic carrier bags; and the growing Ebola problem.

The story about plastic bags may seem the least 'serious' of these stories, but it has been a problem for many decades and it may be the most difficult to solve in the long-term.

Many of us see, every day, rubbish in our environment. Of that, plastic is a huge offender and examples of the environmental impact are often reported. One of the main issues, which many of us do not see, is ocean pollution.

Over the last couple of days, I found out about an organisation called The Ocean Cleanup set up by a young engineer Boyan Slat. I accept he’s not a chemical engineer but reading about the work that his group are doing, I can see many opportunities for the application of chemical engineering principles.

Like many of the problems that chemical engineers address, prevention is better than cure, however, we need to address what has already happened.

Every year, millions of tonnes of plastic enter the world’s oceans. On a small scale some gets washed up on beaches and local communities work to clean it up.

In the UK we have Beachwatch, a national scheme for beach cleaning. But on a global scale, much gets caught up in ocean currents and accumulates. Over time, this does break down through mechanical action of winds and waves, but also through UV degradation.

The Ocean Cleanup group published a feasibility study outlining the problem and solutions to this. A team of engineers have proposed a strategy of floating barriers and a platform to extract the plastic from the ocean. This comes with a bold statement of scale, 7,900 times faster, 33 times cheaper than conventional methods. They are working towards a large-scale pilot to operate within the next three or four years.

The team of scientists and engineers include those doing computational fluid dynamics, modelling and simulations of the booms. This is applied across many science and engineering disciplines but is a fundamental part of the chemical engineering skill set.

The project also proposes to process the plastic; reusing the materials. The recycling of mixed plastics that undoubtedly will contain contaminants can be costly if cleaning and separation are required.

Chemical engineers are already working in the area of mixed waste plastic. Some processes involve cleaning and mechanical processing to produce composite materials. Others use chemical recycling through hydrolysis and pyrolysis. These two methods allow recovery of chemicals and fuels from the waste plastic.

Examples of this work are present in many areas of the world. Cynar plc installed its first full scale pyrolysis plant in Ireland in 2008. The original work involved SITA UK, but this is global and SITA Australia is also working on this.

Another example of this is Recycling Technologies Ltd who recognises the environmental and economic case for this work. This spin-off company involves many chemical engineers and makes fuel from mixed plastic waste.

In the future, every single person on the planet should have a duty of care to their environment. Each one of us can inflict needless ham. Thankfully, with the careful disposal of waste like plastic, chemical engineers have the skills and knowledge to turn environmental dangers into valuable and re-usable commodities.