Waste an unexpected hero of global warming

As the world scrambles to fight the effects of global warming and reduce carbon emissions, plastic waste can prove a valuable ally in more ways than one. MARISKA MORRIS investigates

Although plastic has received a bad reputation in the past few years, the durable, recyclable material offers many benefits. According to the World Economic Forum (WEF), it has played an invaluable role in reducing carbon emissions.

“Since 2004, for example, automobile fuel efficiency has climbed 29 percent while related greenhouse gas emissions have fallen by 23 percent. Plastics have played a huge part in that success by providing lightweight and durable alternatives to heavier materials such as steel,” the organisation states.

However, much of plastic’s potential is lost and overshadowed by the environmental impacts of unrecycled plastic.

What is lost

The WEF estimates that the value of global plastic waste ranges between US$ 80 billion (R1,16 trillion) and US$ 120 billion (R1,74 trillion). In addition, the material is the cause of a global environmental crisis. It is estimated that eight-million tonnes of plastic spills into the world’s oceans each year, which suffocates the wildlife and contaminates food sources.

By recycling as little as one tonne, it’s possible to reduce CO₂ emissions by between 1,1 and three tonnes.  Oil is also used in the manufacture of plastic. An estimated six percent of global oil consumption is used in all plastic production – the same percentage consumed by the global aviation sector.

The WEF explains: “If the current strong growth of plastics usage continues as expected, the plastics sector will account for 20 percent of total oil consumption and 15 percent of the global annual carbon budget by 2050.” Recovering plastic waste is thus vital to the environment, but also holds incredible financial opportunities.

South African plastic consumption

Although a small player in the plastic production globally, South Africa still consumes roughly 1,5-million tonnes of plastic annually. Fortunately, the country is a forerunner when it comes to recycling plastic, with 46,3 percent of all plastic products  recycled in 2018, according to Plastics SA.

The biggest contributors to the success of recycling in the country are the informal waste pickers who, according to the Department of Environmental Affairs, intercept 68 percent of recyclables.

Unsurprisingly, the packaging industry is the biggest consumer of plastic at 53 percent, according to the department’s estimates. It is followed by the building and construction industry at 13 percent.

While the packaging industry investigates biodegradable alternatives to reduce plastic, one construction company plans to increase its plastic use in the best possible way – by intercepting plastic waste.

PlastiBrick

In 2016, Kekeletso Tsiloane prototyped the first PlastiBrick – an invention that uses recycled plastic to manufacture
bricks that are strong, durable, fire-retardant and environmentally friendly. The production process requires only melted plastic and sand.

“There is no water used in the production of PlastiBrick; thus, along with reducing plastic waste, it also saves water,” Tsiloane explains. “These environmentally friendly bricks are denser than normal bricks and have a lower rate of water absorption to give buildings a longer lifespan.”

As the brick is manufactured from plastic, it also provides some insulation to make buildings energy efficient. These bricks have also been tested and approved by the South African Bureau of Standards.

Ramtsilo Manufacturing and Construction sells interlocking and Bevil pavers, cement stock and maxi bricks manufactured from plastic. The products have been sold to small-scale contractors. The construction industry worldwide is pushing for more environmentally friendly solutions.

Greener buildings

A Swedish construction company is placing plastic spherical voids between concrete slabs to reduce the amount of concrete used and, thus, the carbon emissions produced (see the SHEQ MANAGEMENT HANDBOOK 2020 for more information). Cement is the source of eight percent of global CO₂ emissions – more than jet fuel!

A group of scientists at the University of Colorado Boulder, in the United States (US), are taking it a step further with “living concrete”, which consists of sand, gel and bacteria. It is more environmentally friendly than concrete – the second most-consumed material globally after water.

Sand and hydrogel were used in the experiments to build a structure in which cyanobacteria can grow. These green microbes live in water and manufacture their own food. By using living organisms, the building material is self-healing. When a lab-grown brick was split, it grew into two complete bricks with the help of extra sand, hydrogel and nutrients.

While there are still some drawbacks, these living materials can also help fight global warming by absorbing carbon dioxide from the air. This is not the only innovation that looks to fighting carbon emissions, although the other alternative is more surprising.

Looking to the past

Experts are suggesting wood as the building material of the future, according to Fast Company. Although the switch to this age-old material will require strict, sustainable forest management, it does have the opportunity to store carbon.

According to experts at the Potsdam Institute for Climate Impact Research in Germany, timber buildings act as carbon sinks in a similar way to forests by capturing carbon emissions.

Kristin Toussaint writes for Fast Company: “A five-story residential building made with laminated timber can store up to 180 kg of carbon per square metre – three-times more than natural forests with high carbon density.”

Another benefit of reverting to wood as a building material, is that the waste can be used to manufacture paper or insulation, thanks to the innovation for the GO Lab Timber Pure Technologies plant in New York, US. The insulation can be recycled, is biodegradable and its production doesn’t expand the carbon footprint.