"The best solution would be recycling as much plastic waste as you can," George Huber, professor of chemical and biological engineering, University of Wisconsin-Madison, the U.S., said when asked about possible options for Vietnam.

In the U.S., there are hundreds of material recovery facilities (MRFs) where people can leave everything that can be recycled, he said.

Either workers or robots sort the materials, including plastic, and palletize them and they are later sold to secondary recycling people who do further sorting and turn them into pellets.

There is a whole market for these pellets for making new products.

For instance, there is a company called Placon that produces food and medical packaging and other types of plastic from MRFs.

They buy recycled PET bottles and thermoform them, thus keeping over one billion PET bottles out of landfills each year.

Huber said: "This is called closed-loop recycling. They produce the ecostar plastic which is a recycled plastic."

Technologies used by companies like Placon are pretty similar, usually involving floating. They put plastics in water, and some float while others sink. They then purify the floating plastic and grind it to make pellets. There are many things that can be made from recycled plastic.

Highlighting another good recycling model, Professor Michael Braungart, founder of Internationale Umweltforschung GmbH, an environmental research institution based in Hamburg, Germany, said the U.S.’s Envision Plastics is the only company in the world that makes polypropylene approved by the U.S. Food and Drug Administration for making food-grade packaging.

In Italy, a company called Aquafil has reprocessed around 15,000 tons of nylon from driftnets in oceans to make clothing, carpets and other products, he said.

Associate Professor Duong Hai Minh of the department of mechanical engineering, National University of Singapore, said Vietnam could consider the option of converting plastic waste into aerogels, which are used in billion-dollar engineering applications such as heat and sound insulation, oil spill cleaning, fruit preservation, air pollution filtering, personal care products, and wastewater treatment.

He said this is a cost-effective and eco-friendly method since no toxic solvent is used or discharged into the environment, and it requires 70 percent less energy.

Aerogels can be reused and recycled.

Moreover, the technology can also be used on a range of wastes like paper, old clothes, rubber tires, fly ash, metal, and agricultural and food wastes.

For the first time aerogels have been made from PET, the same plastic used to make water and soft drink bottles.

"The technology might be available in April 2021," Minh said.

He said there are various options for Vietnam for dealing with plastic that are used in Singapore such as incinerating or converting it into low-value products (chair, bag, umbrella, etc).

In incineration plants, waste is burned and the smoke quality is controlled to ensure it does not damage the air quality. The ash is used in construction as a less toxic option.

Huber said some plastics like pure PET and pure PE could be recycled but most could not, and there are also losses in the plastic recycling process. So any plastic recycling needs to be combined with long-term plans to deal with plastic wastes like incineration and landfills (where minimal leakage occurs), he said.

When incinerating, heat and energy could be recovered, then plastic does not leak into the environment and could be controlled in one location, he said.

There are companies in the U.S. burning plastic waste to generate electricity and heat and generating small volumes of ash that eventually go into landfills, he said.

"I think landfilling should be the less preferred option."

Professor Carl Redshaw of the University of Hull, the U.K., said a number of technologies are being trialed for converting plastic waste into high-value useful products.

For instance, radiation-induced degradation, microbes, metal-based nanoparticles, and activated carbon could all turn waste into liquid fuel, pyrolysis (thermal degradation) could turn plastics into energy while the use of photo-catalysis (use of light to drive a reaction) has shown that even non-degradable plastics such as polyethylene could be converted into other useful materials, he said.

A recent report in a scientific journal illustrated how discarded drinking cups could be converted into other useful chemicals though most of these technologies are at an embryonic stage and require more investment, he added.

How to apply in Vietnam

Huber said the first step for Vietnam to recycle plastic wastes is to be able to sort them depending on their original components. Some would have to go to landfills or be burned, while the infrastructure to collect waste plastics has to be developed, he said.

If the country wants to have a similar system as the U.S., it needs to have secondary recyclers who could turn plastic into pellets and make products from them, he pointed out.

But all these involve a very large initial cost, and it takes five to eight years to recoup it before the operation becomes profitable, he said.

The legal framework is crucial, he said.

In the U.S., many material recovery facilities are owned by municipalities and states make laws. It is illegal to send certain kinds of plastics to landfills.

As for the burning option, Huber said companies need to have air pollution control equipment to make sure the smoke does not have any dangerous chemicals.

It is important that these facilities are designed in a way to minimize air pollution, he said.

In the U.S., the Environmental Protection Agency sets regulations.

Rules to prevent air pollution are vital, especially in developing countries, Huber said.

Dr Alex Ibhadon, reader in catalysis and reactor engineering, University of Hull, the U.K., said society needs plastics to create products and jobs.

Southeast Asia in general is producing more and more plastics while Europe is producing less and less, and it is not easy for Vietnam to close thousands of companies in the plastic industry, he pointed out.

Vietnamese people should reuse over and over again the plastics they already have, he said.

In the U.K., supermarkets need to produce reusable carrier bags and some charge customers for carrier bags as an encouragement to re-use, something Vietnam as a country could learn from, he said.

Experts said another way to reduce the plastics is by using new materials.

Braungart said Vietnam could learn from Novamont, an Italian company that makes plastics from starch for single use that easily degrades and is good for the environment.

It makes bioplastics from starches, cellulose, vegetable oils, and their combinations, and ideally Vietnam should decide that all the plastics ending up in the environment needs to be biodegradable, he said.

Redshaw said he and his colleagues produce polymers from renewable resources such as corn starch.

He said there are now a number of biodegradable polymers on the market like Sigma Aldrich’s poly (lactide), poly (glycolide) and their copolymers, and a number of biodegradable natural polymers.

A number of U.K. small enterprises have ongoing projects that they hope to bring to the market soon, he said.

"No doubt companies in countries such as Vietnam are thinking along these lines too."

Vietnam needs to offer large incentives to entice the industrial sector, specifically the producers of petroleum-derived plastics, to invest in infrastructure that would allow them to make the switch to some of the greener alternatives, he said.

There is also a need to change people’s mindset on how to use plastic, and this could be achieved by good communication and having efficient protocols in place, he said.

Emphasizing the significance of the legal framework, Dr Ibhadon said the Vietnamese government should have a policy that makes plastic recycling a legally enforceable requirement and set up recycling centers throughout the country for various types of plastics.

It must take the lead in reducing plastic use and enforce recycling as a partnership between itself, plastic producers and consumers, he added.