Most of the plastics used in South Africa are nonbiodegradable, especially in the packaging industry, and end up in landfills, posing environmental threats and health concerns, Council for Scientific and Industrial Research (CSIR) polymer modification group leader Dr Avashnee Chetty says.

Unpacking various technologies that the CSIR is developing at the CSIR Tech Day, which took place in Pretoria last month, she noted that there was a need to replace the synthetic polymers that are petroleum based, with natural polymers, in plastics.

“We have developed a biopolymer material that we have modified with a natural polymer and it is 100% biodegradable,” she stated.

“We are using a polymer from biomass, which we beneficiate, to develop a plastic sheet that can be used in packaging, as well as disposable material for diagnostic devices. We are particularly targeting single-use applications,” she said.

Another technology that the CSIR is developing, together with the Agricultural Research Council (ARC), is a membrane and method for the preservation of fresh produce.

Chetty pointed out that most of the decay of fresh produce occurs during post-harvest, after the fruit leaves the farmer to be handled, packaged, transported and stored.

Typically, the use of pesticides and fungicides are prohibited during post-harvest control, especially in the organic produce market, she noted.

“There is a need to replace these chemical pesticides with biological control agents and the technology that we are developing, together with the ARC, uses essential oils as a natural biofumigant to control the decay of post-harvest fresh produce,” she said.

She explained that the novel controlled release sheets are infused with major constituents of essential oils of lime, lemon and lemongrass that can replace the use of chemical fungicides.

“This technology involves the incorporation and infusion of a mixture of those major constituents into a multilayer polymer sheet that permits a controlled release of its volatiles in combination with either modified atmosphere packaging or cold storage technologies,” she said.

Chetty added that the project’s objective was to provide a controlled release composition comprising a polymer sheet onto which a volatile, which is as effective as a fumigant, has been absorbed.

“Currently, we are using sulphur dioxide based sheets, which are chemical fumigants that could carry residual toxins that the consumer is exposed to. There is a need to replace these fumigants with something that is safe, environment-friendly and low-cost.”

She noted that the CSIR was currently doing fields trials with the ARC and is looking for a commercialisation partner to take this technology to market.

The CSIR, meanwhile, is also working on a water purification treatment system.

Chetty noted that a lot of South Africa’s water purification technology was imported, such as membrane based reverse osmosis technologies and desalination technologies, and that the capital expenditure for these products was very high.

She noted that the CSIR has developed an absorbent technology comprising beads using granular activated carbon to remove contaminants from water.

“We have scaled up the technology and we are in the phase where we need to take it to the field. We are looking mainly at the removal of nitrate and phosphates,” she noted.

Chetty added that industry has a lot of waste water and that there is a need to have on-site technology for treating their waste and recycling the water.

“South Africa is water stressed and water quality will be a major issue going forward,” she said.