Sensors to stop plastic waste may sound like a tall claim – however, the technology is a scientific reality now, changing the waste management sector.
Until a century or two ago, waste segregation was not an issue. With the advent of plastics and material sciences revolution, and an incessant growth of the packaging industry, segregation of wastes has never been so complicated. Landfills are overflowing, posing a serious threat to the surrounding ecosystems with a myriad of different materials. Therefore, segregation of wastes is essential to protect environments by way of recycling and reusing. However, segregation becomes a gargantuan task with the innumerable kinds of wastes generated daily globally.
Though segregating wastes is becoming an industry to promote employment, the occupational hazards in physically working at the waste dumping sites or even at source are enormous. To overcome these hurdles, technology has been used since the 1990s. The specific properties of the wastes are used to segregate them using various technologies - a few employ particle separators, electromagnetic properties, and spectroscopy (using NIR and X-rays radiation to detect the type of material).
The light absorption spectroscopy of plastics was discovered in the range of 300 to 3000 nm, opening up the possibility of optical sensing of plastics. All kinds of plastics had a peak value near 1700 nm. IDEC Corporation from Canada developed the world’s first technology capable of detecting three different types of plastics based on their unique absorption characteristics.
RoCycle for Plastic Detection
Infra-red spectroscopy is conventionally used to identify plastics and other organic materials. Based on absorptions at different wavelengths, produced by Indium Gallium Arsenic Phosphorous (InGaAsP) semiconductor laser diodes (LDs) and receptors, different plastics are distinguished: PET (polyethyleneterephthalate, used in plastic bottles), PVC (polyvinyl chloride, used in a range of industrial and domestic products), HDPE (high density polyethylene, used in piping, membranes and bottles), Low Density Polyethylene (LDPE, used to make containers and plastic bags), Polycarbonate (PC, used in shatterproof windows, lightweight eye-lenses), polypropylene (PP, used in various consumer products), and polystyrene (PS, used in disposable plastics). MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) has developed a robotic system, “RoCycle”, built on a set of sensors that differentiates between hard and soft objects with 78% accuracy, detecting if an object is paper, metal or plastic (2019).
Drawbacks of using sensors to avoid plastic wastes are initial investment which is quite expensive, and all sectors of the economy, especially in a developing country, may not be able to afford it.
Stopping Plastic Waste Using Sensor Technology
How does the sensor technology stop plastic waste? Places where plastic use and misuse is banned, sensors may help monitor and regulate the standards. Sensors can make the task easy, efficient and time-saving. It may help in penalizing the violators. This step would defect more people from using plastics. These sensors can also be used to police illegal use of plastics, especially around protected ecosystems, which may minimize and deter use of plastics.
Sensor based sorting is mainly used in mining, recycling and food processing sectors. With these sensor based technologies to sort plastics, a dull, dirty, time-consuming, and expensive job carried out by people can be automated entirely. This helps the recycle and reuse sector.
The idea is ‘to reduce back-end cost of recycling, ultimately incentivizing more cities and countries’ to develop their own recycling programs. Especially in developing nations, these technologies may revolutionize the waste management sector and stop plastic waste.