On the directions of the principal bench of the National Green Tribunal, the Central Pollution Control Board (CPCB) has brought out guidelines to manage plastic waste generated from thermoset plastic, that cannot be remoulded or recycled. This is the first time that the pollution watchdog has drafted guidelines for managing this type of waste generated from the auto, electrical and electronics, building and construction sectors and domestic use. This material is used in cars, trucks, trains, domestic electrical products, fuses, coffee machines toasters and even sanitary ware.
Thermoset plastic when cured by heat or other methods changes into an insoluble product. Once the product made of thermoset plastic is discarded, it accumulates and degrades the environment, as it cannot be recycled. After the NGT directed them to look at guidelines for managing them, CPCB constituted a committee comprising of officials from environment ministry, Central Institute of Plastics Engineering and Technology, Bureau of Indian Standards, IIT Delhi and Associated Cement Company to frame scientific and best ways to manage thermoset plastic.
The committee found that not a single system exists at present wherein municipal bodies collect, segregate and transport all kind of plastic waste including thermoset plastic. To correct this, it has recommended that municipal bodies should seek assistance of producers a system should be built one year from the date of final publication of the official notification. To minimize the waste generation, the committee has also said that alternatives to thermoset, polycarbonate should be identified that could also be recyclable.
Further studies showed that co-processing of thermoset polymer waste in cement plants is a more environmentally friendly and sustainable method of disposal compared to land filling and incineration. This reduces emissions and leaves no residue after treatment. In this method, the plastic waste is used as raw material to recover energy and material from them. "Due to high temperature and long residence time in cement kiln, all types of wastes can be effectively disposed without any harmful emissions," the CPCB report on guidelines said. Trials of using thermoset plastic waste in cement kilns have been carried out in ACC's Madukkarai Cement plant in Tamil Nadu.
According to the report, the trial worked well and CPCB allowed the company to use the waste for processing on a regular basis.
CPCB has also said in its recommendations that in future, while issuing consent to operate permissions to cement plants, conditions can be put into use thermoset plastic waste for co-processing and such cement plants can be given incentives.
