Tread on greener highways — say goodbye to the pyrolysis process

Late January, The Guardian carried a column by well-known British environmentalist, author and activist, George Monbiot. The piece revealed that the UK was sending massive shipments of discarded tyres to India instead of recycling them on its own soil.

The exports were reaching Indian factory units that turned them into tyre-derived fuel, mostly tyre pyrolysis oil which is used to reprocess tyres into fuel gas, solid residue (char) and low-grade carbon black. Monbiot’s research showed that there was hardly any check kept by the UK government to ensure that its discarded export reached legal processing units and was not adding to the already disastrous air quality in our cities and towns. For that matter, nor is there any monitoring of such imports on Indian soil.

We also know that there is virtually no track on where discarded tyres reach — there is no centralised management policy for end of life tyres (ELT) in the country, despite draft guidelines on waste tyre management rules being drawn in 2017. Neither have we been able to promote ‘back to basics’ for tyres and encourage reuse of the product by retreading it or regrooving it for a second use.

“Retreading was a thing of the past which is no longer done in the metros by the organised market. We collect the old tyres into a heap and wait for the recycler to come and collect them,” says a prominent tyre dealer in Bikaji Cama Place, Delhi. He also admits that no tyre company reclaims used tyres or feels that the ‘polluter pays’ principle’ applies to it. “”There is no such legislation, so why should they do it? Yes, sometimes to increase sales they offer rebuying in their advertising campaigns, but there is no seriousness on this count.”

The way forward

So, what can be done with used tyres which goes beyond the pyrolysis process and the responsibility of the manufacturer? According to a report that was done by Environmental Research and Action Group, Chintan, which ought to have been given due weightage, the best way forward would be to formalise and widen the use of crumb rubber modified bitumen (CRMB) for road construction in the country. By this we can reduce the import of bitumen by 12 to 14 per cent, while utilising waste tyres in an environment friendly manner. According to estimates, between 6 and 8 lakh tonnes of bitumen is being imported annually into the country.

Many advantages

The use of CRMB, recommended by the Union Ministry of Road Transport and Highways, but not made mandatory, has significant pluses.

Apart from lowering the cost per km of road laying, it improves pavement performance, gives better riding quality and durability.

The other advantages listed by the authorities include the road being less susceptible to temperature variations, higher resistance to deformation, better properties of age resistance, delay of cracking and reflective cracking, better adhesion between the aggregate and binder and overall improved performance in extreme climatic and heavy traffic conditions.

Given the wide-ranging advantages, the Chintan report recommended that highway builders should be given a clear directive to increase the use of CRMB and bring it to the level of 35-40 per cent of the total bitumen consumption, which, at present, stands at 2-3 per cent. The environmental group’s data showed that the growth of end of life tyres (ELTs) and roadways synchronised with each other making use of discarded tyres as a good means of achieving a circular economy.

However, after a flurry of activity in 2017, the government seems to have gone silent on the issue of switching to CRMB. Instead, used tyres go through the pyrolysis process which adds to air pollution if it is not closely monitored. Currently, it is widely being employed by the unregulated informal sector. We could make better use of ELTs with monitoring, regulation and the will to build a circular economy.

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