Sulphur Current Affairs
Scientists from CSIR-Institute of Minerals and Materials Technology (CSIR-IMMT) have found four bacterial strains that remove sulphur from fossil fuels such as petroleum and coal. Sulphur is one of the major pollutants emitted during the combustion of fossil fuels.
The four bacterial strains are Rhodococcus rhodochrous, Arthrobacter sulfureou, Gordonia rubropertinita and Rhodococcus erythropolis. They use dibenzothiophene, an organic sulphur compound which is major contaminant of fossil fuel as energy source thereby getting rid of sulphur.
They were selected from 10 bacterial strains with dsz genes to find novel bacterial strains that can selectively eliminate this organic sulphur. The dsz genes are central to sustainable bio-desulfurization (a non-invasive process of sulfur removal from fuels by means of living organisms). The selected bacteria were grown in medium supplemented with dibenzothiophene and other nutrients required for growth.
It was found that four bacteria were able to use almost 99% of sulphur compound in just 10 days. Researchers were also able to identify process of bio-desulfurization of these bacterial strains through specific pathway (4-S pathway).
The process of bio-desulfurization using these four bacterial strains is also eco-friendly and economical. These bacterial strains can be potentially used on commercial scale for removal of sulphur from fossil fuels on commercial scale.
Delhi became the first city in India to supply ultra-clean Bharat Stage (BS) VI grade fuel (both petrol and diesel) with an aim to combat the rising levels of air pollution in Delhi-NCR region. State-owned oil firms have started supplying the BS-VI fuel (equivalent to fuel meeting Euro-VI emission norm) at all their 391 petrol pumps in NCT.
Other cities in NCR like Noida, Gurugram, Ghaziabad and Faridabad as well as other 13 major cities, including Mumbai, Chennai, Bengaluru, Hyderabad and Pune will roll-out cleaner BS-VI grade fuel from January 1 2019. However, BS-VI fuel will be rolled out in rest of the country by April 2020. By switching to BS-VI, India will join league of US, Japan and European Union, which follow Euro Stage VI emission norms.
The Union Government in October 2016 had decided to skip one stage and migrate to BS-VI directly from BS-IV from April 2020 to fight the growing pollution. The deadline for it in Delhi was brought forward to 2018 due to higher level of pollution i.e. thick toxic smog faced in winter season. It was part of concerted efforts of Government to reduce vehicular emissions and improve fuel efficiency with an aim to reduce carbon footprints and keep environment healthy.
Benefits of BS-IV fuel
The major difference in standards between the existing BS-IV and new BS-VI auto fuel norms is presence of sulphur. BS-IV fuels contain 50 parts per million (ppm) sulphur, while BS-V and BS-VI grade fuel will have 10 ppm sulphur. Thus, newly introduced BS VI fuel is estimated to reduce amount of sulphur released by 80%. It will also bring down the emission of NOx (nitrogen oxides) from diesel cars by nearly 70 % and 25% from cars with petrol engines. It will also bring down cancer causing particulate matter emissions from diesel engine cars by phenomenal 80%.