by Ashis Sinha
A team of IIT (ISM) Environmental Science and Engineering Department researchers developed a technique to remove fine particles and heavy metals from the coal washeries effluents.
In their ongoing research, they found that bio coagulants like Mustard, Moringa Oleifera, and others can remove high loads of suspended solids like coal fines, shale, slate, clay minerals, and other impurities from coal washery effluents.
Bio Coagulant can also be used to remove undesirable wastes from coal washery effluents, avoiding issues like post-processing sludge and environmental leaching, the research suggests.
The findings of research being carried out under the leadership of Sukha Ranjan Samadder, Associate Professor of Environmental Science Engineering Department, as per a Coal India Limited funded project worth Rs 54.87 lakh also suggested that the use of Bio Coagulant in place of chemicals offer a cost-effective, easily available, eco-friendly, nonhazardous, and biodegradable substitute which produces less volume of sludge, informed Rajni Singh Dean, Media & Branding IIT-ISM, Dhanbad.
Professor Samadder, who began the two year research in March, 2022 as Principal Investigator along with two Co Principal Investigators, Kumar Rajeev, Chief Manager (Mining), Head of Environment Department of BCCL; Dr Amartanshu Srivastava, Deputy Manager at Environment Department of BCCL besides Khalid Ansari, Research Associate at his department said, “The coal fines which have a tendency to wash away will be recovered using Bio Coagulant as the Calorific Value of these Coal Fines will be improved as Bio Coagulant itself have some calorific value.
“The use of Bio coagulant also helps to improve the quality of effluent water by removing the coal fines and other contaminants,” said Samadder and added that the same water after treatment can be recirculated, improving washing efficiency as water is cleaner.
Explaining the technicalities, Samadder said, “Fines having a size of less than 0.42 mm are generally responsible for forming slurry, and if this fine is discharged untreated, it will lead to deterioration of quality of bother underground water as well as the quality of natural water bodies.”
“Heavy metals present in the coal washery effluents are also a cause of concern as they get accumulated in water, soil sediments and living organisms; therefore, no effluent is allowed to be discharged outside the washery premises as per present environmental policies” further said Samadder and added the recovery of coal fines from the effluents still pose a lot of challenges. He further said that the treatment of coal washery effluents in the Indian Subcontinent is traditionally carried out with the help of conventional radial thickness, which works on the principle of sedimentation, and added that less effort has been made in the field of efficient effluent treatment and trapping of fine particles.
“Generally flocculation technology is applied in most coal preparation plants to recover fine particles from the tailings of coal washing operations” and added that it is accomplished through the use of inorganic salts, polymeric flocculant, or both depending upon physical and chemical characteristics of fine particles present in the suspended and dissolved states.
Dean (Media & Branding)
Phone: (0326) 2235447