Dr. Pardeep Singh is presently working as an Assistant professor (Department of Environmental Science, PGDAV College, University of Delhi, New Delhi, India). He obtained his master's degree from the Department of Environmental Science Banaras Hindu University, Varanasi India in 2011. He obtained his doctorate from the Indian Institute of Technology (Banaras Hindu University) Varanasi in the year 2017. The area of his doctoral research is the degradation of organic pollutants through various indigenous isolated microbes and by using various types of photocatalytic. He has published more than 65 papers in the international journals in the fields of waste management. Mika Sillanpää is a Distinguished Professor in the Faculty of Engineering and the Built Environment, Department of Chemical Engineering Technology, University of Johannesburg, South Africa. His research work centers on chemical treatment in environmental engineering and environmental monitoring and analysis. More specifically, he has worked extensively with adsorption, photocatalysis, electrochemical treatment, membrane biological processes and advanced oxidation processes as well as ion mobility spectrometry, chromatographic methods, electrochemical sensor development and real-time monitoring.