Joyabrata Mal was born in 1987 in Kolkata, India. Joy did his bachelor (B.Tech) in Biotechnology at West Bengal University of Technology. He later joined the Indian Institute of Technology, Guwahati, India for his master (M.Tech) of Technology degree in Biotechnology. During this degree, he did his specialization in Environment Biotechnology and worked on synthesis of biohydrogen from carbon monooxide. Joy got admitted into Erasmus Mundus Joint Doctorate Program on Environment Technologies for Contaminated Solids, Soils and Sediments (ETeCoS3) and started as PhD Fellow at UNESCO-IHE from October 2013. As part of program, he also carried out his PhD research at Université Paris-Est. and worked at University of Limoges under a short term scientific mission (STSM, COST Action ES1302). His research was mainly focused on developing novel methods for chalcogens (selenium and tellurium) bioremediation, bioreduction and recovery. He is currently a postdoctoral fellow in University of California Berkeley and working on selenium biogeochemistry.

• 1 General introduction2 Literature review3 Biological removal of selenate and ammonium by activated sludge in a sequencing batch reactor4 Effect of heavy metal co-contaminants on selenite bioreduction by anaerobic granular sludge5 Biosynthesis of CdSe nanoparticles by anaerobic granular sludge6 Modification of extracellular polymeric substances (EPS) induced by cadmium and selenium enrichment of an anaerobic granular sludge used for synthesis of cadmium selenide nanoparticles7 Continuous removal and recovery of tellurium in an upflow anaerobic granular sludge bed (UASB) reactor8 A comparison of fate and toxicity of selenite, biogenically and chemically synthesized selenium nanoparticles to the Zebrafish (Danio rerio) embryogenesis9 Discussion, conclusions and perspectives