André dos Santos holds a bachelor's degree in Civil Engineering from the Federal University of Ceará, Brazil (1998) and a Ph.D. in Environmental Sciences from Wageningen University, The Netherlands (2005). He is a Full/Titular Professor at the Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Brazil. He has worked for 25 years in the field of environmental technology, and currently is editor-in-chief of two prestigious Brazilian journals, associate editor of the Journal of Environmental Chemical Engineering (Elsevier) and Journal of Hazardous, Toxic, and Radioactive Waste (ASCE), and ad-hoc of more than forty journals. He has already received many professional and scientific prizes, such as Top-25 most cited articles from Bioresource Technology from 2007 - 2010, Elsevier (2010). Renato Carrhá Leitão holds a bachelor's degree in Civil Engineering from the Federal University of Ceará, Brazil (1988) and a Ph.D.

in Environmental Sciences from Wageningen University, The Netherlands (2004). From 1991 to 2000 he worked at the Water Resources Office of Ceará State as design analyst; at the Meteorological and Water Resource Foundation of Ceará State as environmental engineer, at the private firm Gaia Environmental Consulting S/A as managing partner and CEO, and finally at the private firm Engesoft Engineering and Consulting S/A as project/design manager. Since 2016, he is Senior Researcher at the Brazilian Agricultural Research Corporation (Embrapa) and Permanent Professor at the Post Graduate Program in Natural Science, State University of Ceara, Brazil, where he coordinates investigation on environmental management, agro-industrial waste and wastewater treatment and reuse, anaerobic digestion of agro-industrial waste(water) for biogas, hydrogen and organic acids production, and on process development for separation of high added-value product from lignocellulosic biomass.