**Acknowledgements**

The author would like to dedicate and acknowledge the contribution to this study of Professor Fernando Valenzuela Lozano. For his invaluable friendship, his continued mentorship and all the technical and inspiring discussions across many years already, regarding hydrometallurgy and especially wastewater treatment of AMD. I would like to specially acknowledge the helpful input of Dr. Marcelo Sepulveda and Mr. Cesar Arredondo to this work. In addition, many thanks to Mr. Mario Solari and Mr. Thomas Ph. Chirino for providing pictures from industrial case scenarios and real-life portraits which had significantly increased the value of this manuscript. And, last but not least many thanks to Ms. Ana Maria Rojo for her assistance and good ideas to put together this chapter.
