By Martin Schleef, Senior Engineer, Process Systems Group Leader, M+W Germany GmbH; Detlef Worf, Senior Engineer, Process Systems Group, M+W Germany GmbH; Rolf Bartels, Senior Engineer, Process Systems Group, M+W Germany GmbH; Mila Kostieva, Project Engineer, Production Environments Group, M+W Germany GmbH; Mariska de Wild-Scholten, Member of the Research Staff, ECN Solar Energy
This article provides an overview of the typical waste water treatment methods for crystalline silicon solar cell production. Firstly, a short description is provided of the main process steps of photovoltaic production and the types of waste water generated during these steps. Secondly, the typical waste water treatment methods of hydrogen fluoride (HF) precipitation and neutralization are presented. Furthermore, some options for the reuse of rinse water are discussed and several guidelines for the design of waste water treatment systems are given. Finally, the relative environmental impact of the waste water treatment compared to the emissions of the whole fab is presented using the life-cycle assessment (LCA) methodology.