What is a filter press and how does it work? A filter press is one of the oldest and most trusted pieces of dewatering equipment. They’re used for wastewater treatment across a variety of industries and applications. A filter press works by separating out solids from liquids, removing impurities, and suspended solids from industrial wastewater. This allows plant managers to easily handle and dispose of waste while returning clean water to their systems. Want to learn how the technology or filtration equipment works or how it could help your operation? In this Water Facts, we'll examine these details further.