Filtrate is the waste that has been discharge in vacuum ceramic filters through the waste stream.  During cake washing, a wash liquid is sprayed on the cake solids to remove impurities or additional filtrate. The filtrate goes into filtrate tank and is drained through a discharge system. However, the filtrate is recyclable and has low suspended solid content. Thus, it can be recycled through the system without further treatment. Filtrate is used to flush the disc during back flow washing to clean the micro-porous structure and remove any residual cake.