Filtration　proceeds　in　a　filter　press　primarily　in　two　stages　-　filtration　and　filter　consolidation.　Filter　consolidation　conforming　to　the　so-called　Terzaghi＇s　model　in　soil　mechanics　is　the　major　concern　in　the　present　paper.　A　partial　differential　equation　treating　filter　consolidatin　as　a　three-dimensional　model　is　given.　It　is　demonstrated　that　the　above　equation　can　be　applied　to　constant　pressure　filter　consolidation　in　a　filter　press.　Results　of　high　accuracy　are　claimed.