A settling grid separator apparatus and method of use which provides deep dehydration of high flow rate sludge in an environmentally friendly and energy efficient manner. The apparatus and method comprise and utilize an efficient mixing of the sludge with a flocculating agent or polymer solution, and sludge flow quieting techniques to reduce disturbances and promote flocculation of clustered solids. Free surface liquid rejection, a series of traps, and pressurized filtering utilize gravimetric, hydrometric, and densimetric techniques to separate liquid from suspended solids. Gravitational forces are utilized throughout the apparatus and method to promote separation of higher density solids from the lower density liquid carrier. Upon separation, solids with a minimal liquid content are controllably discharged for proper disposal or recycling.