A modularly segmented apparatus for precise borehole pressure control, removing waste from borehole fluid, and recirculating the cleaned borehole fluid includes a pressure control section, a gas separator section, and a waste management section. In the pressure control section, a pressure manifold interconnects a plurality of chokes. A plurality of valves are used to direct the contaminated fluid through one of the chokes, which maintains a precise and predetermined pressure in the system. The manifold, chokes, and valves are mounted on a skid for easy transport. In the gas separator section, a gas separator is used to remove a majority of the gases present in the contaminated borehole fluid. In the waste management section, a vibratory separator removes large solid contaminants from the degassed fluid. The solids are directed to a solids collection container for further treatment or disposal. The fluid is directed to a first pit, which may be one partitioned are of a larger collection tank. Fluid from the first pit is directed to a degasser which removes additional gases in the fluid and directs the fluid to a second pit. Fluid from the second pit is directed to a desilter, which removes additional solids and directs the fluid to a third pit. The solids from the desilter are directed to the solids collection container. Fluid from the third pit is directed to active rig pumps for recirculation into the borehole.