A zero discharge system consists of three or four linear motion shale shakers to treat mud to separate the cuttings from drilling fluids. The drilling cuttings are discharged from shale shaker, desander, desilter, decanter centrifuge to a screw conveyor to transfer the cuttings to vertical cuttings dryer ( oil based drilling cuttings) or high G drying shaker ( water based drilling cuttings).
The vertical cuttings dryer is used to recover the oil from drilling cuttings. The discharged solids with oil content below 5% will be collected by screw conveyor for disposal or landfill directly or be sent to Thermal desorption unit for further heating and reduce the oil content to meet the environmental protection regulation.
The recovered oil fluids will be collected by fluids holding tank. One submersible slurry pump or progressive displacement pump transfer the fluids to decanter centrifuge to separate the colloidal particle solids from the drilling fluids. The fluids is returned to the solids control system by a transfer pump.
The water based drilling cuttings are treated by high G drying shaker through shaker screens, the discharged solids together with the solids discharged from decanter centrifuge are collected by screw conveyor and transfer to cuttings solidification unit, to mix with lime and absorber, the solidification of waste allowed the transportation and disposal of the solids without secondary containment, and converts hydrologic sensitive liquid and semi-liquids waste in a physical form which can be storage safely.
During the whole processing, the drilling waste treatment is in a closed loop without requiring dig a waste pit. Zero discharge system including shale shaker, desander, desilter, mud cleaner, centrifugal pump, decanter centrifuge, high G drying shaker, vertical cuttings dryer, waste centrifuge and feeding pump, screw conveyor, etc. If you need a zero discharge system for drilling rig, pls contact with GN solids control.