A process for treating drilling fluids which are used during the process of drilling for fossil fuels includes providing a drilling fluid having a continuous hydrocarbon phase, a discontinuous aqueous phase, and a discontinuous solid phase, a polymer solution, at least one coagulant, water, and oil, the oil and water being provided in a volume ratio being from 0.7 to 1.3 times the oil-to-water volume ratio of the drilling fluid. The drilling fluid is mixed with the coagulant, the polymer solution, the oil, and the water in any order to provide an input fluid. The mixture is centrifuged to separate solid materials from the input fluid to provide a treated drilling fluid.