associated apparatus such as the blow out preventers and surface mud lines etc several disposal lines 29 32 with auxillary control valves are included in the well system 11 so that fluid from either the surface equipment 12 or the brine treatment unit 14 can be discharged to a suitable disposal in a pollution free and environmental safe region an inlet 32 to the pump 26 can be used to introduce relatively solids free brine into the brine treatment unit 14 prior to introduction of the brine into the well system 11 it must be cleaned of drilling mud both as to solids and oil materials for this purpose the drilling mud is displaced from the well system by circulating therethrough a suitable volume of clean water introduced into the mud pit 19 from inlet 24 the clean water is circulated by the mud pumps 16 a major portion of the drilling mud is removed from the well system and carried in the clean water which water can be discharged through one or more of the discharge lines to a suitable disposal region at this time a treated water is prepared preferably in the mud pit 18 by adding together.