A method and apparatus for processing waste water generated during oilfield drilling operations with a mobile processing unit utilizing heat energy sourced from burning hydrocarbon fuel directly and/or capturing and using the exhaust heat energy generated by burning hydrocarbons in engines such as diesel engines in order to vaporize a dominant mass of the aqueous phase of the waste water while clarifying the heat source combustion gasses. The water vapor generated by the vaporization process may be discharged directly to the atmosphere or alternately condensed and captured for use as potable water. The residual waste water is thereby concentrated and the cost to dispose of the waste water is greatly reduced.