Systems and methods for disposing of produced water as steam released into the atmosphere. After wastewater is prepared for disposal by suitable filtering and/or treatment, it flows into a preheating tank where it is heated prior to disposal by liquid filled preheating coils extending from the heating tank which are heated by burner boxes. From the preheating tank, the preheated water flows into evaporation coils, where it is heated above boiling and released as steam. Water flowing into the tank passes adjacent the evaporation and preheating coils near the burner boxes. The preheating coils may contain antifreeze which can be circulated to prevent freezing of the preheat tank when not in use or to maintain the temperature of the preheat tank. The system may be moved with the preheat tank filled with preheated water to facilitate the use another location.