Method and system for extracting and recovering hydrocarbons from wastewater and treating the water to improve its condition. A series of specific unit operations result in the extraction of hydrocarbons, solids and contaminants and the treatment of water to a condition which is fit for re-use or environmentally sustainable discharge. Phase separation between the water and hydrocarbons is effected using flotation techniques followed by collection of the hydrocarbons using a movable collection surface. The aqueous phase is processed by multiple filtration steps. The result is significant extraction and recovery of hydrocarbons and conservation of water for re-use or discharge to the environment in a process which is continuous and scalable for large or small operations.