Biological Nitrogen Removal of High Salinity Produced Water in Sequencing Batch Reactors

Produced water contains a complex mixture of organic and inorganic materials such as oil, heavy metals and salts. The water produced in PETROBRAS offshore platforms is transferred through pipelines to onshore terminals where it has to be treated before it is discharged through outfalls. Today, the only one plant in operation in land treats produced water through a physical chemical process. Historical data showed that oil and grease, ammonium nitrogen, barium and boron concentrations were often higher than the discharge limits established by the Brazilian legislation. To solve this problem, the Wastewater Treatment R&D group of PETROBRAS started a research project to evaluate different treatment processes in parallel with the existing plant at the São Sebastião Terminal, São Paulo, Brazil. The group assessed processes for primary, secondary and tertiary treatment in order to reach the quality required to comply with the Brazilian environmental legislation.