Treated produced water in irrigation: Effects on soil fauna and aquatic organisms.

Produced water (PW) is a mixture of formation water and injected water from oil and gas reservoirs, which contain a complex composition of dissolved and particulate organic and inorganic chemicals. High quantities of PW are extracted with the oil, which can be discharged into the environment, re-injected into the wells or treated for reuse. The present study aimed to evaluate the soil ecotoxicity under an irrigation system using treated PW (water-oil separation, sand filter, activated charcoal filter, reverse osmosis) for sunflower production, predicting conditions for PW reuse in the semi-arid region of Brazil.