Integrated Produced Water Management in a Desert Oilfield Using Wetland Technology and Innovative Reuse Practices

The water that is produced during the exploration and production of oil and gas represents one of the largest industrial waste streams worldwide [1]. This water occurs not only during the crude oil recovery, but also during other forms of fossil energy recovery including shale gas, oil sands and coal bed methane [2]. Produced water may include water from the reservoir, natural formation water and water injected into the formation, along with any chemical substances used during the production and treatment processes. Even after the majority of the oil and gas has been extracted, produced water is typically contaminated with residual hydrocarbons. Stricter environmental policies drive the vision of environmentally friendly treatment of produced water. The North American region is the largest market for produced water treatment; more than 20 billion bbl (barrels of oil) of produced water are annually produced in the USA alone [3]. The worldwide production of produced water associated with hydrocarbon recovery exceeds 77 billion bbl per annum [4]. The Middle East market remains a key growth area due to increasing awareness and fresh water shortage. In the oil and gas industry, produced water management represents a major challenge, since if it is not properly managed it can have an adverse impact to the environment [5, 6]. Produced water quality varies among different oil fields and wells, depending on the produced hydrocarbon type and the geological formations [2]; however, specific compounds are usually present in this water, such as oil and grease, salts (i.e., total dissolved solids, salinity) and other organic and inorganic compounds (e.g., emulsion breakers, chemical additives, solvents, heavy metals etc.). The levels of these constituents in produced water usually define the required management options to be selected. Due to the high salt content and petroleum hydrocarbons, produced water cannot be released to the environment, since it can affect the soil salinity and plant productivity [7]. As the levels of salinity increase, so does the treatment cost. Therefore, desalination of produced water is a widely applied method to improve its quality and make it appropriate for reuse options [8]. Large volumes of produced water are generated as an associated co-product of oil production in many countries; the management of which often imposes a limitation on oil production. In many cases, a portion of this water is re-injected into reservoirs to maintain pressure for the oil wells. The