Seawater desalination facilities require an intake system capable of providing a reliable quantity of seawater at the best quality available

Seawater desalination facilities require an intake system capable of providing a reliable quantity of clean seawater with a minimum ecological impact. To meet these objectives, it is essential that a thorough assessment of site conditions be conducted. Physical characteristics, meteorological and oceanographic data, marine biology, and the potential effects of fouling, pollution, and navigation must be evaluated, and an appropriate intake design employed. As the first step in the pretreatment process, the intake will affect a range of feedwater quality parameters and determine the performance of downstream process systems. Intake designs are highly site specific, possibly more so then any other aspect of the desalination facility. The design, modeling, monitoring, and permitting activities that surround them, may represent as much as 20% of the capital cost of the entire facility, and it is possible that intakerelated issues may ultimately determine the feasibility and performance of the desalination plant itself. Environmental impacts associated with concentrate discharge have historically been considered the greatest single ecological impediment when siting a seawater desalination facility. However, recent analyses have noted that marine life impingement and entrainment associated with intake designs were greater, harder-to-quantify concerns and may represent the most significant direct adverse environmental impact of seawater desalination. This paper will consider the seawater intake technology options available for desalination plants, including intakes shared with electric power plants, and will review the technologies employed to minimize impingement and entrainment of marine life while meeting the intake’s objective of providing a reliable quantity of seawater at the best quality available.