Desalination (Brackish and Sea Water) A Resource Management Strategy of the California Water Plan California Department of Water Resources July 29, 2016 Desalination (Brackish and Sea Water) Table of Contents Desalination (Brackish and Sea Water) .................................................................................................... 1 Introduction ............................................................................................................................................... 1 Salt and Salinity ........................................................................................................................................ 2 Definition of Desalination ..................................................................................................................... 2 Description of Salts and Their Origin ................................................................................................... 2 Salinity Measurements .......................................................................................................................... 3 Degrees of Salinity ................................................................................................................................ 3 Sources of Water for Desalination in California ....................................................................................... 5 Source Water Classifications ................................................................................................................ 6 Subsurface Water .................................................................................................................................. 7 Surface Water ........................................................................................................................................ 8 Desalination as a Water Treatment Technology ....................................................................................... 8 Introduction ........................................................................................................................................... 8 Overview of Types of Desalination Technologies ................................................................................ 9 Thermal Distillation Processes .......................................................................................................... 9 General Membrane Separation ........................................................................................................ 10 Electrodialysis and Electrodialysis Reversal .................................................................................. 10 Osmosis (Forward and Reverse) ..................................................................................................... 12 Basic Elements of a Desalination System ........................................................................................... 13 Raw Water ...................................................................................................................................... 14 Intake............................................................................................................................................... 14 Pretreatment .................................................................................................................................... 15 Blending .......................................................................................................................................... 16 Desalination .................................................................................................................................... 16 Post Treatment ................................................................................................................................ 17 Finished Water ................................................................................................................................ 17 Distribution ..................................................................................................................................... 17 Solids and Liquid Waste Disposal .................................................................................................. 18 Concentrate Management ............................................................................................................... 18 Desalination in California ....................................................................................................................... 18 History of Desalination in California .................................................................................................. 19 Brackish Groundwater .................................................................................................................... 19 Sea Water ........................................................................................................................................ 20 Current Desalinated Water Use in California ..................................................................................... 22 Current Brackish Groundwater Desalination .................................................................................. 22 Current Seawater Desalination ........................................................................................................ 24 Future Desalination in California ........................................................................................................ 24 Legal and Regulatory Framework of Desalination in California ............................................................ 25 Planning and Management of Water Resources ................................................................................. 25 Protecting Water Quality .................................................................................................................... 25 Protecting Drinking Water .................................................................................................................. 26 Environmental Laws for Protecting Resources ................................................................................... 27 Protecting Endangered Species and Habitats ...................................................................................... 27 Regulatory and Permitting Agencies .................................................................................................. 28 Regulations for Water Use Efficiency ................................................................................................ 28 Potential Benefits .................................................................................................................................... 28 Expanding Local Water Supplies ........................................................................................................ 28 July 29, 2016 i Desalination (Brackish and Sea Water) Improving Water Supply Reliability ................................................................................................... 31 Providing Emergency Supply ............................................................................................................. 32 Potential Costs ........................................................................................................................................ 32 Major Implementation Issues .................................................................................................................. 33 Permitting and Regulatory Framework ............................................................................................... 33 Energy Use and Sources ..................................................................................................................... 34 Climate Change ................................................................................................................................... 35 General ............................................................................................................................................ 35 Adaptation ....................................................................................................................................... 35 Mitigation ........................................................................................................................................ 36 Funding ............................................................................................................................................... 36 Intakes and Ocean and Freshwater Ecosystems .................................................................................. 38 Concentrate (Brine) Management ....................................................................................................... 38 Subsurface Extraction ......................................................................................................................... 40 Planning and Growth .......................................................................................................................... 40 Recommendations ................................................................................................................................... 41 Policy .................................................................................................................................................. 42 Actions ................................................................................................................................................ 42 Desalination