Brine Disposal Considerations Contamination from chemicals used for pretreatment, membrane cleaning and preservation Contamination for concentrated source water constituents (arsenic & radionuclides) Changes in salinity regime caused by brine itself Contamination or impairment of fish resources and habitats Slide Design stolen from Dr. George Ward
Environmental Considerations for Brackish Groundwater Desalination Ecological effects of brine disposal Increased energy needs Aquifer depletion or contamination
Environmental Considerations for Brackish Groundwater Desalination Ecological effects of brine disposal Increased energy and water needs Aquifer contamination
Additional energy to produce brackish desalinated water? ~6.8 Kwh to produce 1,000 gal desalinated water 170 gpd is per capita use or 62,000 gal/year 421 kWh to produce enough desalinated water for year … this is 3% of the amount used on individual annual basis iStockphoto/Larry Lawhead Data Source: Stillwell, King, Webber
Additional carbon to produce brackish desalinated water? ~6.8 Kwh to produce 1,000 gallons desalinated water 6,800 Kwh to produce 1 Mgd or 137 Mwh for 20Mgd CO2 emissions: Coal = 142kg/d Gas = 71 kg/d … this is 5 times the amount of emissions from a conventional surface water source iStockphoto/Larry Lawhead Data Source: Stillwell, King, Webber
Additional water needs for 20 Mgd Brackish Desal facility? 6.8 mW for 1 million gal brackish water 15 – 40k gallons for 1 mW assume 66% recovery… … 3 – 8 Mgd additional water needs for power to process 30 Mgd iStockphoto/Larry Lawhead
Additional water needs for 20 Mgd Desal facility? Australian desalination plants producing 36-120 Mgd use wind, solar, wave A Drought-Proof Source of Water? 3 – 8 Mgd?
Positive impacts of Brackish Groundwater Desalination? Reduce development pressure on other sources May allow other sources to be used for environment Costs make water conservation more attractive Works well with water conservation programs Works well with renewable energy
The Sierra Club’s Perspective… Photo: Jennifer Ellis, National Wildlife Federation Tyson Broad Lone Star Chapter Sierra Club With proper planning, siting, attention to all energy and environmental factors…Desal plants could be a significant part of a comprehensive water supply program that includes advanced water conservation and drought management measures.