"Desalination plants add salt-based chemicals like iron chloride or aluminum sulfate to remove dirt, and antiscalants to prevent salt buildup," he told DW. One way to soften the impact of discharged brine is to dilute it, as happens at the massive Carlsbad Desalination Plant in drought-prone California. Which is why knowledge of the local seascape is important when building a desalination plant. In Tenerife, Spain, an EU-funded project called Sea4Value is mining desalination brine for critical raw materials. Most desalination plants currently run on the fossil fuels that emit planet-heating greenhouse gases.