There are three main types of volcano-composite or strato, shield and dome. Composite Volcanoes. Composite volcanoes, sometimes known as strato volcanoes, are steep sided cones formed from layers of ash and [lava] flows.The eruptions from these volcanoes may be a pyroclastic flow rather than a flow of lava.A pyroclastic flow is a superheated mixture of hot steam, ash, rock and dust.omposite volcanoes, sometimes known as strato volcanoes, are steep sided cones formed from layers of ash and [lava] flows. The eruptions from these volcanoes may be a pyroclastic flow rather than a flow of lava. A pyroclastic flow is a superheated mixture of hot steam, ash, rock and dust.
Desalination plants typically use reverse osmosis, a process that pushes saltwater through a membrane to create purified, drinking water. But in addition to being costly, and energy-intensive, reverse osmosis can negatively impact the environment.
Today there are more than 15,000 desalination plants in 120 countries. The desalination market is forecast to grow more than $70 billion in the next 20 years. About half of the world's desalted water is produced with heat to distill fresh water from seawater.