Review of water treatment methods with a focus on energy consumption

Water and energy are substantial mediums which allow to gain comfort and civilization development. Recently, humanity is facing a water scarcity problem as well as an energy crisis. Those factors forced to looking for alternative water sources and low energy solutions. In this paper water treatment technologies methods were described. Energy demand and cost of particular methods were analyzed. It was shown that conventional methods like coagulation and sedimentation are characterized by quite low energy demand. Whereas more advanced membrane techniques consumed much more energy. On the other hand they were able to obtain high removal efficiencies. It was noted that the most energy-intensive stage during water treatment was pumping. Whereas energy for performing purification stated only about a few percent of total energy demand. One of the newest approaches in water treatment is using renewable energy sources like wind, solar radiation or geothermal energy. It allows to decrease water treatment costs as well as reduces greenhouse gasses emission (expressed as carbon footprint). During designing water treatment plants water increase in water and energy demand supposed to be considered.