Several methods exist for purifying RNA such as trizol extraction and column purification. Reverse osmosis process for water purification does not require thermal energy. These are semipermeable membranes manufactured principally for use in water purification or desalination systems. Multiple methods of nucleic acid purification exist. It distributed water, tents, hygiene kits, water purification tablets and buckets. It is also used for water purification. The processes below are the ones commonly used in water purification plants. Rainbow trout is sometimes used as an indicator for water quality in water purification facilities. It is one of the methods used in the purification of water. It is also used in water purification. UVGI is used in a variety of applications, such as food, air, and water purification. MS with extraction, purification, and derivatization of the samples. Catalytic purification and hydrocracking are together known as hydroprocessing. Sake is often consumed as part of Shinto purification rituals. This work became the basis for present day systems of municipal water "purification".