Oxidation can destroy the dye completely, e.g. through the use of sodium hypochlorite (NaClO, common bleach) or hydrogen peroxide. Reduction of methyl violet occurs in microorganisms but can be attained chemically using sodium dithionite. Biodegradation has been well investigated because of its relevance to sewage plants with specialized microorganisms. Two microorganisms that have been studied in depth are the "white rot fungus" and the bacterium "Nocardia Corallina". Light alone does not rapidly degrade methyl violet, but the process is accelerated upon the addition of large band-gap semiconductors, TiO2 or ZnO. Many other methods have been developed to treat the contamination of dyes in a solution, including electrochemical degradation, ion exchange, laser degradation, and absorption onto various solids such as activated charcoal.