The process for decolorization of wastewater was divided into three processes. First is the Physical process such as, adsorption with activated carbon which is high porosity and ability to absorb color. But, the problem of this process is a blockage at the surface layer of charcoal and high cost of recycling. Second is a chemical process such as coagulation and flocculation by using alum, lime and iron compounds. This method is highly effective, but it will be much sludge cause to find a way to dispose of the sludge. The last is the biological process which was applied to remove the color of wastewater, such as using algae, bacteria and fungus. Algae are effective to reduce colors and not add chemicals to the environment, but there are limits on the temperature, pH, nutrients, and inhibitors. The using of bacteria is the effective process but it cannot withstand the high concentrations of toxic while the fungus has a few limitations and has durable than bacteria. So, it is appropriate to reduce color. From this capability, the fungus has been applied in the treatment of waste water from the production of ethanol.