As [25]. After pretreatment, the treated biomass was washed and collected in the biomass buffer tank. The biomass was washed two times using a belt presser and two washing tanks. Because of the enzyme activation, H2SO4 was used in the first washing tank to neutralize the pH. This washing process required more time than the pretreatment process. Therefore, the pretreatment process could not be continuously operated. In order to operate continuously, the development of a simple and efficient washing process is needed.