The conventional treatment methods for printing and dyeing wastewater are generally divided into two categories: biochemical + physicochemical and physicochemical + biochemical treatment processes. However, due to the lack of hydrolysis and acidification units, the actual operation of the aerobic biochemical unit is not complete enough, resulting in the problem of high cost of subsequent physical and chemical treatment . Adding the "hydrolysis + aerobic" series process of hydrolysis and acidification in front of the traditional aerobic biological treatment device can hydrolyze the organic substances that are difficult to degrade in the printing and dyeing wastewater, and generate a more biodegradable substance to improve the biodegradability of the wastewater. Degradability, thereby improving the COD removal rate of the traditional process. At present, many new domestic printing and dyeing wastewater treatment devices (including domestic sewage and printing and dyeing wastewater centralized treatment) all adopt the "hydrolysis-aerobic" biological treatment process developed by this process, and have achieved obvious environmental and economic benefits.