Pilot-scale test of hydrolyzation-acidification-oxidation process for the wastewater from dyestuff production

In order to investigate the feasibility of hydrolyzation-acidification-oxidation process for wastewater discharged from dyestuff production and to provide the optimal design parameter for the practical project, a pilot-scale test was carried out. The experimental results showed that when the influent was less than 1200 mg/L, the hydraulic retention time of hydrolyzation reactor, acidification reactor and oxidation reactor were 6.0 h, 7.0 h and 6.0 h respectively, the effluent could meet the requirement of National Second-level Standard. Although low COD removal degree could be obtained in the process of acidification, it improved the BOD/COD ratio of wastewater significantly, which accelerated the biodegradation of hard-utilization organic and fasten the next step of oxidation. In addition, it is indicated that two steps of adding-amidogen and doffing-amidogen is involving in the hydrolyzation-phase and acidification-phase respectively for the degradation of macro-molecular heterocyclic organic in the wastewater. Furthermore, the microbial succession in the oxidation reactor can indicate the operation of the system and the change of water quality.