Advanced oxidation of polyvinyl alcohol wastewater by O3/UV

Polyvinyl alcohol (PVA) was commonly used in textile industry which could not be easily degraded by microorganism under the general conditions. As PVA was not readily biodegradable, its interference with conventional biological treatment methods meant the necessity of abiotic oxidative pretreatments before biological treatment. The relatively simple and flexible approach was O3/UV pretreatment. This study indicated that the treatment effect was obviously affected by the time, pH value, initial concentration of PVA and flow of O3. Under the conditions of O3/UV, with the indicator of Chemical Oxygen Demand (COD), the best conditions to degrade PVA were found. In this experiment, optimum reaction conditions for PVA pretreatment were obtained as following: 80 minutes for the reaction time, 0.5% for the concentration of PVA, pH=5 and 40L/h for the flow of O3. The removal ratio of COD was 95% when combined O3/UV with biodegradation treatment.