Research On The Performance Of ABR Treating High Concentration Petrochemical Wastewater

The treatment of petrochemical wastewater is always the focus of environmental protection research. With the typical characteristics of high COD concentration, high colority, poor biodegradability and consisting of toxic material, petrochemical wastewater is hardly met the discharged criteria through ordinary treatment process.The main focus of this thesis based on the treatment of petrol additive wastewater using the anaerobic baffled reactor (ABR). The pollutant removal efficiency of ABR was fully studied. Some influencing factors which could effect the performance of ABR were analysed, too. According to some experiments and design work, how to choose some key parameters was also discussed. And the unique phenomenon of"re-degenaration"was found when treating non-degradable wastewater by ABR. The result showed that the ABR is suitable and efficient to treat petrochemical wastewater and this result could provide a good sample to treatment of similar wastewater.The anaerobic baffled reactor (ABR) is a new anaerobic bio-reactor of high efficiency. In the ABR, the wastewater is well mixed with the active sludge. Meanwhile, because of the unique baffled structure and hydrodynamics, the granular sludge could be form in favorable condition.In this thesis, the treatment of wastewater discharged from a petroleum additive manufacturer was studied in small scale. A 36L volume anaerobic baffled reactor of 6 compartments was used in this study. Profiles of COD, pH, ALK, VFA and MLSS against time had been monitored and analyzed. The effect on the performance of ABR reactor by some controlling factors such as volumetric loading rate (VLR), HRT, hydrodynamic loading and upflow velocity (Vs) was discussed, too. The effect of shock loading on ABR performance was also studied. Finally, the commissioning testing of a newly built ABR treatment plant was discussed. The result shows that:In small scale, it cost three months to start the ABR reactor. The COD removal rate was always above 80% when VLR ascend from 0.83kgCOD/(m3.d) to 2.8kgCOD/(m3.d). The ABR reactor showed its best treatment performance when inflow COD=15000mg/L, VLR=2.5kgCOD/(m3.d), HRT=6d.In operational experiment, it was revealed that The ABR reactor showed its best treatment performance when VLR=2.5kgCOD/(m3.d). When VLR was fixed, the ABR reactor performed better when COD was higher and HRT was longer. When inflow concentration was fixed, more COD was removed when HRT was longer. In order to have satisfactory treatment efficiency, the Vs is suggested to choose a slow one. So, in the design of a real ABR treatment plant, the VLR=2kgCOD/(m3.d) , HRT=10d , inflow COD=20000mg/L , Vs=0.25m/h. Then the unique"re-degradation"pattern is discussed while treating non-degradable wastewater using ABR process. Refer to two shock loading patterns usually happens in factory, how the ABR reactor behave when facing shock loading is also studied.The operational datum of the ABR treatment plant demonstrates that the recently loaded active sludge needed time to adapt to the petrochemical wastewater. After 15 days monitor indexes began to show similar pattern in small scale. Some suggestions were given to improve the design and operation of ABR reactor.