Experimental Study on the Treatment of Pharmaceutical Wastewater by Hybrid Biological Reactor

An experimental study on treatment of pharmaceutical wastewater with hybrid biological reactor was carried out. This went on three stages, which are the start-up, the running of the reactor and the influence of different conditions on it. The results indicate that the COD removal rate was gradually raised by more than 50%. When the influent COD was less than 500 mg/L, the effluent COD was less than 180mg/L and the optimum HRT was 6 h. When the influent COD was more than 500 mg/L, the removal rate of COD was 46%-72% and the optimum HRT was 8 h. When the aeration rate between 0.36m(3)/h-0.52m(3)/h and the DO was around 5mg/L, the COD removal rate reached 64%. Besides, operation efficiency has been improved by optimizing control parameters in continuous running of reaction system. Pharmaceutical wastewater is characterized as complex contents, high pollutant concentration, intense color, low biodegradability. It is commonly recognized as one of the most refractory industry wastewater [1, 2]. Till now, the commonly adopted treatment method of pharmaceutical wastewater is activated sludge process, which generally includes conventional activated sludge process, deep shaft aeration process, biological fluidized bed process and biological contact oxidation process. But these processes do many problems such as large quantity of residual sludge, too much foam and sludge bulking. Besides, it has high power consumption, high operation cost and low treatment efficiency. Therefore, hybrid biological reactor, a high-efficiency reactor with both the advantages of activated sludge process and bio-film process [3, 4], was used in this experiment. This field bench-scale experiment, with pharmaceutical wastewater from a pharmaceutical factory of Taiyuan as influent, was carried out to test a new treatment process for the pharmaceutical wastewater treatment and to determine reasonable and economic parameters of the process. The results are useful for the advancement and the operation of existing treatment system of this pharmaceutical factory.