Research On The Biochemical Treatment Of Penicillin Wastewater

Antibiotics are chemical substances produced by certain microorganisms, which can inhibit and kill other microorganisms in low concentrations. Its discovery and application has played a huge role in human health and disease control. However, with its mass production and applications, it has resulted in serious environmental problems. For example, a large number of high concentrations organic wastewater will be produced in the producing process of antibiotics, which is characterized by high concentrations of organic compound, the existence of bio-toxic substances, high chroma, wide fluctuation of pH. So it is too difficult to treat as one of the toxic organic wastewater.The projects had screened and domesticated a high drug-resistant and high degradation strain named AF-1 and also made a systematic research on its physiological and biochemical characteristics, growth conditions, degradation performance, drug resistance mechanism and so on.The characteristic analysis of morphological and physiochemical showed that AF-1 belonged to genus Bacillus (Bacillus sp.).The optimum growth conditions of the strain were studied by spectrophotometric turbidimetry and the results showed that the optimum growth conditions of AF-1 were incubated about 24 hours in the ordinary culture medium with initial pH 8, temperature 30℃. The optimal carbon and nitrogen sources were respectively glucose, ammonium sulfate. AF-1 has a strong salt-tolerance and grows well as the NaCl concentration reaches 30 g/L. The result of drug-resistant test showed that 10 g/L of penicillin had little effect on the strain growth.In this paper the methods of UV-spectrophotometry and CODCr were adopted to detect the degradation rate of penicillin. The optimal degradation conditions were determined by changing the carbon and nitrogen sources and their usage, temperature, shaking speed, pH, incubation time and penicillin concentration conditions, which are glucose dosage 1.5 g/L, ammonium sulfate dosage 2 g/L, initial pH 7, temperature 30℃, shaker speed 120 r/min. When AF-1 was incubated for 48 h in the air bath in penicillin analog wastewater with concentration of 1000 mg/L at the optimal condition, it had the maximum penicillin degradation rate and CODCr removal rate, respectively 99.5%, 63.7%. Penicillin concentration less than 5 g/L has little effect on the degradation rate of penicillin, but a greater impact on the CODCr removal rate. With the increase of penicillin concentration, CODCr removal rate on a downward trend. Comparisons were made to the scanning spectrum of the wastewater before and after treatment, and then we could draw a conclusion that the penicillin molecule in the wastewater had indeed disappeared. Degradation kinetics experiment of the strain showed that AF-1 had a very high degredation efficiency to penicillin, and all the penicillin molecule would be degraded in 10 minutes. According to some relevant literature, we can see that in the growing process, AF-1 producesβ-lactamases, which can hydrolyze penicillin molecules and make them lose activity.