The Catalytic Ozonation Refractory Pharmacy Wastewater

Since the pharmaceutical wastewater has kinds of compounds, low biodegradability, the important pollutants such as COD are out of criterion, the treatment of pharmaceutical wastewater is considered the one of the most difficult treatments for the most of pharmaceutical companies. So, in order to improve its biodegradability, we should pretreat the water. In these experiments, we treated the special pharmaceutical wastewater with the ozonation process coupled with SBR, then studied the effect of catalyst to increase treatment efficiency, researched the principle of the degradation and compared the redesigned reactor to old one. At last, we achieved several conclusions following.1, Ozone is preferable to pharmaceutical wastewater's pretreatment and can improve its biodegradability. We pretreated 600ml this water with 71mg/L ozone, sampling every 20min, then determined its factors such as pH, COD, BOD and chroma, The results show that ozone has very good removal effect to chroma, it can wipe off almost all the chroma in 10min, dropped from 320 to 0. COD was removed responding to stair reaction law, in another word, more time, better removal effect, and it dropped from 4220mg/L to 2087mg/L after 3 hours' treatment, the degradation rate reached to 50.5%. pH changed greatly from 12.8 to 5.8,it showed that there was acidity substance come into being. B/C increased a little notably from 0.18 to 0.35, it made out that ozone can improve its biodegradability.2, The catalysis of transition metal oxide is very powerful, and can greatly shorten the pretreated time of ozonation. We introduced the oxide of Mn, Cu, Fe, Co and Pd as catalyzer, and used active carbon fibre as carrier, then pretreated the refractory pharmaceutical wastewater by Heterogeneous Catalytic Oxidation. The results are that transition metal oxide can greatly advance the efficiency of ozonation. If we pretreated 600ml this water with 71mg/L ozone, it ,very soon in 40~60min, can reach favorable effect. For instance, if we use Fe oxide as catalyzer, chroma will be entirely eliminated in 7min, and COD removal rate can attain 62.1%, more than therate of using single way of ozone treating 3h, and on the temporary, the B/C is 0.36. At those kinds of catalyzer, using Fe, Co and Pd oxide in pretreatment will have comparatively good catalyze effect, COD removal rate can attain partly 57.3%, 62.1% ' and 62.9%, B/C increased partly to 0.33, 0.35 and 0.35, and Fe was especially best among the three. So this experiment selected Fe oxide as ozonation catalyzer, not only for its good effect, but also for its low cost and easily obtaining. Furthermore, we studied the influenced factors of pretreatment such as original pH, ozone dosage, catalyzer casting quantity, reaction hour and original contamination concentration, and found that all factor were correlated to a given concentration of wastewater, expect alkalescence condition can accelerate pretreatment effect prevalently, so there must exist a best-of-all reaction condition, and the condition to a given COD concentration of wastewater is that original COD is 4220 mg/L, Fe oxide is 3.6mg/L, ozone airflow is 40L/h, original pH is 12.5, and reaction hour is 40min. On this condition, COD of outflow water fell to 1565mg/L, and its removal rate can reach 62.9%, on the temporary, B/C unproved to 035, pH dropped to 9.4, and chroma eliminated in 7min.3, If the refractory pharmaceutical wastewater was treated by the catalytic ozonation process coupled with SBR, it can let flow reaching the mark.. We accommodated pH of the outflow into 7~7.5, then put it in a SBR reactor for deeper treatment which diameter is 200mm and available dimension is 4L, using vermiculation pump, beater and time-controlling switch for automation. An react cycle was 12h composing of 15min's inflow, 2h's mix, 8h's charge, 1.5h's deposition and 15min's drainage. HRT was 48h and the temperature was 15~20C. After the system running stable, we measured COD and BOD of outflow. The average COD of ten cycles' was 250mg/L, correspondence with 84.1% removal rate,...