UASB-Biological Contact Oxidationcoagulation-Fenton-A/O Process For Treatment Of Pharmaceutical Intermediate Wastewater

With the rapid development of social economy and chemical science and technology,the pharmaceutical industry has also developed rapidly.The number of pharmaceutical companies in China is large,the scale is small,and the layout is scattered.There has always been a problem of high energy consumption and high pollution.The pharmaceutical intermediate wastewater has the characteristics of complex composition,high COD_Crr concentration,high nitrogen and high phosphorus,high salinity,deep chroma and poor biodegradability.It is difficult to treat and has serious environmental pollution.The pharmaceutical intermediate wastewater produced in the production process of a bio-pharmaceutical technology company was studied.The UASB-biological contact oxidation-coagulation-Fenton-A/O process was used to treat the pharmaceutical intermediate wastewater.And drew the conclusion as follows:?1?Under medium temperature conditions?35±2°C?,the reactor was inoculated with mature anaerobic flocculent sludge,and the artificially prepared glucose nutrient solution could activate anaerobic sludge in a short period of time,and gradually increased it.The influent concentration was used to acclimate the anaerobic sludge in the UASB reactor.After the reactor was successfully started,the pharmaceutical intermediate wastewater was used as the water in the UASB reactor to adjust the pH to 7.0?8.0.During the process of gradually extending the hydraulic retention time,the COD_Crr removal rate was gradually increased.When it reached 4d,The removal rate of COD_Crr reached 20.7%,but the concentration of NH₃-N and TP increased with respect to the influent concentration.Considering comprehensively,the optimal hydraulic retention time for the treatment of pharmaceutical intermediate wastewater by UASB anaerobic reactor was 4 days.?2?Using the inoculation membrane method to start the biological contact oxidation reactor,and using the combined filler,firstly cultivating the aerobic activated sludge with the prepared nutrient solution,the aerobic sludge was then domesticated by gradually increasing the influent concentration with the diluted UASB effluent until the influent was the UASB anaerobic effluent.The dissolved oxygen concentration was kept between2?4mg/L,under continuous aeration,and the water quality was monitored at intervals of 4h.When the aeration time was 48h,the COD_Crr removal rate reached 78.19%,and the treatment effect was the best.Taken together,the optimal aeration time for determining biological contact oxidation was 48h.?3?It was concluded that the effect of ferric chloride coagulant on the treatment of pharmaceutical intermediate wastewater was better than that of polyaluminium chloride.The experimental results showed that the best experimental conditions for coagulation treatment were:The dosage of ferric chloride was 2.2g/L,the pH was 8?9,the precipitation time was 30min,and the dosage of 1‰PAM was 3mL/L.Under the optimal experimental conditions,the removal rates of COD_Crr and TP were 27.0%and 91.8%,the effluent COD_Crr was about 2100?3800mg/L,and the effluent TP was about 0.1?0.3mg/L.?4?In the Fenton oxidation experiment,by single factor experiment and orthogonal experiment,the optimal reaction conditions were determined:n(Fe²⁺):n?H₂O₂?=1.5:1,30%H₂O₂ dosage was 15mL/L,influent pH was 4.5 and the reaction time was 4h.Other conditions were:the reaction temperature was room temperature,and the stirring speed was120r/min.Five repeated experiments showed that Fenton oxidation had a good treatment effect on high concentration pharmaceutical intermediate wastewater,COD_Crr removal rate could reach about 40%,and effluent COD_Crr was about 1200?2300mg/L.?5?Under the condition of room temperature,the dissolved oxygen concentration in the anoxic section of the reactor was controlled to be less than 0.5mg/L,the dissolved oxygen concentration in the aerobic section was 2 to 4mg/L,and the sludge concentration was 3 to 4g/L.The reflux ratio was kept at 50%.The effect of nitrate reflux ratio,C/N ratio and hydraulic retention time on the treatment effect of A/O reactor was studied.The experimental results showed that the optimal operating conditions for A/O process were:the reflux ratio of nitrifying solution was 2,the influent C/N ratio was 8,the hydraulic retention time of the anoxic section was 12h,and the hydraulic retention time of the aerobic section was 24h.At this time,the removal rate of COD_Crr and NH₃-N was the highest.Three repeated experiments were carried out under the optimal experimental conditions.The experimental results showed that the effluent water quality indicators could meet the requirements of the secondary discharge standard of the Integrated Wastewater Discharge Standard?GB8978-1996?.?6?The UASB-biological contact oxidation-coagulation-Fenton-A/O combination process was applied to a bio-pharmaceutical enterprise.The actual actual engineering operation results showed that it was feasible to use the combined process to treat the pharmaceutical intermediate wastewater.The removal rate of COD_Crr and NH₃-N in the biological contact oxidation reactor reached 78%and 50%,the removal rate of TP by coagulation reached 91%,and the removal rate of COD_Crr and NH₃-N reached 44%and46%.The removal rates of COD_Cr,NH₃-N and TP by A/O process reached 86%,86%and71%.All the indicators of operation and effluent could reach the secondary discharge standard of Integrated Wastewater Discharge Standard?GB8978-1996?,and the pharmacy fee was 28.29 yuan perton.