Experimental Study On Treatment Of Secondary Effluent From Sewage Plant Of Pharmaceutical Park With Ozone And AC Combined With SBBR Process

Pharmaceutical wastewater has the characteristics of large fluctuations in water quality,water volume,high content of refractory pollutants,and strong microbial inhibition.The comprehensive sewage treatment plant in the Pharmaceutical park,as the terminal treatment place for Pharmaceutical wastewater,must have good decontamination efficiency in order to adapt to the increasingly strict discharge standards.This project is based on the upgrading project of a comprehensive sewage treatment plant in a Pharmaceutical park in Hebei Province.Through on-site investigation and problem diagnosis of the existing treatment process of the sewage treatment plant,we decided to strengthen the treatment efficiency of the existing biochemical unit by adding suspended carrier filler,and the ozone-AC process was used as the advanced treatment process.This thesis takes the secondary biochemical effluent of the sewage plant as the research object,and aims to meet the discharge standards after treatment.A series of experimental studies are carried out through the combined process of ozone and AC combined with SBBR,in order to providing a certain guidance for the subsequent reconstruction design of the sewage plant.The SBBR reactor has a dosage of"polyurethane+high-density polyethylene"combined filler at 30%.After 35 days of film hanging and microbial domestication,the reactor's treatment effect on the secondary effluent tends to be stable,and the effluent COD,TN and chromaticity are stable at 88mg/L,26mg/L,and105 times,respectively,and the removal rates are 33%,21.21%,and 19.2%,respectively.Due to the low ammonia nitrogen concentration in the experimental water,the ammonia nitrogen concentration in the effluent after treatment by the SBBR reactor It can stably reach the first-grade A standard?<5mg/L?,and the ammonia nitrogen removal rate is about 80%.In order to further improve the treatment effect of the SBBR unit,experiments were performed to optimize the operating conditions such as the amount of carbon source addition,the mode of carbon source addition,and the amount of aeration in the aerobic section of the reactor.The experimental results show that:The addition of source significantly improved the denitrification effect of the system.When the external carbon source of COD/TN=1.5,the TN of the effluent can be reduced to about 11.6 mg/L,which meets the effluent requirements of Class A.At the same time,the external carbon source is beneficial to Pharmaceuticals.Difficult biochemical degradation of organic matter in the wastewater produced a certain co-metabolism,resulting in a slight decrease in the COD concentration of the effluent as the external carbon source increased;the different ways of adding external carbon sources had little effect on the removal of COD,But for the denitrification effect,the one-time dosing mode of the carbon source is better than the dosing mode in two batches;the optimization results of the dissolved oxygen amount in the aerobic section of the SBBR reactor show that in order to ensure the adequate SBBR reactor for organic matter degradation,the dissolved oxygen concentration in the aerobic section should preferably be higher than 3.5mg/L.By adding PAC to the SBBR reactor to enhance the treatment of color and COD,the experimental results show that with the increase of the activated carbon dosage,the effluent COD continues to decrease.At 50mg/LPAC dosage,the effluent COD It can be reduced to72mg/L,and the chromaticity of the effluent can be stabilized at 85 times;through analysis of the effect of adding PAC in the SBBR unit,it can be seen that the increase in the COD removal rate of the reactor after the addition of PAC is only caused by the adsorption effect of activated carbon itself That is,the addition of PAC did not improve the overall removal effect of microorganisms in the reactor.The experimental study of the ozone oxidation unit shows that the COD of the effluent decreases continuously with the increase of the contact time of O₃.Under the working condition of the ozone generator in this experiment,if the ozone oxidation alone is used to make the COD of the effluent reach the standard,the contact time is 140min.When the time is 60min,the effluent color can reach the standard.The COD concentration of the effluent is58.5mg/L,the COD removal rate is 17.8%,and the average removal rate of UV₂₅₄54 is 39%.In addition,the ozone oxidation effect is poor under low pH and low temperature conditions.Therefore,in the actual operation of the sewage plant,the insulation measures of the ozone oxidation unit under low water temperature in winter should be considered to maintain the ozone treatment effect.The GAC and BAC units were used to treat the ozone oxidized effluent to further reduce the effluent COD.The COD adsorption effect of the GAC unit is closely related to the duration of contact.The longer the contact time,the better the treatment effect.In the initial stage of adsorption,the COD of the GAC effluent can be reduced to a very low level,which can be used for the production of high-quality recycled water,and the failure Activated carbon can be oxidized and regenerated by ozone;BAC unit experiment results show that when HRT is controlled at 25.4min,the COD of the effluent is about 48.5mg/L,and the average removal rate reaches 16.4%,which can make the COD of the effluent steadily meet the emission requirements of Class A.