Study On The Effect Of Twostage Intermittent Aeration High-efficiency Reactor On The Decarbonization And Denitrification Of Juice Wastewater

In recent years,as the living standards of urban residents continue to improve,the demand for juice beverages gradually increased,the rapid development of juice production enterprises,juice wastewater emissions continue to increase.Juice wastewater has the characteristics of high sugar,high acidity and large changes in water quality and quantity,if not treated properly,it will seriously threaten the local water environment and even cause great harm to people’s safety and health.Therefore,it is especially urgent to develop a new reactor with low economic consumption,to achieve the requirements of easy operation,energy saving and high efficiency,and to realize the optimization of effluent quality,which is of practical significance to protect and improve the water body environment.A mechanical time-controlled intermittent aeration reactor(patent number:ZL201710651869.6)was used in this experiment.The effect of carbon and nitrogen removal in the reactor was discussed by adjusting the parameters of influent frequency,C/N ratio,aeration time and precipitation time.Firstly,the carbon and nitrogen removal effect of the reactor in the volume load lifting stage was investigated.Then,the operating conditions of the experiment were changed to explore the carbon and nitrogen ratio of different single variables,operation cycles,the exposure stop period and the exposure stop time ratio,and the carbon and nitrogen removal effect of the reactor were compared to determine the optimal operating conditions of the reactor.Finally,combined with the characteristics of sludge in the test process,the change of sludge parameters was analyzed to verify the sedimentation performance of sludge in the reactor.The experiment lasted 145 days.The main contents and conclusions are as follows:(1)the test start stage,through the domestication of inoculated sludge,the pollutant effluent concentration has reached the standard and can be maintained in a stable state after 28 days of test operation.The measured data show that the total removal rate of COD and ammonia nitrogen was stable above 97%,and the total removal rate of total nitrogen was stable at about 92%,which indicates that the device operates stably and has good impact resistance.(2)In the volumetric load lifting stage,the volumetric load increases from1.2kg COD/(m~3·d)to 2.0kg COD/(m~3·d).After the stable operation of the reaction device,the pollutant removal effect was good,and the effluent water quality reached the standard.The mean concentrations of COD,ammonia nitrogen and total nitrogen in the final effluent were 35.1mg/L,4.1mg/L and 9.1mg/L,respectively.The mean removal rates were 97.28%,97.36%and 90.64%,respectively.It proves that the device can adapt to water quality changes quickly and the reactor has good pollutant removal ability.(3)At the stage of operation parameter adjustment,single factor variable was controlled,and the effect of carbon and nitrogen removal of the reactor was compared.The optimal operation condition was determined as influent COD/TN was 10,the operating cycle of 8h,the inlet water time of 20min,aeration of the primary reactor20min,40min stop,aeration of the secondary reactor 30min,30min stop,cyclic aeration7h,sedimentation time 40min,waiting for the next cycle of water intake.Under this condition,the mean concentrations of COD,ammonia nitrogen and total nitrogen in the final effluent were 39.45mg/L,3.4mg/L and 6.15mg/L,respectively,and the mean removal rates were 97.54%,97.13%and 95.7%,respectively.The experimental operation was efficient and stable,and the removal of pollutants in the reactor was good.(4)Sludge performance analysis stage,through the observation of the sludge characteristics,analysis of the reactor sludge settling performance,found that part of the working condition of sludge performance was poor,the main reasons include p H,organic matter concentration and the dissolved oxygen content was low,the solution is to add certain alkalinity and increase the organic concentration to ensure suitable reaction conditions and complete the sludge performance recovery as soon as possible.The experimental device has stable carbon and nitrogen removal effects under different COD volume loads,and has the characteristics of economic,efficient and strong oxygen filling capacity.The experimental study provides a new way for the treatment of juice wastewater,and provides reference value for the practical application of juice wastewater treatment.