| The automotive coating wastewater has many kinds of pollutants and low biochemical degradation,the treatment methods of it are mostly physicochemical-biochemical methods.Aerobic granular sludge has the advantages of good sedimentation performance,high microbial content,adsorption and resistance to the impact of toxic substances,having the potential to be applied to the treatment of actual industrial wastewater and improve the pollutants removal efficiency.In the process of cultivating aerobic granule sludge in sequencing batch reactor,the traditional method of cultivating and acclimating was carried out in parallel with the method of simultaneous cultivation and acclimation,exploring the method for quickly cultivating and acclimating aerobic granular sludge based on automobile coating wastewater from the view of cultivation time and sludge properties.The aerobic granular sludge was used to treat the automotive coating wastewater that was treated by first-class physicochemical treatment and optimizing the operating parameters through orthogonal test methods to achieve the best removal efficiency,The feasibility and good treatment efficiency of applying aerobic granular sludge technology to the biochemical treatment stage of automotive coating wastewater treatment process is verified,and it provides theoretical basis for engineering applications.In view of the high COD value of the effluent,the adsorption characteristics of the aerobic granular sludge on the organic pollutants in automotive paint wastewater was studied by means of dynamic adsorption and static adsorption,to provide the theoretical basis for the effective separation of slow biodegradable organics and readily biodegradable organics in automotive coating wastewater to further reduce the COD value of effluent by utilizing the adsorption effect of aerobic granular sludge,and the new ideals for reducing the energy consumption of refractory organic wastewater.The research results are as follows:(1)From the view of granulation process,the traditional method of cultivating and acclimating completes granulation earlier;from the view of the duration of the cultivation of aerobic granular sludge with the ability to treat automotive coating wastewater,the method of simultaneous cultivation and acclimation needs less time;from the view of the physical properties of aerobic granular sludge,the aerobic granular sludge obtained by simultaneous cultivation and acclimation is superior to the sludge cultivated and acclimated in terms of particle size,mechanical strength,microbial biomass and sedimentation performance.In conclusion,adopting the method of gradually increasing the proportion of automotive coating wastewater in the simulated wastewater to simultaneously cultivate and acclimate can quickly obtain aerobic granular sludge that can be applied to the treatment of actual wastewater.(2)After the first-stage materialized automotive coating wastewater was treated with aerobic granular sludge that was previously cultivated,the effluent of NH4+-N and PO43--P was respectively stable at 10mg/L and 1mg/L,and the COD effluent can also achieve below 100 mg/L.According to the orthogonal test,when the aeration rate is 180 L/h,the influent organic load is 4 kg COD/(m3·d),and the p H is 7.5,having the best pollutants removal efficiency,the removal rate of COD,NH4+-N,PO43--P were 81.6%,85.1%,77.5% respectively.The variance data shows that aeration rate is the main effect on the aerobic granular sludge pollutants removal efficiency among the three operating parameters.(3)The results of dynamic adsorption tests showed that the aerobic granular sludge had a certain initial adsorption of organic pollutants in automotive paint wastewater.Within 30 minutes,COD was rapidly removed,and the removal rate reached 66.6%.After 180 minutes,the aerobic granular sludge basically became stable,the COD removal rate was 80.6%.The results of static adsorption test show that the adsorption amount is the maximum when the temperature is 35 °C and the p H is 7.0.The adsorption kinetics analysis shows that the pseudo-second-order kinetics model can better characterize the adsorption mechanism,indicating that the main limiting factor for the adsorption rate is the adsorption and binding rate of organic molecules at the adsorption site,which is dominated by the chemical mechanism.The innovation of this paper is to provide new ideas and methods for rapidly cultivating aerobic granular sludge that can treat automotive coating wastewater,and study on the adsorption characteristics of aerobic granular sludge to organic pollutants in actual wastewater. |
PDF Full Text Request