Research On The Efficiency Of FMBR In Treating Dairy Wastewater And The Characteristics Of Membrane Fouling In The Process

With the increasing demand for dairy products,the amount of wastewater generated by the dairy industry is also on the rise,posing a challenge for its treatment due to high concentrations of organic matter and salinity.The existing methods for wastewater treatment have limitations in terms of efficiency and cost,leaving room for further improvement.In this study,the actual dairy wastewater from a certain cow farm in Jiangsu Province was taken as the object of treatment,and a pilot-scale treatment study was conducted using a process primarily consisting of an aerobic membrane bioreactor（FMBR）.By controlling various system parameters and successfully domesticating facultative anaerobic bacteria,the experimental parameters were optimized through comparative experiments,and the treatment effect during operation was investigated,as well as the pollutant removal mechanism.The results showed that the FMBR system process can efficiently treat dairy wastewater.By domesticating activated sludge and controlling experimental parameters to initiate the FMBR system,comparative optimization experiments showed that the appropriate hydraulic retention time（HRT）was 24 h,and the optimal mixed liquor suspended solids concentration（MLSS）was approximately 11000 mg/L.FMBR with these parameters exhibited high removal rates for various indicators and showed strong resistance to shock loads.The biological diversity of sludge in FMBR was significantly richer than that in other conventional MBR systems.The effluent monitoring showed that the system kept COD effluent stable at 24.02±2.49 mg/L,with a removal rate of 97.59±0.69%,which was achieved by the synergistic metabolic action of aerobic and anaerobic microorganisms and membrane interception.The TN and NH₃-N removal rates were84.35±2.65%and 95.08±1.34%,respectively.The corresponding effluent concentrations were10.58±1.41 mg/L and 0.98±0.21 mg/L,and the main removal mechanisms were synchronized nitrification-denitrification and short-range nitrification-denitrification.The TP removal rate was98.54±0.34%,and the effluent was as low as 0.26±0.04 mg/L,which was achieved by traditional biological phosphate removal,gasification phosphate removal,and chemical-assisted phosphate removal.The study also addressed the issue of membrane fouling by studying the characteristics of fouling and exploring operational control strategies,such as backwashing,online chemical washing,and pump stopping ratios,to mitigate fouling of the FMBR membrane.Initial research on the modification of sludge to reduce EPS production and mitigate membrane fouling was also conducted.Results showed that online backwashing was insufficient to control membrane fouling when MFI reached 89.18%,and offline cleaning was required.The cycle of membrane fouling occurred approximately every 16 days and shortened with ongoing operations.Both PACl and PAC additions at 300 mg/L demonstrated significant reduction of EPS and potential to further mitigate membrane fouling.The optimal interval time for backwashing,online chemical washing,and pump stopping ratio were 2 hours,2 weeks,and 9:2,respectively.The FMBR process can adapt to the treatment of dairy wastewater,and it can provide engineering references for the treatment of wastewater from dairy farming,considering treatment efficiency and cost.In the future,based on this research,the following studies can be conducted:exploring the maximization of resource recovery and recovering proteins,lipids,and other substances from dairy wastewater that can be used to produce high-value products;using more advanced statistical and computer simulation methods to precisely control and predict membrane fouling;conducting further research on reducing the production of microbial EPS by changing the aggregation of sludge particles to better alleviate membrane fouling.